Each year, billions of animals migrate in search of better conditions. These journeys shape ecosystems, drive evolution, and challenge individual survival. 



Migration, however, is not a simple instinctual response. It demands a blend of physical traits and behavioral choices. In <a href="https://www.earth.com/news/worlds-oldest-fish-coelacanth-presumed-extinct-for-60-million-years-before-rediscovery/" target="_blank" rel="noreferrer noopener">fish</a>, even a subtle anatomical difference - like eye size - can influence who migrates and who stays behind.



Recent research from <a href="https://www.lunduniversity.lu.se" target="_blank" rel="noreferrer noopener">Lund University</a> reveals that the European roach (Rutilus rutilus), a common freshwater fish, shows a surprising link between eye structure and migration behavior.



Specifically, roach that migrate between lakes and streams tend to have larger pupils than those who remain year-round in a single habitat. This physical feature helps them see better in murky water and boosts their ability to find food, a vital edge in the energy-intensive act of migration.



<h2 class="wp-block-heading" id="h-what-makes-a-fish-migrate">What makes a fish migrate</h2>



Roach are partial <a href="https://www.earth.com/news/native-fish-species-are-facing-double-trouble/" target="_blank" rel="noreferrer noopener">migrants</a>. That means only some individuals in a population leave the lake each winter to enter connected streams. 



The rest stay put, braving seasonal changes in place. This difference in behavior offers researchers a unique lens through which to understand how physical traits affect life strategies.



The research team, led by biologist Kaj Hulthén, tracked more than 2,000 roach across two Danish lakes - Loldrup Sø and Søgård Sø - over several years. 



They photographed the <a href="https://www.earth.com/news/climate-change-is-pushing-freshwater-fish-toward-the-poles/" target="_blank" rel="noreferrer noopener">fish</a>, implanted each one with a tiny transponder, and monitored <a href="https://www.earth.com/news/small-fish-species-are-the-big-catch-of-the-future/" target="_blank" rel="noreferrer noopener">movements</a> using underwater antennas placed at stream inlets and outlets.



“We started by taking photos of the fishes’ eyes and then followed the migration patterns of 2,000 individual roaches over several years and in two different lakes by using implanted electronic transponders,” said Hulthén, who is a biology researcher at Lund University.



“It was shown that roach that migrated had larger pupils relative to individuals that chose to stay in the lake throughout the year.” 



<h2 class="wp-block-heading" id="h-eye-size-matters-for-fish-that-migrate">Eye size matters for fish that migrate</h2>



Larger pupils allow more light into the eye, improving vision in low-light conditions. For roach, this visual boost helps detect tiny prey like zooplankton. Using simulations, the researchers showed that roach with larger pupils could see farther - especially in dim twilight conditions, when many <a href="https://www.earth.com/news/bleaching-effect-coral-loss-threatens-fisheries-and-livelihoods/" target="_blank" rel="noreferrer noopener">fish</a> feed.



Even a 1-4% increase in pupil diameter led to as much as a 5% increase in the volume of water a <a href="https://www.earth.com/news/fish-diversity-has-changed-dramatically-on-the-great-barrier-reef/" target="_blank" rel="noreferrer noopener">fish</a> could visually scan.



That matters because in aquatic environments, visual range often dictates feeding success. These small gains are enough to help migratory roach gather the energy reserves they need before entering food-poor winter streams.



In twilight, detection range for 1 mm prey reached up to 20 cm - enough for practical foraging. The advantage fades under starlight but remains relevant during dusk and dawn, which are key feeding times.



<h2 class="wp-block-heading" id="h-feeding-now-to-survive-later">Feeding now to survive later</h2>



Migrating roach face a trade-off. Streams have fewer predators but offer less food. To survive the winter, migrants must build up fat stores beforehand. Larger pupils may be a tool to gather more food before departure and to stay active longer each day by foraging in low light.



This connection between eyesight and feeding has deep evolutionary roots. Eye size reflects both opportunity and cost. Bigger eyes offer better vision, but they require more energy to build and maintain. For a migrating roach, the benefits seem to outweigh the cost.



“The fact that migrating individuals have an improved ability to detect visual objects such as zooplankton indicates strong selection for effective food searches. This is crucial to cover the energy needs that migration requires," said Hulthén.



"These results correspond well with previous research, which showed that migrating roach with insufficient energy reserves run a higher risk of dying in the streams."



<h2 class="wp-block-heading" id="h-fish-with-big-eyes-are-likely-to-migrate">Fish with big eyes are likely to migrate</h2>



In both study lakes, researchers found a clear pattern: roach with larger relative pupil sizes were more likely to migrate. 



The correlation was strongest in Søgård Sø, where murkier water creates a dimmer visual environment. This suggests that visual demands may vary by location, shaping individual behaviour accordingly.



On average, migrant roach in Søgård Sø had pupils 4.2% larger than residents. In Loldrup Sø, the difference was smaller at 1.1%. While modest, these changes are functionally significant. Larger pupils helped fish see better, especially in the dim light that dominates northern winters.



Roach are planktivores. They feed on small, fast-moving prey that require sharp eyesight to detect. Under experimental conditions, fish given more food before winter were more likely to migrate, did so earlier, and stayed in streams longer. Those with less food died more often. 



This supports the idea that strong visual skills, like those enabled by larger pupils, help fish meet their energy needs.



<h2 class="wp-block-heading" id="h-a-migratory-syndrome-takes-shape">A migratory syndrome takes shape</h2>



The study’s findings contribute to a growing view that migration is not just a behavioral choice. It’s a full-body strategy involving vision, body shape, energy storage, and risk-taking.



Together, these traits form a “migratory syndrome” - a suite of characteristics that help fish survive the challenges of moving between habitats.



The eye, often taken for granted in ecological studies, now appears central to this survival kit. By enhancing foraging efficiency, it helps determine who has the resources to leave and who stays behind.



“Roach play an important role in the ecosystem. By understanding why some individuals migrate and other don’t, we can gain a deeper insight into how fish populations respond to environmental changes, which in turn could affect both fish stocks and the lake dynamics as a whole,” said Hulthén.



<h2 class="wp-block-heading" id="h-fish-eyes-can-change-shape">Fish eyes can change shape</h2>



Whether these differences in eye morphology are genetic or a response to the environment remains unknown. 



However, past studies show that fish eyes can change shape depending on food availability and predator pressure. That means both nature and nurture could play roles in shaping eye size and which fish migrate.



Interestingly, the benefits of bigger eyes seem to matter most in moderate turbidity. In very clear water, all fish see well. In extremely dark or muddy water, vision may become useless. This window of usefulness hints at why migration-related eye differences show up more clearly in some lakes than others.



<h2 class="wp-block-heading" id="h-eye-size-and-fish-migration">Eye size and fish migration</h2>



Roach migration has ecological ripples beyond the fish themselves. Migrants affect predators, prey, and nutrient cycles. 



Understanding how physical traits like pupil size influence migration choices can help scientists predict how fish populations may respond to environmental change.



In this study, a tiny difference in pupil size revealed a key factor in migratory success. It highlights the tight link between form, function, and behavior.



Eyes, often symbols of awareness and insight, prove once again to be more than just windows to the world—they are tools of survival, helping fish decide whether to stay or go.



The study is published in the <a href="https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2656.70015" target="_blank" rel="noreferrer noopener">Journal of Animal Ecology</a>.



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Bigger pupils help migrating fish survive

Each year, billions of animals migrate in search of better conditions. These journeys shape ecosystems, drive evolution, and challenge individual survival. Migration, however, is not a simple instinctual response. It demands a blend of physical traits and behavioral choices. In fish, even a subtle anatomical difference - like eye size - can influence who migrates and who stays behind. Recent research from Lund University reveals that the European roach (Rutilus rutilus), a common freshwater fish, shows a surprising link between eye structure and migration behavior. Specifically, roach...

Conservationists brand tortoise shells to save species from the pet trade. The Ploughshare tortoise is known throughout the world for its memorizing, geometric shell. This shell makes the species stand out, especially in the illegal pet trade, which is causing Ploughshare tortoise populations to plummet.

The Ploughshare tortoise is currently listed as <a href="https://www.iucnredlist.org/species/9016/12950950">Critically Endangered</a> on the IUCN Red List as a result of smuggling for the pet trade and human-caused fires. Today, there are only around 400 individuals left living solely in Madagascar. The species holds the undesired title of the world’s rarest tortoise.

Demand for the Ploughshare tortoise has risen in recent decades among hobbyists and collectors who are willing to shell out large amounts of money for the tortoises. Conservationists brand tortoise shells to save species from the pet trade

This demand has fueled poaching in the wild as poachers often target species that will yield a high price in the wildlife market. Incentivizing the smuggling of Ploughshare tortoises more is the ease of taking them from the wild. Ploughshare tortoises have a highly limited distribution, allowing poachers to zero in on where they could find the species. Chasing and catching a tortoise is not a difficult task and Ploughshare tortoises have been<a href="https://www.biotaxa.org/hn/article/viewFile/11659/16038"> known</a> to get stuck between trees.

A<a href="https://www.researchgate.net/profile/Serene_Chng2/publication/317664475_Rising_internet-based_trade_in_the_Critically_Endangered_ploughshare_tortoise_Astrochelys_yniphora_in_Indonesia_highlights_need_for_improved_enforcement_of_CITES/links/59f92bf"> study</a> which examined the online market for Ploughshare tortoises found 88 advertisements selling 126 Ploughshare tortoises in a five-year period. The tortoises were highly valuable, selling for up to $47,000 USD each. Individuals have also been<a href="https://www.researchgate.net/profile/Vincent_Nijman/publication/266388361_Analysis_of_a_decade_of_trade_of_tortoises_and_freshwater_turtles_in_Bangkok_Thailand/links/542faf510cf277d58e91fd86/Analysis-of-a-decade-of-trade-of-tortoises-and-freshwate"> found</a> for sale at marketplaces.                               

Times are desperate for the Ploughshare tortoise. Despite protections by Madagascar law and international treaty, the illegal smuggling and trade persists. In 2016, a group of<a href="https://cites.org/sites/default/files/eng/cop/17/InfDocs/E-CoP17-Inf-36.pdf"> wildlife conservation groups</a> warned that the species could become extinct in the wild in the next two to three years.

In an attempt to curtail the trade, conservation groups have turned to an unlikely solution. The<a href="https://www.turtleconservancy.org/"> Turtle Conservancy</a>, a non-profit aimed at protecting turtles and tortoises, currently runs a program where turtles in the wild are safely marked with serial numbers on their shells. This approach hopes to curtail the demand for Ploughshare tortoises in the pet trade by making the individuals less attractive.

While it certainly is unfortunate to deface what makes the tortoise so iconic, the alternative is the likely extinction of the species. The Ploughshare tortoise faces a similar fate as other species whose beauty and unique attributes make them victim to overexploitation.

<a href="http://www.earth.com/news/northern-white-rhinos-genetics/">Rhinos</a>, who are targeted by poachers for their horns, have been the recipients of a few creative ideas to curtail demand for their parts. Some conservationists have suggested humanely shaving off rhinos’ horns and poisoning the horn itself. These ideas have been met with<a href="https://www.ifaw.org/united-states/news/why-some-creative-poaching-solutions-fail"> hesitancy</a> by some who question the efficacy of the ideas.

Although the shell marking program was controversial when it was first suggested, a similar program was conducted on Burmese star tortoises when they were reintroduced into the wild. The shell markings even helped prosecute two smugglers in Thailand, Turtle Conservancy<a href="https://www.turtleconservancy.org/news/2016/2/wild-ploughshare-tortoises-in-more-danger-than-ever"> notes</a>.

Despite ethical concerns about defacing the tortoises, the logic makes sense. Buyers are unlikely to spend $47,000 on a tortoise whose shell is damaged, especially if the serial number puts the buyer at an increased risk of detection.

Marking the shells of the Ploughshare tortoise is just one of the initiatives taking place to protect the species. The species’ habitat at Baly Bay was been established as a national park, tortoises have been<a href="http://www.chelonian.org/wp-content/uploads/file/CRM%206/26-Kiester&amp;al.pdf"> equipped with radio tags to track their movements and individuals have been bred in captivity</a>. The Ploughshare tortoise also needs increased enforcement around its habitat and internationally.

Without intervention, the only Ploughshare tortoises in the world may be living in the homes of the buyers who fueled their demise.

--

By <a href="mailto:brianna.grant134@gmail.com">Brianna Lynne</a>, <a href="http://earth.com">Earth.com</a> Contributing Writer

Image Credit: reptiles4all/Shutterstock

Conservationists brand tortoise shells to save species from the pet trade

Conservationists brand tortoise shells to save species from the pet...

Mass coral bleaching events can be devastating to coastal ocean ecosystems and research has shown that these events have become increasingly <a href="https://www.earth.com/news/mass-coral-bleaching-common/">frequent and widespread in recent years</a>. 

Climate change is a major driving factor in mass coral bleaching, and coral reef health is important when predicting how a reef will adapt to rising sea levels and temperatures.

Corals need herbivorous fish to graze on algae on the reef, and previously it was assumed that as long as fish populations remained high, coral reefs were healthy.

Now, a new study has found that diversity plays an equally important role as population numbers and biomass in keeping corals healthy and reef systems thriving.  

Researchers from the at <a href="https://www.bigelow.org/">Bigelow Laboratory for Ocean Sciences</a> recorded underwater footage of fish grazing along reefs in the Dominican Republic to assess how fish diversity impacted reef health.

The study was published in the journal Science Advances.

“Scientists have long known that reefs are healthier when a large number, or a ‘high biomass,’ of plant-eating fish graze their surfaces," said Doug Rasher, the senior author of the study. “However, this study revealed that having a diverse portfolio of those fish species on the reef is equally important to keeping reefs well grazed and hospitable to baby corals.”

When fish graze in coral reefs, they also double as the coral cleaning crew, scraping off seaweed and algae from the corals with their bodies.

Without fish to graze on them, seaweed and algae can overtake the reef and, in the Caribbean, this has become an increasingly common problem.

[caption id="attachment_1869250" align="aligncenter" width="650"]<a href="https://www.earth.com/wp-content/uploads/2019/03/parrotfish1.jpg"><img class="wp-image-1869250" src="https://www.earth.com/wp-content/uploads/2019/03/parrotfish1.jpg" alt="" width="650" height="430" /></a> A large stoplight parrotfish scrapes algae from the reef surface. Image Credit: José Alejandro Alvarez[/caption]

Each fish has their own preference when it comes the kind of algae they prefer, so it would make sense that a reef that houses a diverse number of fish species has a decreased risk of being overcome by seaweed.

The researchers wanted to see if diversity impacted reef health across a wide range of coral reefs or if it was a localized phenomenon that only benefitted certain reefs.

The team used underwater cameras to record fish activity at ten reefs spread across 1,000 kilometers of coastline in the Dominican Republic.

“Looking at reefs in isolation is like studying individual pieces of the puzzle,” said Rasher. “It is only by studying multiple reefs across an entire region that we could see the much larger role that biodiversity plays in supporting the process of grazing.”

Along with recording the fish, the researchers also measured algae abundance both before and after the fish fed on the corals and the number of baby corals.

Next, the researchers analyzed the video footage and took note of the diversity and sizes of the grazing fish.

A model was designed to process the data and compare the effectiveness of fish diversity to fish biomass on grazing.  

The model confirmed the importance of fish diversity on reef health, and the researchers say the study has important implications for managing tropical fisheries as conservation and management has typically focused on population size and not the number of species present.

“Our research helps bring coral reefs in line with what we know from many other ecosystems - from seagrass beds to forests and grasslands,” said Jon Lefcheck, the lead author of the study. “It appears more and more likely that biodiversity is the lynchpin that holds nature together.”

--

By <a href="mailto:kayvandette@gmail.com">Kay Vandette</a>, <a href="https://www.earth.com/">Earth.com</a> Staff Writer

Paid for by <a href="http://earth.com">Earth.com</a>

Main Image Credit: José Alejandro Alvarez

Both diversity and abundance are key to coral reef health

Mass coral bleaching events can be devastating to coastal ocean...

Dinosaurs were flourishing just before they were killed off. Most scientists agree that <a href="http://www.earth.com/news/asteroid-dinosaurs-global-tsunami/">dinosaurs</a> were killed off at the end of the Late Cretaceous period by a large asteroid impact, which was likely combined with intense volcanic activity. On the other hand, many experts disagree on the overall state of the dinosaurs just before they were wiped out. 

A new study led by <a href="https://www.imperial.ac.uk/">Imperial College London</a> has found that dinosaurs had survived millions of years of long-term climate changes and were flourishing at the time of the devastating asteroid strike. This discovery contradicts the findings of previous studies which concluded that the dinosaurs were in a state of decline when they were killed. 

Study lead author Alessandro Chiarenza is a PhD student in the Department of Earth Science and Engineering at Imperial.

“Dinosaurs were likely not doomed to extinction until the end of the Cretaceous, when the asteroid hit, declaring the end of their reign and leaving the planet to animals like mammals, lizards and a minor group of surviving dinosaurs: birds,” said Chiarenza.

“The results of our study suggest that dinosaurs as a whole were adaptable animals, capable of coping with the environmental changes and climatic fluctuations that happened during the last few million years of the Late Cretaceous. Climate change over prolonged time scales did not cause a long-term decline of dinosaurs through the last stages of this period.”

North America, where many Late Cretaceous dinosaurs are preserved, was split in half by a body of water during this time period. A steady supply of sediment from the newly forming Rocky Mountains created the perfect conditions for fossilization in the west, but the conditions in the eastern half of the continent were not nearly as suitable for fossilization. For this reason, far more dinosaur fossils are found in the western half of North America and this fossil record has been used for most research.

“Most of what we know about Late Cretaceous North American dinosaurs comes from an area smaller than one-third of the present-day continent, and yet we know that dinosaurs roamed all across North America, from Alaska to New Jersey and down to Mexico,” said study co-author Dr. Philip Mannion from the <a href="https://www.ucl.ac.uk/">University College London</a>.

The research team used a technique known as “ecological niche modeling,” which accounts for the environmental conditions that a particular species needs to survive.  This made it possible for the experts to gain new insight into where dinosaur species would have survived, rather than simply basing their existence on where fossils had been recovered. 


The study revealed that habitats which could support a range of dinosaurs were more widespread at the end of the Cretaceous than what was thought. The previously unknown territories were located in regions that were less likely to preserve fossils. This means that the number, as well as the diversity, of dinosaurs that were alive in the Late Cretaceous has been largely underestimated. 

The research is published in the journal <a href="https://www.nature.com/ncomms/">Nature Communications</a>.

--

By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Image Credit: Davide Bonadonna

Dinosaurs were flourishing just before they were killed off

Dinosaurs were flourishing just before they were killed off. Most...

By now, everyone’s heard of the threats facing <a href="http://www.earth.com/news/fungicide-honey-bees-death/">honey bees</a> these days in the United States, from pesticides to the steady invasive creep of urbanization.  But few people think about the native bee species and how these interact with the non-native European honey bee or the ‘Africanized’ hybrid that so many people fear.  Native bees are victims to human activity just as the loyal pollinating honey bees we so love.

According to the <a href="https://www.usda.gov/oce/forum/past_speeches/2015_Speeches/SDroege.pdf">USDA</a>, there are 20,000 named species of bees worldwide.  There are estimated to be another 20,000 species of bees left to describe.  In the US, there are approximately 4,000 species of described bees and an estimated 400 species left to describe.  The highest diversity of bees here is in the Southwest. With overlapping populations, there are 100+ species at any given location in the US.  Only about 1% of the bees in the US are non-native. Of the native bees in the US, most are incapable of stinging. Mexico also has a large amount of bee diversity.

According to <a href="https://ourworld.unu.edu/en/protecting-native-bee-populations-in-mexico">UN University</a>, there are 2,000 species of bees native to Mexico.  Beekeeping in Mexico is a big business, with 41,000 honey producers raising 2 million hives with a profit in exports of about US $56 million per year.  Honey production includes both European Honey bees (Apis mellifera) and native species.  The honey produced by each species of bee differs in its flavor as well as the amount produced.  Colony sizes in European and native bees also differ greatly. European honeybee colonies range in size from 30,000 to 50,000, while native colonies are usually much smaller from 1,000 to 5,000 worker bees.  Interestingly, native apiculture still remains in Mexico.

Native American communities in Mexico sometimes use pre-Columbian techniques in raising bees, such as using clay pots instead of more modern containers.  Sometimes native bees are used as well, contributing to the natural biodiversity of bees in Mexico. There is also one big advantage to raising native bees, unlike their European relatives, native bees don’t sting.  Being stingless, native bees are much easier to handle than the European Honeybee. There is also an ecological advantage – native bee species pollinate higher up in the colony of native tropical forests than do the introduced European bees.  Despite the benefit of not being attacked by a bee and the benefit to tropical forests, native bees are usually less profitable because they produce smaller volumes of honey per colony. 

When Native Americans encountered European Honey bees in North America, they often called them the ‘white man’s fly’.  Seeing large numbers of honey bees meant European settlers were nearby, while Native Americans had already been collecting honey from native bee colonies they found in the wild.  In Mexico, the Maya had long been practicing bee husbandry when Europeans first arrived in their land.

In 2005, the <a href="https://stri.si.edu/">Smithsonian Tropical Research Institute</a> reported that the main native species propagated by the Maya was Melipona beecheii, one of about 500 species of stingless bees found in the tropics.  16 species of stingless bees are native to the Yucatan region. The bee’s name in Yucatec Mayan is ‘Xunan-Kab’ which translates into, ‘royal lady bee’.  Traditionally colonies of these stingless bees were reared by a Mayan priest and honey was harvested only twice a year, to avoid damage from over harvesting.  

Researchers from the Smithsonian Institute of Tropical Research then decried the decline of native bee husbandry among the Mayan people of Mexico.  The decline is connected to a loss of cultural knowledge – the majority of Mayan bee keepers in Mexico are old men who aren’t passing there knowledge on.  Decline of bees as with the decline of all native species is also connected to a decline in habitat. Melipona beecheii depends on tropical forests for their survival and production of honey.  Given the threats to native honey bees, despite the 3,000 year history of beekeeping in Mexico, many Mayans are turning to European bees for beekeeping.  

By 2005, there had already been a 93% decline in native bee keeping.  1,000 native bee colonies were known in 1981 but only 90 remained in 2004.  At the time, biologist Rogel Villanueva Gutiérrez predicted that native bee production would be completely gone by 2008.  <a href="https://news.mongabay.com/2019/01/house-of-the-royal-lady-bee-maya-revive-native-bees-and-ancient-beekeeping/">Mongabay</a> reported in 2018 that these predictions didn’t turn out to be entirely accurate.  

Villanueva himself brought together 50 local people in the Mexican state of Quintana Roo and taught them native bee husbandry in an attempt to save the tradition, the bee itself and contribute to forest health.  From these modest beginnings, native bee keeping has grown and the state government has taken on financing some beekeepers. One family in the agricultural community of La Pantera has 98 bee colonies, more than all the native bee colonies being kept in Quintana Roo in 2004.  

An agroecological School in Yucatán state, founded in 1992 by a Catholic priest is also part of the renewal in native bee keeping.  The school has trained 300 Mayan students in native bee keeping and even more in agroecology. This training is spreading the renewal in native bee keeping to  Yucatán as well as Quintana Roo. Some are concerned with possible bad actors in native bee keeping.

Wild bee hives are sometimes raided to create a new colony of native bees for a quick profit, hurting wild populations.  Older people also sometimes sell their bee colonies for a profit without passing down their deep, traditional knowledge to younger generations.  There are also concerns about those who start in the business without a good grounding in apiculture training and end up killing or hurting colonies by their ineptitude.  Still, a revival in traditional knowledge and connection to native wildlife is a good thing. 

Beekeeping in the Yucatán peninsula of Mexico shows a way that agriculture and wild ecology can coexist, a way humans have discovered of being comfortable as part of a greater environmental whole.  Yucatán state has a history of colonial violence and oppression of Mayans, greater than in Quintana Roo. Revival of native beekeeping can be seen as a small revival of a culture long persecuted by colonists.           

--

By <a href="mailto:zachfitzner@yahoo.com">Zach Fitzner</a>, <a href="http://earth.com">Earth.com</a> Contributing Writer

Mexican beekeepers help native bees come back from the brink

By now, everyone’s heard of the threats facing honey bees...

Can FIV positive and negative cats live together? Working at a free-roaming cat rescue had many perks but perhaps my favorite was watching the adoptable cats interact and play with each other. These <a href="http://www.earth.com/news/cats-friendly-cues-humans/">cats</a> were varied in their backgrounds, some were rescued outdoors while some were owner-surrendered, some were seniors while others were kittens, and some were diagnosed with feline immunodeficiency virus (FIV) while others were not.

FIV is a virus, similar to HIV, that impacts a cat’s immune system making them increasingly vulnerable to other illnesses. Years ago, FIV meant euthanasia for many cats brought to shelters and rescues. But as veterinarians and researchers learned more about the virus, opinions began to change about how to treat FIV positive cats.

Although the symptoms of FIV can be severe, FIV positive cats can live healthy lives for years after their diagnosis. The <a href="https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center">Cornell Feline Health Center</a> estimates that the median survival time for a cat diagnosed with FIV is<a href="https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-immunodeficiency-virus"> five years</a>. Additionally, a<a href="http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.1034.1044&amp;rep=rep1&amp;type=pdf"> study</a> published in the Journal of Feline Medicine and Surgery found that the median survival time of FIV positive cats was not significantly different than FIV negative cats. In light of this, adopters can now find FIV positive cats readily available for adoption.

Cat rescues vary on how to house FIV positive cats in their care. FIV positive cats may be isolated or they may cohabitate with the other cats, such as at the rescue I had worked for.

Shelters and rescues may be hesitant to implement cohabitation policies between FIV positive and negative cats because FIV can be transmitted from cat to cat (it can not be transmitted to other animals or humans). The<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3439265/"> primary mode of the transmission</a> of FIV is through bite wounds which can occur through fighting or mating. Less common, is the transmission of FIV from mother to kittens and from mating itself. Can FIV positive and negative cats live together?

Cats who are not sterilized are at an increased risk of fighting and mating with other cats, which is why<a href="http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.1034.1044&amp;rep=rep1&amp;type=pdf"> free-roaming, aggressive male cats</a> are the most frequently infected. Shelters and rescues regularly mandate that all cats in their care have to be sterilized, which greatly reduces the risk of transmission by controlling testosterone and desires to fight over territory and mates.

This does not mean there is no chance of transmission between FIV positive and negative cats. Sterilized cats may still fight each other but rarely do these interactions result in forceful biting and open wounds.

A 2014<a href="http://maddieslifesavingacademy.org/wp-content/uploads/2018/05/Litster-2014-TVJ-Tmission-FIV-cohabiting-cats-2-rescue-shelters.pdf"> study</a> published in The Veterinary Journal examined the transmission of FIV between 138 cohabitating cats and found no evidence of transmission despite years of close contact. The cats living together engaged in grooming and sporadic fighting and shared food bowls, litter boxes and bedding. This study is in line with three previous studies which also found no transmission of FIV between positive and negative cats.

However, a 2000<a href="https://www.ncbi.nlm.nih.gov/pubmed/10811262"> study</a> published in The Veterinary Record found that six FIV negative cats became infected while living with FIV positive cats over a ten-year period.

Allowing FIV positive and negative cats to live together is not universally accepted in the animal welfare field. Some professionals still advise against the practice. Those who are in favor of the practice emphasize that the risk of transmission is low and that animal owners can monitor their cat’s behavior to ensure aggressive fighting is not occurring.

--

By <a href="mailto:brianna.grant134@gmail.com">Brianna Lynne</a>, <a href="http://earth.com">Earth.com</a> Contributing Writer

Can FIV positive and negative cats live together?

Can FIV positive and negative cats live together? Working at...

A research team led by the <a href="https://www.zsl.org/">Zoological Society of London (ZSL)</a>, the <a href="https://www.amnh.org/">American Museum of Natural History</a>, and the <a href="http://www.nmnaturalhistory.org/">New Mexico Museum of Natural History</a>, have discovered three new species and subspecies in fossilized <a href="http://www.earth.com/news/crocodiles-hide-caves/">crocodile</a> digestive remains. The fossilized bones, originally found between 1930 and 1990 and predicted to belong to a species that existed about 300 years ago, were discovered in caves, peat deposits, and sinkholes in the Cayman Islands.

The team found two new large rodents — Capromys pilorides lewisi and Geocapromys caymanensis — and a small shrew-like animal, dubbed Nesophontes hemicingulus. These three animals only existed in the Cayman Islands and likely went extinct in the 1700s after European settlers brought cat, dogs, and rat species to the Islands. 

This new discovery was published March 4th in the <a href="http://digitallibrary.amnh.org/handle/2246/7">Bulletin of the American Museum of Natural History</a>.

[caption id="attachment_1869143" align="aligncenter" width="650"]<a href="https://www.earth.com/wp-content/uploads/2019/03/new-mammal-species.jpg"><img class="wp-image-1869143" src="https://www.earth.com/wp-content/uploads/2019/03/new-mammal-species.jpg" alt="" width="650" height="797" /></a> Cuban hutia Capromys pilorides, the closest living relative to the newly described mammals, Image Credit: Nancy Albury[/caption]

"Humans are almost certainly to blame for the extinction of these newly described mammals, and this represents just the tip of the iceberg for mammal extinctions in the Caribbean,” said co-author Professor Samuel Turvey, Senior Research Fellow at the <a href="https://www.zsl.org/science">ZSL Institute of Zoology</a>. “Nearly all the mammal species that used to live on these tropical islands, including all of the native Caribbean sloths and monkeys, have recently disappeared.”

"It's vitally important to understand the factors responsible for past extinctions of island species, as many threatened species today are found on islands,” he continued. “The handful of Caribbean mammals that still exist today are the last survivors of a unique vanished world and represent some of the world's top conservation priorities."

When Sir Francis Drake visited the Islands in 1586 and recorded seeing “little beasts like cats,” which he also called “coneys,” he was most likely describing the Capromys and the Geocapromys, the researchers believe. Similar species to those of the Capromys and the Geocapromys have survived to modern day on Cuba. It is thought that the Cayman Islands became populated with mammals by way of said mammals being transported via floating vegetation from Cuba.

"Although one would think that the greatest days of biological field discoveries are long over, that's very far from the case,” added co-author Professor Ross MacPhee, of the <a href="https://www.amnh.org/our-research/vertebrate-zoology/mammalogy">American Museum of Natural History Mammalogy Department</a>. “With only one possible sighting early in the course of European expansion into the New World, these small mammals from the Cayman Islands were complete unknowns until their fossils were discovered.”

With their closest relatives residing on Cuba, MacPhee ponders the question, “how and when did they manage a 250-km journey over open water?"

--

By <a href="mailto:oliviagharvey24@gmail.com">Olivia Harvey</a>, <a href="http://earth.com">Earth.com</a> Staff Writer

New mammal species found in an ancient crocodile’s digestive system

A research team led by the Zoological Society of London...

The recovery of eastern Australian <a href="https://www.earth.com/news/protecting-their-habitats-is-key-to-the-recovery-of-humpback-whales/">humpback whales</a> should be a conservation success story after the whales in that area were hunted to near extinction by the 1960s due to commercial whaling. 

But now, a new study has found that although the population of humpbacks in the Australian Southern Ocean has almost completely recovered, their numbers are increasing at such a rapid rate that soon there won’t be enough food to sustain the whales. 

Competition for food and mates could cause a disastrous plummet in numbers, according to researchers from the <a href="https://gatton.uq.edu.au/">University of Queensland Gatton</a> who conducted the study which was published in the journal Population Ecology.

The researchers reviewed structured surveys of the humpback whales that were first conducted in the 1980s. 

The surveys are helpful in that they show a complete picture of population recovery through the years. By 2015, the humpback whales recovered and there were a little over 24,500 whales in total.

This recovery in numbers was due to an increase in conservation efforts and the Endangered Species Act. 

With the population continuing to grow at such a rapid rate, the researchers say that overpopulation will lead to competition for resources and population declines between 2021 and 2026. 

“Whale numbers are still steaming ahead at a tremendous rate — the population is virtually doubling every seven years,” said Michael Noad, the leader of the study. “They're either going to go up to a fairly high number and level off, about 40,000 or 50,000, or they could peak and then crash.”

If overpopulation were to occur, the researchers say that Australia would see more whale beachings and more whale carcasses at sea.

Whale declines would also be bad for tourism in the area which depends heavily on whale watching. 

The researchers say that continued monitoring is essential, as well as careful consideration for the health and wellbeing of the humpbacks if the population does start to decline. 

--

By <a href="mailto:kayvandette@gmail.com">Kay Vandette</a>, <a href="https://www.earth.com/">Earth.com</a> Staff Writer

Overpopulation of humpback whales could lead to disastrous decline

The recovery of eastern Australian humpback whales should be a...

The oldest horse fossils we can find are from North America.  When Europeans arrived in the Americas, horses had already moved across the Bering land bridge and made a home in Europe and Asia. Europeans of course brought their horses with them.

Camels appear to have first evolved in North America as well.  The lineage of camels split, with some migrating south, through Central America and into the Andes where they evolved into llamas.  Other camels crossed the land bridge and ended up as two species that can still be found in Africa and Asia. These stories of movement and evolution are common.  

Many animals and plants have deep evolutionary roots far from where they are found today.  Some biological lineages, such as birds, have simply spread across the world, evolving different forms and strategies to accommodate different environments.  Given enough time, the movement of organisms is one across the entire planet that shifts with the slow movement of continents themselves. 

You can see related and similar plants and animals mirroring each other in Africa and South America.  There’s a reason that hornbills and toucans look similar even though they live so far apart today. Movements from one place to another continue today just at a pace that’s hard to appreciate from the point of view of a short human life span.  Obviously, even our own species has moved across the globe, colonizing almost every livable spit of land. It’s only relatively recently with strict political borders that migrations human and otherwise have been put under so much pressure to halt.  

I previously <a href="https://www.earth.com/news/us-mexico-border-wildlife/">reported</a> on the fluidity of movement across the US-Mexico border by animals and parks that align with each other on both the Mexico and the US side of the border.  <a href="http://earth.com">Earth.com</a> has reported many times on the consequences that Trump’s proposed border wall would have on wildlife.  In August 2017, <a href="https://www.earth.com/news/us-mexico-border-wall-threaten-100-endangered-species/">we reported</a> that 100 endangered species would be threatened by the building of a border wall between the US and Mexico.  The problem goes even deeper than that, though. Barriers can shape evolution. Rivers, mountains, canyons, even deserts all act as natural barriers and have created the formation of different species.  To survive and thrive, lineages of organisms must travel and spread their genes across broad areas.

<a href="https://video.nationalgeographic.com/video/magazine/focal-point/00000163-0889-d820-a1e3-7aedafd20000?source=relatedvideo">National Geographic</a> reports that birds have 247 families and 10,731 species, the largest diversity in vertebrates besides fish, of which there are more than 33,000 species of fish globally, according to <a href="https://www.fishbase.de/home.htm">Fishbase</a>.  Why birds and fish are so diverse and found globally isn’t completely understood.  It does seem like diversity and widespread distribution go hand in hand to a certain degree.  Fish and birds have one thing in common besides a backbone – the ability to move long distances, through the oceans and skies respectively.  It seems likely that the ability of these animals to transport themselves long distances is related in some ways to their diversity. 

Bats, like birds, can disperse over long distances and are the second most species rich mammal order.  Whales are also part of one of the six most species rich orders within mammalia. Of course, the picture is a bit complicated.  Rodents don’t seem to have any special ability to spread across the world and there are more species of rodents than bats. Other groups of mammals are so diverse because they’re isolated.  Tenrecs in Madagascar are diverse because they arrived on an island with few species and were able to adapt to many wide open niches until there were 29 species of tenrec, most of them on Madagascar.  Over the long term, barriers like mountains, canyons, or walls affect diversity, evolution and ecology.  The ability to move often constitutes survival.

When habitat conditions such as prey availability or climate are changed, many animals have no other choice but to move to habitat with better conditions.  Jaguars have slowly been seen moving north into the United States. It’s unclear why exactly, but it could be that conditions are slowly becoming less favorable to the big cats south of the border and moving north is a means of survival.   

To pretend like a barrier, especially one that cuts off most of North America from Central America, won’t affect the entirety of the mainland Americas is simply incorrect.  On the other side of the issue, it’s unlikely the border wall will last more than a metaphorical blink of an eye in geologic time, and it seems unlikely it will really have any lasting effect on evolution.  It isn’t impossible though. 

A <a href="https://www.ncbi.nlm.nih.gov/pubmed/12634804">study</a> from 2003 suggests that the Great Wall of China actually had an effect on evolution.  The study looked at gene flow between five plant species that live on each side of the wall.  The researchers found that there was a greater difference in diversity between populations divided by the wall than control populations divided by a simple mountain path.  Essentially, the wall is a barrier to gene flow. Gene flow is important to evolution. A small population without new genes can wither and die from inbreeding. Two large populations with slightly different genetic makeup can evolve into separate species if isolated from one another long enough.  Both of these outcomes are possible from the wall Trump is now trying to build under an emergency declaration.

Even if the wall is built but only lasts for a short time, it may have long lasting effects.  The <a href="https://www.bbc.com/news/world-europe-27129727">BBC</a> reported in 2014, 25 years after the iron curtain fell, the deer still avoid the border of Germany and the Czech Republic.  Most deer stick to their side of the border, despite the once electrified barrier fence being removed. Researchers tracked 300 deer with radio collars to conclude that mainly, the deer don’t cross the border.  Even an imaginary barrier such as this one could shape the evolution of an organism. If the deer don’t commingle, they might as well be separated by a wall or fence.

The truth is – we don’t fully understand the full consequences of a border wall between the US and Mexico – which should be enough to make us take a step back and think long and hard.               

--

By <a href="mailto:zachfitzner@yahoo.com">Zach Fitzner</a>, <a href="http://earth.com">Earth.com</a> Contributing Writer                   

Paid for by <a href="http://earth.com">Earth.com</a>

Human-made borders can have lasting effects on the natural world

The oldest horse fossils we can find are from North...

A new study has revealed that many dog food products made with raw meat contain high levels of bacteria that threaten the health of both animals and people. According to the researchers, the products are particularly dangerous for infants, elderly adults, and individuals with weak immune systems. 


Raw meat products are often considered to be a healthier, more natural alternative to commercial <a href="http://www.earth.com/news/dog-food-meat-pet/">dog food</a> products. Unlike commercial foods, however, raw meat products are not pasteurized to ensure the safety of their contents. 

The researchers tested samples of 60 packs of raw meat products, which were produced by 10 different manufacturers in Sweden, Norway, Finland, Germany, and England. The dog food products all contained at least one of the following: uncooked meat or edible bones/organs from cattle, chicken, lamb, turkeys, pigs, ducks, reindeer, or salmon. Some of the products also contained vegetables and minerals.


The samples were analyzed for bacteria that could potentially pose a health risk to animals and people. The testing revealed that all 60 samples contained a family of disease-causing bacteria known as Enterobacteriaceae, which is indicative of fecal contamination. 

The levels of Enterobacteriaceae varied widely among the different manufacturers, but over half of the samples contained levels that exceeded the limit set by the European Union (EU). C perfringens, another marker of fecal contamination and hygiene standards, was found in 18 samples.

E coli was found in about one-third of the samples, and Salmonella species were found in four out of 60 samples. While this does not sound like a lot, EU regulations do not permit Salmonella in any animal feed.

The research highlights the importance of careful storage, handling, and feeding of raw meat dog food products. The experts recommend that raw meat dog food should be kept frozen until use, thawed at 10 degrees Celsius, stored away from other food, and handled with separate kitchen equipment.

“Dogs in families with infants, elderly people or immunocompromised individuals should also not be fed (raw meat products), as these groups are more susceptible to infections,” wrote the study authors. 

British Veterinary Association (BVA) Junior Vice President Daniella Dos Santos said that the research offers “further compelling evidence” to support concerns about the health risks associated with a raw meat-based diet.

“Bacteria such as E coli and Salmonella can cause significant gastrointestinal disease in animals. Pets can also shed potentially harmful pathogens present in raw food into their environment, so there is a risk to owners both in handling the food and coming into contact with the animal. Pet owners who choose to feed a raw food diet should be aware of the potential health risks and take full precautions while storing and handling the food,” said Dos Santos. 

“BVA would also not recommend making a raw food diet at home without veterinary guidance due to the potential for nutritional deficiencies in homemade diets. We would advise any owner wanting to try a raw meat-based diet for their pet to first consult a veterinary surgeon.”

The study is published in the journal <a href="https://veterinaryrecord.bmj.com/">Vet Record</a>.

--

By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Harmful bacteria found in dog food containing raw meat

A new study has revealed that many dog food products...

A team of biologists set out to investigate how <a href="http://www.earth.com/news/blue-whales-memories-feeding-sites/">blue whales</a> respond when they are exposed to sonar. The researchers, led by Brandon Southall from the <a href="https://www.ucsc.edu/">UC Santa Cruz</a>, discovered that some blue whales stop feeding on deep patches of krill when they encounter sonar.

“The ocean is a big place and it can be easy to miss and lose even the biggest animals ever on the planet, but, because they are so large and have very tall blows, they are actually among the easiest marine mammals to track,” said Southall. 

He described how the scientists managed to tag the massive animals in a six meter inflatable boat. 

“The driver of the small boat is totally critical, we had one of the most experienced people in the world doing this: John Calambokidis from the Cascadia Research Collective.”

The suction tags recorded the whale’s depth, movement, and sounds in the water. The team generated sonar signals from a boat located about a kilometer away for 30 minutes or an hour. Meanwhile, six trained experts observed the reactions of the whales as the sonar grew louder and then after the noise ceased.

Over the course of five years, the researchers recorded the responses of whales to 42 sonar tests. The information logged by the tags was analyzed and then combined with observations at the surface, to look for patterns and changes in behavior. 

While the majority of the deep-diving whales stopped feeding when the sonar signals started, the whales near the surface did not respond even when the sonar was loud and nearby. In addition, some whales stopped feeding and headed away from the sonar emissions. Most of the whales resumed their activities soon after the sonar stopped. 

Southall was surprised by how different the whales' reactions were. 

“Some whales responded when the sound was barely audible, while others seemingly ignored it and kept feeding at quite loud levels,” said Southall, which he referred to as a “really big deal.” 

“The current management approaches rely very heavily on the amplitude level (volume) to predict response.” 

However, the activity that the whale is engaged in seems to have a bigger influence on how much the sonar disrupts its behavior.

Southall concluded, “Impacts could be minimized by reducing sonar disturbance during periods of blue whale foraging on deep patches of krill in the military's main training areas.”

The study is published in the <a href="http://jeb.biologists.org/">Journal of Experimental Biology</a>.

--

By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Image Credit: NOAA

Sonar signals disrupt feeding time for blue whales

A team of biologists set out to investigate how blue...

A team of ecologists at <a href="https://www.yale.edu/">Yale University</a> investigated how potential changes in land cover may impact the geographic distributions of about 19,400 species worldwide. They found that by 2070, an increase in land use for <a href="http://www.earth.com/news/freshwater-bodies-increasingly-polluted/">human activities</a> will shrink the natural habitats of 1,700 species, putting them at a greater risk of extinction. 

The changes in land cover projected in the research were based on four different trajectories that scientists have established as being likely. The scenarios represent reasonable expectations about upcoming developments in society, demographics, and economics on a global scale.

Study co-author Walter Jetz is a professor of Ecology and Evolutionary Biology and of Forestry and Environmental Studies at Yale.

“Our findings link these plausible futures with their implications for biodiversity,” said Professor Jetz. “Our analyses allow us to track how political and economic decisions - through their associated changes to the global land cover - are expected to cause habitat range declines in species worldwide.”

With just moderate changes in human land-use, the experts determined that about 1,700 species will likely lose between 30 and 50 percent of their current habitat ranges by 2070. The species, which will become much more vulnerable to extinction, include 886 species of amphibians, 436 types of birds, and 376 species of mammals.

“The integration of our analyses with the Map of Life can support anyone keen to assess how species may suffer under specific future land-use scenarios and help prevent or mitigate these effects,” said study co-author Ryan P. Powers.

The greatest habitat loss and extinction risk will be suffered by species in Central and East Africa, Mesoamerica, South America, and Southeast Asia.

“Losses in species populations can irreversibly hamper the functioning of ecosystems and human quality of life,” said Professor Jetz. “While biodiversity erosion in far-away parts of the planet may not seem to affect us directly, its consequences for human livelihood can reverberate globally. It is also often the far-away demand that drives these losses - think tropical hardwoods, palm oil, or soybeans - thus making us all co-responsible.”


The study is published in the journal <a href="http://www.nature.com/natureclimatechange">Nature Climate Change</a>.

--

By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Paid for by <a href="http://earth.com">Earth.com</a>

Human activity will shrink natural habitats of 1,700 species by 2070

A team of ecologists at Yale University investigated how potential...

Shortfin mako sharks can zip through the water at estimated speeds of 70 to 80 miles per hour, which is why they have been referred to as the “cheetahs of the ocean.” A research team led by aeronautical engineer Amy Lang of the <a href="https://www.ua.edu/">University of Alabama</a> set out to investigate how mako sharks achieve such speeds by testing skin samples.

The experts were particularly interested in the effect of microscopic scales found in specific locations on the shark's body, such as on the flank and the fins. The scales can flex at angles in excess of 40 degrees from the body in the opposite direction of the flow of water, which causes resistance. 

“It impedes the flow from reversing near the skin, which would otherwise lead to what we call flow separation,” said Lang. “This is the drag you experience if you stick your hand out your car window vertical to the airflow.”

There is high pressure pushing back on the front of your hand, while low pressure is pushing forward on the back of your hand. Together, these pressure forces produce a net force of drag. Lang explained that the same is true any time a flow separates, even on a smooth body like a <a href="http://www.earth.com/news/risk-shark-attacks-remains-low/">shark</a> - or a golf ball.

“The dimples on a golf ball are an example of separation control that reduces pressure drag by maintaining attached flow around the ball and reducing the size of the wake. You can hit a golf ball with dimples 30 percent farther than if the same ball were smooth,” said Lang.

“We set up an experiment in the tunnel with a measured amount of flow separation induced on a smooth surface. Then we replaced the smooth surface with shark skin and re-quantified the flow separation. In all cases with the flank skin, we saw the size of the separated flow region reduced significantly by the presence of the skin.”

[caption id="attachment_1869002" align="aligncenter" width="650"]<a href="https://www.earth.com/wp-content/uploads/2019/03/scales.jpg"><img class="wp-image-1869002" src="https://www.earth.com/wp-content/uploads/2019/03/scales.jpg" alt="" width="650" height="488" /></a> Shortfin mako shark scales, Image Credit: Phil Motta at the University of South Florida[/caption]

The research team discovered that flow separation was being controlled by a “passive bristling” capability that is made possible by the surface geometry on the shark's scales.

Lang added, “The potential for a man-made surface to utilize this entirely passive mechanism even in air is very exciting.”

The research will be presented this week at the 2019 <a href="https://www.aps.org/">American Physical Society</a> March Meeting in Boston.

--

By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

How mako sharks can swim as fast as 80 miles per hour

Shortfin mako sharks can zip through the water at estimated...

Scientists are transforming chocolate into a functional food by infusing it with probiotics and prebiotics, aiming to create a treat that satisfies cravings while supporting gut health. 



The challenge lies in maintaining chocolate's beloved texture and flavor while adding health benefits.



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https://youtu.be/Ug657J67iEo?si=w96YjGMsg939LD_3
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Probiotics - beneficial microbes that balance gut bacteria and aid digestion - are typically fragile and can be destroyed by stomach acid or processing. 



Prebiotics act as food for these microbes, helping them thrive. Together, they form "synbiotics," a powerful health combination.



Researchers Smriti Gaur and Shubhi Singh from India's Jaypee Institute of Information Technology took an innovative approach, using natural prebiotics like corn and honey instead of complex processing methods. 



They created five chocolate varieties: a control and four synbiotic versions containing different combinations of prebiotics, probiotics (Lactobacillus strains), and flavor enhancers (cinnamon or orange).



Laboratory simulations of human digestion showed the probiotics remained viable for over five hours, suggesting they could survive long enough to benefit gut health.



Taste tests were positive, with researchers particularly enjoying the orange-flavored variety, describing it as having "vibrant citrus notes" complementing the "rich cocoa" with a "luxurious" texture.



This research represents just the beginning. With further refinement of strains, textures, and flavors, chocolate could evolve beyond mere indulgence to become a functional food that nourishes while it delights.



The study is published in the journal <a href="https://pubs.acs.org/doi/10.1021/acsfoodscitech.4c00741" target="_blank" rel="noreferrer noopener">ACS Food Science &amp; Technology</a>.

Is chocolate the next nutritional powerhouse?

Scientists are transforming chocolate into a functional food by infusing...

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Nushagak Bay, a large estuary in southwest Alaska. Nushagak runs mainly north to south and exits in Bristol Bay, a large body of water in the Bering Sea.



"The bay is primarily fed by the Nushagak River, which begins in the Alaska Range and flows southwest approximately 450 km. The bay is also fed by several additional rivers including the Wood, Igushik, Snake and Weary rivers," says ESA.



"The dark colors of the Nushagak River are most likely due to tannins or lignins (chemical substances found in plants). Tannins and lignins from roots, leaves, seeds, bark and soil can leach into the water and give it a brown or even black colour. The sediments then flow southwards where it is mixed with the bluer waters of the bay."



Video/ Image Credit: ESA



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Nushagak Bay in southwest Alaska

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Today's Video of the Day from the <a href="https://www.acs.org/">American Chemical Society</a> (ACS) reveals that proteins on flu viruses are actually flexible, tilting and waving in a “breath-like” motion. According to the experts, these proteins could be used to better defend against the flu.



"The main antigenic targets of influenza virus are two surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA). Whereas the structural and dynamical properties of both glycoproteins have been studied previously, the understanding of their plasticity in the whole-virion context is fragmented," wrote the researchers.



To investigate, the team conducted detailed simulations of the influenza A H1N1 virion, or the swine flu. The experts concluded that the visualizations show many new vulnerable states of flu viruses, which could improve future vaccines and antiviral drugs.



Video/ Image Credit: American Chemical Society&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Flu viruses are more flexible than expected

[sendtonews key="G9bUoxcjr4-2511624-12187" type="single"] Today's Video of the Day from the...

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Lake Trasimeno, which is located west of Perugia in central Italy. It is the fourth largest lake in the country. While Trasimeno’s water level varies, it has a maximum depth of approximately six meters.&nbsp;



"In this Copernicus Sentinel-2 image, captured on 6 August 2022, the lake’s emerald green colour is likely due to the presence of phytoplankton. Streaks in the water, particularly visible in the west, indicate the presence of soil and sediments which have been stirred up by winds. Dark colored waters in the southern part of the lake indicate a presence of submerged and floating macrophytes (aquatic plants) as well as algae," says ESA.



"Surrounded by hills on three sides, Trasimeno is subject to heavy storms created by winds, especially from the north and west. There are three islets in the lake: Maggiore, Minore and Polvese (the largest). The lake’s shores are sparsely inhabited with only two popular villages: Castiglione del Lago and Passignano sul Trasimeno."



"Italy is experiencing its worst drought in 70 years which has affected drinking water supplies, hydroelectric power and agricultural production. High temperatures, hot winds and lack of rainfall are the main causes of drought in the Umbrian region which saw Lake Trasimeno’s drop 1.3 m, reaching the limit of the hydrometric zero in July 2022."



Video/Image Credit: ESA&nbsp;



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Lake Trasimeno in Central Italy

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Today's Video of the Day from the <a href="https://www.acs.org/">American Chemical Society</a> describes a new self-powered nanosensor that can instantly detect mercury contamination with the tap of a finger.&nbsp;



The oxidized form of mercury can be harmful when it is ingested through contaminated water or food. This makes it necessary for experts to develop sensors that can quickly and accurately detect the presence of mercury.&nbsp;



Zong-Hong Lin and colleagues have now created a triboelectric nanosensor (TENS) that can detect mercury by simply by touching a sample. According to the researchers, their TENS could serve as the basis for similar devices to safely and remotely monitor other pollutants.



Video Credit: American Chemical Society&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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Detecting mercury contamination with the tap of a finger

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Today’s Video of the Day from the <a href="https://www.acs.org/">American Chemical Society</a> explores the ability of salt to transform the way that foods and beverages taste. Salt is known to cover up undesirable flavors, such as bitterness in coffee or beer, but how exactly does sodium chloride change the taste of other compounds?



One previous study showed that, not only does salt suppress bitterness, but also enhances sweetness and sourness. Another study revealed that bitterness reduction by salt seems to be happening at the tongue receptor level as well as in the brain.&nbsp;



While it is known that salt taste is mediated by the presence of sodium channels in the form of taste buds, experts believe that there is also an unknown receptor responsible for how we taste salt that has not yet been identified.&nbsp;



Video Credit: ACS Reactions



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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How does salt makes things taste better?

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Santiago, the capital city of Chile. The city is located in the center of the Santiago Metropolitan Region, which has a population of about eight million people.&nbsp;



'The weather of Santiago resembles the Mediterranean climate with dry and warm summers with temperatures reaching up to 35°C (from October to March) and cool and humid winters that can drop to 0°C (from April to September)."



"The city lies in the centre of the country’s central valley around 80 km from the Pacific Ocean to the west and borders Argentina to the east. A tiny part of Argentina is visible in the top-right corner of the image where the mountain crest of the Andes Mountains acts as a divider between the two countries," says ESA.



Video/ Image Credit: ESA



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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Santiago, Chile in South America

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Spiral,Galaxy,,Illustration,Of,Milky,Way

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Astronomers at <a href="https://www.jhu.edu/">Johns Hopkins University</a> have created an interactive map of the universe, including the actual position and real colors of 200,000 galaxies. The map allows the public to access data that was previously only available to scientists.



The map was developed using data collected by the Sloan Digital Sky Survey. For over two decades, a telescope in New Mexico was aimed at slightly different locations to capture the night sky.&nbsp;



"Growing up I was very inspired by astronomy pictures, stars, nebulae and galaxies, and now it's our time to create a new type of picture to inspire people," said map creator Brice Ménard, a professor at Johns Hopkins. "Astrophysicists around the world have been analyzing this data for years, leading to thousands of scientific papers and discoveries. But nobody took the time to create a map that is beautiful, scientifically accurate, and accessible to people who are not scientists. Our goal here is to show everybody what the universe really looks like."



"In this map, we are just a speck at the very bottom, just one pixel. And when I say we, I mean our galaxy, the Milky Way which has billions of stars and planets. We are used to seeing astronomical pictures showing one galaxy here, one galaxy there or perhaps a group of galaxies. But what this map shows is a very, very different scale."



"From this speck at the bottom, we are able to map out galaxies across the entire universe, and that says something about the power of science."



The <a href="https://mapoftheuniverse.net/">interactive map</a> is available online, where it can be downloaded for free.



Video Credit: Johns Hopkins&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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Interactive map of the universe includes 200,000 galaxies

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Lesotho: Africa's "Kingdom in the Sky" Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features northwest Lesotho in South Africa.



According to ESA, Lesotho is the only nation in the world that lies completely above 1,000 m in elevation. The country is famous for its tall mountains and narrow valleys, and is known as Africa's "Kingdom in the Sky."



Out of a population of around two million people, about 80 percent live in rural areas. More than 75 percent of these people are engaged in <a href="https://www.earth.com/news/climate-change-will-have-a-global-impact-on-agriculture/">agriculture</a>, including rainfed cereal production and animal grazing.&nbsp;



ESA reports that the country’s agricultural system faces a growing number of issues, with climate-related vulnerabilities such as drought, floods and extreme temperatures occurring more frequently. 



Diamonds are amongst the minerals found in the mountains. Indeed, Lesotho can truly be called the Kingdom in the Sky. Beautiful, culturally rich, safe, affordable, and easily accessible from Durban and Johannesburg, mountainous Lesotho is a vastly underrated travel destination. the Kingdom of Lesotho (Sotho: 'Muso oa Lesotho) is an enclaved country in southern Africa. It is just over 30,000 km2 (11,583 sq mi) in size and has a population of around 2 million.



Video Credit: ESA&nbsp;&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer 



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Lesotho: Africa's "Kingdom in the Sky"

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Today's Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Dublin, the capital and largest city of Ireland. Beyond its pub culture, Dublin is known as a modern culinary destination and a UNESCO City of Literature.



"Dublin is located near the midpoint of Ireland’s east coast in the province of Leinster. The city, which covers an area of around 115 square kilometers, is bordered by the Dublin Mountains, a low mountain range to the south, and is surrounded by flat farmland to the north and west," says ESA.



"The city straddles the River Liffey, which rises in the Wicklow Mountains and flows around 80 kilometers eastwards through the city of Dublin, in which it is canalised and bordered with quays. It then empties into Dublin Bay, an arm of the Irish Sea."



Dublin has an abundance of green spaces, including one of the largest enclosed public parks in any European capital city. Phoenix Park, which was originally formed as a royal hunting park in the 1660s, includes 707 hectares of green space.



Video Credit: ESA&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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The city of Dublin on Ireland's east coast

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Today's Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features the province of Zaragoza in northeast Spain. The image was captured by the Copernicus Sentinel-2 mission.



"Together with the provinces of Huesca and Teruel, Zaragoza formed the old kingdom of Aragon. Its capital, also called Zaragoza (not visible in this image) is home to around half of Aragon’s population," says ESA.



"The Ebro River can be seen winding its way through the province from west to east in this image. Between its source in the Cantabrian Mountains in the northwest and its delta on the Mediterranean coast, the Ebro River is fed by more than 200 tributaries as it flows 910 km across much of northern Spain."



Since rainfall is very scarce in this region, irrigation in the Ebro basin is critically important. In the valleys surrounding the Ebro River, many fields are used for growing crops such as corn, wheat, and barley.



Video/ Image Credit: ESA



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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The province of Zaragoza in northeast Spain

[sendtonews key="oL4FnPTGCV-2384527-12187" type="single"] Today's Video of the Day from the...

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Today’s Video of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> reveals the evolution of the Columbia Glacier in southeastern Alaska. Columbia is among the fastest shrinking glaciers in the world, and the video documents its rapid retreat over the years.&nbsp;



Columbia Glacier is a large, multi-branched calving glacier that flows out of the Chugach Mountains to the Prince William Sound.&nbsp;



According to USGS, Columbia had a long history of stability prior to 1980, with a length 41 miles, and small, short-lived advances or retreats.



In the years since 1980, however, satellite images have captured Columbia’s alarming retreat. By using false-color images, scientists can distinguish between snow and ice, open water, vegetation, and rocky debris on the glacier’s surface.



The series of false-color images featured in today's video were acquired over the span of 35 years. You can see that by 2021, the glacier’s main branch had retreated about 15 miles from its initial position.



The Columbia Glacier has also lost more than 50 percent of its volume, mostly due to calving. <a href="https://www.earth.com/video/nasa-reveals-3d-visual-of-an-atmospheric-river/">NASA</a> reports that while climate change likely started the retreat, mechanical processes kept the disintegration going.



The NASA images are provided by Jesse Allen, Robert Simmon, Joshua Stevens, and Lauren Dauphin using data from Landsat satellites, from the U.S. Geological Survey, and data from MODIS on NASA’s Terra satellite. The structure of Columbia’s moraine played a large role in the stability of the glacier before 1980. 



Like other tidewater glaciers, the Columbia built up a moraine over time, and the mixture of ice and rock functioned like a dam keeping out the sea. It was supported on one end by the shoreline and by the underwater terminal moraine at the other.



Video Credit: NASA Earth Observatory/&nbsp; NASA’s Scientific Visualization Studio



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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The rapid retreat of the Columbia Glacier

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features the Pyrenees Mountains, which form a natural boundary between France and Spain in southwest Europe.



The mountain range is 430 kilometers in length. It stretches from the Mediterranean Sea on the east to the Atlantic Ocean on the west.



At an elevation of 3404 meters, Pico de Aneto is the highest mountain peak in the Pyrenees, and the third-highest peak in Spain. Pico de Aneto is located in the Posets-Maladeta Natural Park, which spans more than 82,000 acres.&nbsp;



"Geological studies have revealed that the Pyrenees Mountains have been around for longer than the Alps, with their sediments first deposited in coastal basins during the Paleozoic and Mesozoic eras," reports ESA.



"The entire mountain range formed due to the upwelling of large sedimentary rocks by the collision of the Iberian and the Eurasian plate around 100 to 150 million years ago, followed by intense erosion from ice and water."



The western Pyrenees receive more precipitation due to moisture blowing in from the Atlantic Ocean. The mountain range contains many lakes, several small glaciers, and some of the highest waterfalls in Europe.



Video &amp; Image Credit: ESA



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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The Pyrenees Mountains in southwest Europe

[sendtonews key="6HyfrAJTBI-1831843-12187" type="single"] Today’s Video of the Day from the...

Earth,Like,Exoplanet,3d,Render

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Today's Video of the Day from <a href="https://www.nasa.gov/goddard">NASA Goddard</a> describes two exoplanets that are orbiting a star 218 light-years away. A team of researchers led by the University of Montreal has found evidence that these planets are "water worlds."



The experts used data from NASA’s Hubble and Spitzer Space Telescopes. They discovered that exoplanets Kepler-138 c and Kepler-138 could be composed largely of water.



"We previously thought that planets that were a bit larger than Earth were big balls of metal and rock, like scaled-up versions of Earth, and that's why we called them super-Earths," explained study co-author Björn Benneke.&nbsp;



"However, we have now shown that these two planets, Kepler-138 c and d, are quite different in nature and that a big fraction of their entire volume is likely composed of water. It is the best evidence yet for water worlds, a type of planet that was theorized by astronomers to exist for a long time."



Video Credit: NASA Goddard



Image Credit: NASA, ESA, and Leah Hustak (STScI)



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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Two distant planets may be "water worlds"

[sendtonews key="QIoVYJqRBi-2434608-12187" type="single"] Today's Video of the Day from NASA...

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Satellites reveal how Earth's systems are interconnected Today’s Video of the Day from <a href="https://www.nasa.gov/goddard">NASA Goddard</a> describes Earth’s interconnected systems, and how this network is affected by rising temperatures.&nbsp;



During 2020, average global temperatures matched the hottest year on record. The hurricane season was also record-breaking, with many of the storms intensifying at extraordinary speeds. Hot water in the ocean is fuel for hurricanes. The satellite data shows that it's all one interconnected system showing how Satellites reveal how Earth's systems are interconnected.



According to NASA, dust swept up from Northern Africa plays a major role in the formation of hurricanes, and is also a key source of fertilization in the Amazon rainforest. As a result of<a href="https://www.earth.com/news/seagrass-wasting-disease-is-fueled-by-climate-change/"> climate</a> change, dust plumes are expected to decline, which will have an effect on vegetation far away.&nbsp;



Images from Earth-observing satellites show how the world’s plant life is affected by natural disasters, fires, and deforestation. Satellites also reveal how widespread changes in vegetation impact waterways,&nbsp; the climate, air quality. Satellites communicate by using radio waves to send signals to the antennas on the Earth. "Earth From Space" is a groundbreaking two-hour special that reveals a spectacular new space-based vision of our planet. 



Video Credit: NASA Goddard&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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Satellites reveal how Earth's systems are interconnected

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Today’s Video of the Day from the <a href="https://welcome.miami.edu/">University of Miami</a> Rosenstiel School of Marine and Atmospheric Science explores how changes in water temperatures have affected tiger shark habitats and movements in the North Atlantic Ocean. The study reveals that rising temperatures have caused the sharks to shift toward the poles over the past 40 years.



“Tiger shark annual migrations have expanded poleward, paralleling rising water temperatures,” explained study lead author Neil Hammerschlag. “These results have consequences for tiger shark conservation, since shifts in their movements outside of marine protected areas may leave them more vulnerable to commercial fishing.”



The researchers analyzed nine years of tracking data from satellite-tagged tiger sharks, combined with four decades of conventional tag and recapture data provided by National Oceanic and Atmospheric Administration (NOAA) Cooperative Shark Tagging Program.



The experts found that during the last decade of record heat, for every one-degree Celsius increase in water temperatures, tiger sharks migrated further poleward by over 400 kilometers. They also migrated two weeks earlier than usual to waters off the northeastern coast of the United States.



“Given their role as apex predators, these changes to tiger shark movements may alter predator-prey interactions, leading to ecological imbalances, and more frequent encounters with humans,” concluded Professor Hammerschlag.



Video Credit: University of Miami Rosenstiel School of Marine and Atmospheric Science



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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Tiger sharks are shifting poleward as temperatures rise

Today’s Video of the Day from the University of Miami...

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> is focused on the melt ponds that emerge during the spring and summer on the Greenland Ice Sheet, which is the largest ice mass in the northern hemisphere.



"Melt ponds are vast pools of open water that form on both sea ice and ice sheets and are visible as turquoise-blue pools of water in this Copernicus Sentinel-2 image," says ESA.



"When snow and ice melts atop glaciers, water flows in channels and streams and collects in depressions on the surface. These melt ponds can speed up the melting of the surrounding ice since they greatly reduce the ice’s ability to reflect sunlight."



"This can create a positive feedback where an increasing number of melt ponds absorb more heat which causes ice cover to melt even faster."



According to ESA, Greenland has been hit with a late-season heatwave that began in early September. This caused the type of melt event that usually occurs in the middle of summer.



"In a recent paper published in Nature Climate Change, scientists found that major sea-level rise from the melting of the Greenland ice cap is now ‘inevitable’ even if the burning of fossil fuels were to halt overnight," says ESA. "Using satellite observations of Greenland ice loss and ice cap from 2000 to 2019, the team found the losses will lead to a minimum rise of 27 cm regardless of climate change."



Video Credit: ESA&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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Melt ponds on the Greenland Ice Sheet

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> describes a new map of Mars that is providing insight into the planet’s watery past. The map also reveals where future missions could safely land on Mars.&nbsp;



The map has been created over the last decade using observations of water-rich rocks and mineral deposits. The images were captured by ESA’s Mars Express and NASA’s Mars Reconnaissance Orbiter.



"A big surprise is the prevalence of these minerals, with the map revealing hundreds of thousands of water-affected locations in the oldest parts of the planet," says ESA. "The new data will help answer exciting questions about Mars’ climate history, whether water was globally persistent or confined to short, intense episodes, and whether the conditions were ever suitable for life."



"Specifically, the map shows the locations and abundances of aqueous minerals. These are from rocks that have been chemically altered by the action of water in the past, and have typically been transformed into clays and salts."



According to John Carter of the Institut d’Astrophysique Spatiale (IAS), our collective understanding of Mars has been oversimplified. He explained that planetary scientists have tended to think that only a few types of clay minerals on Mars were created during its wet period, then as the water gradually dried up, salts were produced across the planet.



The new map shows that the composition of Mars is much more complicated than what we thought. For example, while many salts formed after Martian clays, there are some salts that are presumed to be older than some of the clays.&nbsp;



“The evolution from lots of water to no water is not as clear cut as we thought, the water didn’t just stop overnight. We see a huge diversity of geological contexts, so that no one process or simple timeline can explain the evolution of the mineralogy of Mars. That’s the first result of our study. The second is that if you exclude life processes on Earth, Mars exhibits a diversity of mineralogy in geological settings just as Earth does,” said Carter.



Video Credit: ESA



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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The history of Mars is much more complex than we thought

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Today's Video of the Day from the <a href="https://www.stowers.org/">Stowers Institute for Medical Research</a> describes how cavefish adapted to a sedentary lifestyle over tens of thousands of years. 



The experts found that the muscle metabolism of cavefish has been genetically reprogrammed over time. As a result, the animals have experienced major changes in their morphology and behavior. Despite these changes, however, the cavefish remain healthy and fit.



The research may provide new clues about the evolutionary consequences of prolonged physical inactivity in humans.&nbsp;



“It’s no surprise that people are moving less and less as technology has advanced,” said Rohner. “With cavefish, we have a unique system where we can study what might happen if people remained couch potatoes over very, very long periods of time.”



Video Credit: Stowers Institute for Medical Research



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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Cavefish are healthy despite their sedentary lifestyle

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Today’s Video of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> some of the most incredible waves in the world, as seen by Landsat satellites.



"With more than 370,000 miles of coastline on Earth, there are plenty of places where epic waves build up, curl over, and hurtle toward the shore.- much to the thrill of surfers," says NASA. "There are some places where these waves are so magnificent that they can be seen from space."



"With the broad perspective of satellites, we can see how these iconic waves develop into the world’s tallest, longest, fastest, and heaviest."



Video Credit: NASA Earth Observatory&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



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Satellites capture the world's biggest and fastest waves

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