Bats, often overshadowed by birds in discussions of long-distance migration, are now starting to be recognized for their remarkable travel feats.&nbsp;



A new study by scientists at the <a href="https://www.ab.mpg.de/" target="_blank" rel="noreferrer noopener">Max Planck Institute of Animal Behavior</a> (MPI-AB) has provided unprecedented insights into the migration strategies of common noctule <a href="https://www.earth.com/news/bats-can-ramp-up-their-heart-rate-to-900-beats-per-minute/" target="_blank" rel="noreferrer noopener">bats</a>. 



Using advanced tracking technology, the researchers discovered that these small mammals exploit storm fronts to maximize their energy efficiency during migration.



<h2 class="wp-block-heading" id="h-high-tech-window-into-bat-behavior">High-tech window into bat behavior</h2>



“The sensor data are amazing!” said Edward Hurme, a postdoctoral researcher at MPI-AB and the Cluster of Excellence Collective Behavior at the <a href="https://www.uni-konstanz.de/en/" target="_blank" rel="noreferrer noopener">University of Konstanz</a>.&nbsp;



“We don’t just see the path that bats took, we also see what they experienced in the environment as they migrated. It’s this context that gives us insight into the crucial decisions that bats made during their costly and dangerous journeys.”



The team employed lightweight, intelligent tracking devices developed by MPI-AB engineers. These tags, which weighed just five percent of the bats’ body mass, recorded extensive data, including activity levels and air temperature, throughout the migration.&nbsp;



The data were transmitted via a long-range network that provided coverage across Europe.&nbsp;



“The tags communicate with us from wherever the bats are because they have coverage across Europe much like a cell phone network,” explained Timm Wild, who led the development of the ICARUS-TinyFoxBatt tag at MPI-AB.



<h2 class="wp-block-heading" id="h-unique-and-variable-bat-migration-path">Unique and variable bat migration path</h2>



The study focused on 71 common noctule bats during their spring migration, covering up to four weeks. Unlike the predictable corridors often seen in bird migrations, the noctule bats took varied routes, though all moved in a general northeast direction.&nbsp;



“There is no migration corridor,” said Dina Dechmann, a senior author from MPI-AB. “We had assumed that bats were following a unified path, but we now see they are moving all over the landscape in a general northeast direction.”



The research also revealed that noctules can travel nearly 400 kilometers in a single night, a record for the species. However, their migration differs significantly from that of birds.&nbsp;



“Unlike <a href="https://www.earth.com/news/how-do-migratory-birds-navigate-with-such-accuracy/" target="_blank" rel="noreferrer noopener">migratory birds</a>, bats don’t gain weight in preparation for migration,” Dechmann noted. “They need to refuel every night, so their migration has a hopping pattern rather than a straight shot.”



<h2 class="wp-block-heading" id="h-timing-migration-with-weather">Timing migration with weather</h2>



On some nights, the researchers observed a dramatic increase in departures, which Hurme likened to “bat fireworks.” This led the team to investigate the environmental triggers for these events.&nbsp;



They discovered that bats tended to leave when air pressure dropped and temperatures rose - conditions associated with approaching storms.&nbsp;



“They were riding storm fronts, using the support of warm tailwinds,” Hurme explained. The tags also showed that bats expended less energy on these nights, confirming that they harness wind support to power their flights.&nbsp;



“It was known that birds use wind support during migration, and now we see that bats do too,” he added.



<h2 class="wp-block-heading" id="h-implications-for-conservation">Implications for conservation</h2>



These findings have significant implications for bat conservation, particularly in mitigating the risks posed by <a href="https://www.earth.com/news/wind-turbines-are-displacing-bats-from-their-forest-habitats/" target="_blank" rel="noreferrer noopener">wind turbines</a>, a leading cause of bat mortality. “Before this study, we didn’t know what triggered bats to start migrating,” said Hurme.&nbsp;



He expressed optimism that further research could lead to systems capable of forecasting bat migration. Such systems could help wind farms adjust operations to reduce collisions. 



“We can be stewards of bats, helping wind farms to turn off their turbines on nights when bats are streaming through. This is just a small glimpse of what we will find if we all keep working to open that black box.”



<h2 class="wp-block-heading" id="h-further-research-is-needed">Further research is needed</h2>



Despite these breakthroughs, much remains unknown about the full migration cycle of noctule <a href="https://www.earth.com/news/migratory-bats-use-earths-magnetic-field-as-a-compass/" target="_blank" rel="noreferrer noopener">bats</a>, which spans approximately 1,600 kilometers annually. The study’s novel tracking technology marks an important step in uncovering the complexities of their behavior. 



“We are still far from observing the complete yearly cycle of long-distance bat migration,” Hurme acknowledged. “The behavior is still a black box, but at least we have a tool that has shed some light.”



By continuing to explore these mysteries, researchers hope to deepen their understanding of bat migration, paving the way for effective conservation strategies and contributing to a broader understanding of animal migration.



The study is published in the journal <a href="https://www.science.org/doi/10.1126/science.ade7441" target="_blank" rel="noreferrer noopener">Science</a>.



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Bats 'surf' the winds of storms during migration 

Bats, often overshadowed by birds in discussions of long-distance migration, are now starting to be recognized for their remarkable travel feats.&nbsp; A new study by scientists at the Max Planck Institute of Animal Behavior (MPI-AB) has provided unprecedented insights into the migration strategies of common noctule bats.  Using advanced tracking technology, the researchers discovered that these small mammals exploit storm fronts to maximize their energy efficiency during migration. High-tech window into bat behavior “The sensor data are amazing!” said Edward Hurme, a postdoctoral researcher at MPI-AB and...

In recent years, <a href="https://www.earth.com/news/genetic-analyses-help-shark-conservation-efforts/">shark</a> and ray populations have been increasingly threatened due to overfishing and other human activities. Over the past half a century, oceanic populations have decreased by a staggering 71 percent and one third of all sharks and rays are currently threatened with extinction. However, according to a new study led by <a href="https://www.sfu.ca/">Simon Fraser University</a> (SFU), better fisheries management and conservation can be highly effective in reversing these worrisome trends.



By analyzing trends in fishing pressure, fisheries management, and population status for all wide-ranging coastal shark and ray species living in the western Atlantic Ocean, the experts found that populations in the northwest Atlantic recovered significantly following the implementation of a U.S. fishery management plan in 1993. This recovery – achieved by comprehensive regulation, monitoring, and enforcement – has halted the decline of three species and six out of eleven species are clearly rebuilding at the moment.



For these species, a strong system of regulations had been put in place, including catch reporting requirements, aggregate- and species-specific quotas, and catch prohibitions for several species. These regulations are enforced by the U.S. Coast Guard and law enforcement agencies, and the government continues to closely monitor and assess fisheries, while adding new regulations when needed.



“Our findings provide hope, but are a microcosm of the wider problem faced by sharks and rays,” said study lead author Nathan Pacoureau, a postdoctoral research fellow in Ecology and Conservation at SFU. “Many shark and ray species range widely and successful conservation in one country can be undone by less regulated fishing areas outside those borders.”



However, the researchers emphasized that several populations of the same species had collapsed in the southwest Atlantic Ocean due to unrestrained fishing. Currently, the number of wide-ranging coastal species threatened with extinction is nearly four times lower in the northwest than in the southwest Atlantic.&nbsp;



“These sensitive species have very slow life histories and are often collateral damage of sustainable target fisheries for more productive species,”&nbsp;said study senior author Nicholas Dulvy, an expert in Marine Biodiversity and Conservation at SFU.



These findings highlight the urgent need for well-enforced governance and science-based limits on fishing in order to prevent population declines and reduce extinction risks for a variety of shark and ray species.



The study is published in the journal <a href="http://dx.doi.org/10.1073/pnas.2216891120">Proceedings of the National Academy of Sciences</a>.



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By <a href="mailto:andrei.ionescu5891@gmail.com">Andrei Ionescu</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer



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Shark populations are rebounding in the northwest Atlantic

In recent years, shark and ray populations have been increasingly...

Scientists have long pondered what drives crocodile evolution, and whether the climate or changes in sea levels are major factors in this evolutionary process. Now, a team of researchers from <a href="https://www.mcgill.ca/">McGill University</a> in Canada has found that, while changing temperatures and rainfall patterns had relatively little impact on the <a href="https://www.earth.com/news/crocodiles-have-not-changed-much-in-200-million-years/">crocodiles</a>’ gene flow during the past three million years, sea level changes during the Ice Age had a more significant impact.



“The American crocodile tolerates huge variations in temperature and rainfall. But about 20,000 years ago – when much of the world’s water was frozen, forming the vast ice sheets of the last glacial maximum – sea levels dropped by more than 100 meters. This created a geographical barrier that separated the gene flow of crocodiles in Panama,” explained study lead author José Avila-Cervantes, a research associate specializing in Genomics, Evolution, and Ecology at McGill.



According to the scientists, although crocodiles are very good swimmers, they are unable to travel long distances on land. By comparing the climate tolerance of living populations of American crocodiles (Crocodylus acutus) to the paleoclimate estimates for this region over the past three million years, the experts discovered that, since Caribbean and Pacific crocodile populations were isolated from each other during the Ice Age, they undergone different genetic mutations.



“This is one of the first times Ice Age effects have been found in a tropical species. It’s exciting to discover effects of the last Ice Age glaciation still resonate in the genomes of Pacific and Caribbean American crocodiles today,” said study senior author Hans Larsson, a professor of Biology at McGill.



“Discovering that these animals would have easily tolerated the climate swings of the Ice Age speaks to their resilience over geological time. Only humans in recent decades of hunting and land development seem to really affect crocodiles.”



These findings provide new insights into how environmental factors affect genetic evolution and thus where conservation efforts of specific crocodile populations in Panama should be focused.



The study is published in the journal <a href="http://dx.doi.org/10.1093/evolut/qpac006">Evolution</a>.



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By <a href="mailto:andrei.ionescu5891@gmail.com">Andrei Ionescu</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer



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Crocodile evolution was influenced by environmental factors

Scientists have long pondered what drives crocodile evolution, and whether...

Every year, an estimated one-third of the U.S. population uses DEET to protect themselves from the bites of insects such as <a href="https://www.earth.com/news/mosquitos-use-unbreakable-system-to-track-human-blood/">mosquitos</a> and ticks. DEET (N,N-diethyl-meta-toluamide) is the active ingredient in more than 120 different repellent products that come in the form of sprays, lotions and roll-ons, or impregnated materials such as towelettes and wipes. It is an important weapon in the fight against diseases, such as Zika, West Nile fever, dengue and malaria that are carried by mosquitos, and diseases such as Lyme and Rocky Mountain spotted fever that are spread by ticks.&nbsp;



Although DEET has been used effectively to keep these disease-bearing insects at bay since 1957, when it was first made available to the public, there are some issues with its use. It has an unpleasant odor that puts some people off, and its repellent effects do not last very long before it has to be reapplied. To be effective, it has to be applied at the correct concentration, and even then there are some people who have reported sensitivity, with symptoms such as rashes, skin irritation, numb or burning lips, nausea, headaches,&nbsp;and dizziness. DEET also has the property of damaging certain materials, including plastics.



Researchers in many laboratories have sought chemical alternatives to DEET, and to the other popular repellent, known as picaridin. Although some synthetic substances have shown promise, none has proved as effective as DEET or picaridin at disrupting a mosquito’s ability to locate humans. &nbsp;Francesca Dani, from the University of Firenze, Italy, and her colleagues, had some previous success using two plant-based natural repellents that they modified to extend the protective timespan beyond that of DEET. However, they still wished to improve on these products further.&nbsp;



In their new research, published in the American Chemical Society's <a href="http://dx.doi.org/10.1021/acs.jafc.2c05537">Journal of Agricultural and Food Chemistry</a>, Dani and her colleagues synthesized additional cyclic hydroxyacetals from inexpensive, commercially available carbonyls. The new cyclic compounds had pleasant, much fainter odors and were easier to dissolve in water, meaning they can be formulated without high concentrations of alcohol. Some were as effective as DEET and picaridin at repelling Asian tiger mosquitos, which have spread widely in the U.S. and carry diseases, including encephalitis, dengue and dog heartworm.&nbsp;



Like picaridin, these new formulations provided human volunteers with more than 95 percent protection from bites for at least eight hours, while DEET’s protection rapidly declined below that level after just two hours. Toxicity of some of the most active new compounds was comparable to or lower than that of the traditional repellents. Two hydroxyacetals were also less likely to cause immune reactions or to penetrate cell layers than picaridin.&nbsp;



According to the authors, an ideal skin repellent needs to have the following attributes: highest repellent activity at low dose; negligible acute or chronic toxicity for humans, animals, and the environment; negligible or faint and pleasant odor; non-greasy feeling on the skin; resistance to abrasion from clothing, evaporation, and absorption from the skin surface; should not wash-off from sweat or rain; and should be easy to formulate in a water medium.



During their research, the scientists assessed all these attributes and found that their specifically formulated cyclic acetals and hydroxyacetals have potential to tick most of the boxes and could be effective repellents. The researchers conclude that their compounds represent a new class of promising mosquito repellents that can compete favorably with DEET and picaridin in terms of efficacy and safety.



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By <a href="mailto:bosman@truewan.co.za">Alison Bosman</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer



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Chemists take a new approach to developing insect repellents

Every year, an estimated one-third of the U.S. population uses...

A recent study led by the <a href="https://www.st-andrews.ac.uk/">University of St Andrews</a> in Scotland has found that humans retain an understanding of gestures made by other great apes, such as chimpanzees, bonobos, or orangutans, even though we no longer use them ourselves. The identification of over 80 gestural signals that are shared across a variety of non-human apes provides the first evidence of intentional <a href="https://www.earth.com/news/pigs-lack-the-skills-for-referential-communication/">communication</a> outside human language.



The scientists tested humans’ understanding of the ten most common gestures employed by chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) using an online game in which over 5,500 participants were asked to watch 20 short videos of ape gestures and select the meaning of each gesture from four possible answers.&nbsp;



The results revealed that participants performed significantly better than expected by chance, correctly identifying the meaning of the gestures more than 50 percent of the time. Moreover, providing contextual information about what the apes were doing only marginally increased participants’ success rates in interpreting the meaning of the gestures.



While video playback experiments have traditionally been used to test human language comprehension in non-human primates, this experiment reversed the paradigm in order to assess humans’ ability to understand the gestures of our closest evolutionary relatives. While the results clearly show that we have a strong capacity of understanding these gestures, it is still unclear whether this ability is genetically inherited, or whether humans and other primates share an ability to understand meaningful signals due to their general intelligence, similar social types of interactions and goals, and physical resemblance.



“All great apes use gestures, but humans are so gestural – using gestures while we speak and sign, learning new gestures, pantomiming etc. – that it’s really hard to pick out shared great ape gestures just by observing people. By showing participants videos of common great ape gestures instead, we found that people can understand these gestures, suggesting that they may form part of an evolutionarily ancient, shared gesture vocabulary across all great ape species including us,” concluded lead author Kirsty Graham, a research fellow in Psychology and Neuroscience at St Andrews.



The study is published in the journal <a href="http://dx.doi.org/10.1371/journal.pbio.3001939">PLOS Biology</a>. In addition, people can take a quiz version of the experiment <a href="https://research.sc/participant/login/dynamic/505CF355-CEF5-44ED-B2F1-2CBA484BD2FA">here</a>.&nbsp;



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By <a href="mailto:andrei.ionescu5891@gmail.com">Andrei Ionescu</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer



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Humans can understand the gestures of other great apes

A recent study led by the University of St Andrews...

Birds make use of a range of different mating systems to maximize their reproductive output. Ninety percent of bird species are monogamous, meaning that they have a single partner during a <a href="https://www.earth.com/news/plastic-additives-reduce-breeding-success-of-corals/">breeding</a> season. Partnerships may last only the time it takes to raise the chicks, or they may last a lifetime, as in the case of swans and geese. Having two parents sharing the work in this way reduces the load on each parent and is considered the most effective way of ensuring chick survival.



However, a small percentage of birds are polygamous. This means that a bird will have two or more partners of the opposite sex at the same time, and parents will not share equally in chick-rearing duties. In the case where a male can monopolize a group of females, this is called polygyny. He will protect and fertilize all the females, but will play no part in brood rearing. Where a female mates with several males (polyandry), she leaves each male to brood and rear the chicks alone, while she seeks out more breeding opportunities.&nbsp;



Scientists do not know why these different mating systems have evolved. They assume that each system maximizes the reproductive output of birds in different environmental circumstances, but this has not been proven. In a new study, an international team led by scientists from Bath university has analyzed the genomes of 150 bird species, spanning all the major bird families and from locations across the world, and has come up with a novel explanation for the evolution of polygamy in birds.&nbsp;



The researchers measured the levels of heterozygosity in the genomes of the birds. This refers to the extent of differences between the genes inherited from a bird’s mother and from its father. Greater heterozygosity is an indication of increased genetic diversity, which is important for bird populations to be able to adapt to changing environmental circumstances. But when the researchers estimated the levels of genetic diversity across each species, there was no evidence that polygamous species were any more diverse than monogamous species.



They also looked at the frequency of gene mutations in each species and whether these mutations affected the production of the proteins they coded for, or whether they were “silent”. The former, called non-synonymous polymorphisms, are often detrimental to the individual, whereas silent mutations are not expressed and are generally harmless.



The results, published in the journal <a href="http://dx.doi.org/10.1093/evolut/qpac010">Evolution</a>, showed that, relative to the number of silent mutations, the polygamous bird species had significantly fewer potentially damaging mutations that changed the coding sequences for proteins.&nbsp;



Kees Wanders, PhD student at the <a href="https://www.bath.ac.uk/">University of Bath</a> and first author of the paper, explained the significance of this result: “Species evolve through natural selection, where harmful mutations are removed from the population in the long term because individuals with the mutation don’t survive long enough to breed, or individuals with beneficial adaptations survive for longer. However, species also evolve through sexual selection, where evolution is shaped by individuals competing for access to mates, so that only the most desirable characteristics are successfully passed down to offspring.”



“This research suggests that sexual selection aligns with natural selection in birds, so that harmful mutations are removed more efficiently in polygamous populations, where sexual selection is particularly strong.”



Previous studies on fruit flies (Drosophila melanogaster) in the laboratory have also identified genetic differences that occur in male and female flies that are polygamous, in comparison with those that are monogamous. These genetic changes are not necessarily beneficial to the females, but appear to serve the interests of the males.



“There are many different theories about why polygamy evolved in these [animal] species, but we’ve found the first evidence that it increases the efficiency of natural selection by rooting out harmful mutations and avoiding the effects of inbreeding," said Wanders. "It’s been previously observed by others in the lab in fruit flies, but this is the first time it’s been observed in wild populations of birds.”



“I had a hypothesis that in polygamous species, where individuals can’t easily find a mate and have to travel further to find a breeding partner, that this would mean there would be more genetic diversity in these species. However, we were surprised to find there was no evidence for this - instead we found that these species had fewer harmful mutations," said study co-author Dr. Araxi Urrutia.



“Despite this apparent evolutionary advantage, most birds tend to stick together to raise their chicks because it gives their offspring a better chance of survival.”



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By <a href="mailto:bosman@truewan.co.za">Alison Bosman</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer



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Polygamous birds carry fewer harmful genetic mutations

Birds make use of a range of different mating systems...

Researchers at <a href="https://duke.edu/">Duke University</a> have discovered that glassfrogs make themselves transparent by hiding most of their red blood cells in their liver. According to the experts, this strategy allows the frogs to attain transparency when they are the most vulnerable.



"There are more than 150 species of known glassfrogs in the world, and yet we’re really just starting to learn about some of the really incredible ways they interact with their environment," said study co-lead author Jesse Delia.



"Transparency in animals is a complex form of camouflage involving mechanisms that reduce light scattering and absorption throughout the organism," wrote the study authors.



"In vertebrates, attaining transparency is difficult because their circulatory system is full of red blood cells (RBCs) that strongly attenuate light. Here, we document how glassfrogs overcome this challenge by concealing these cells from view."



The northern glassfrog Hyalinobatrachium fleischmanni is only a few centimeters in length and is most active at night, when the frogs are better able to blend with the surrounding landscape. During the day, glassfrogs become transparent to protect themselves while they sleep.



“When glassfrogs are resting, their muscles and skin become transparent, and their bones, eyes and internal organs are all that’s visible,” said study co-first author Carlos Taboada. “These frogs sleep on the bottoms of large leaves, and when they’re transparent, they can perfectly match the colors of the vegetation.”



The researchers explained that in vertebrates, attaining transparency is difficult because their circulatory system is full of red blood cells that strongly attenuate light. Glassfrogs are some of the only terrestrial vertebrates that can achieve transparency.&nbsp;



“If these frogs are awake, stressed or under anesthesia their circulatory system is full of red blood cells and they are opaque,” explained Delia. “The only way to study transparency is if these animals are happily asleep, which is difficult to achieve in a research lab. We were really banging our heads against the wall for a solution.”



"Using photoacoustic imaging to track RBCs in vivo, we show that resting glassfrogs increase transparency two- to threefold by removing ~89% of their RBCs from circulation and packing them within their liver," wrote the study authors.



Photoacoustic microscopy (PAM) involves shooting a safe laser beam of light into tissue, which is converted into sound waves to create biomedical images of the molecules.&nbsp;



“PAM is the ideal tool for non-invasive imaging of red blood cells because you don’t need to inject contrast agents, which would be very difficult for these frogs,” explained Professor Junjie Yao.&nbsp;



“The red blood cells themselves provide the contrast, because different types of cells absorb and reflect different wavelengths of light. We could optimize our imaging systems to specifically look for red blood cells and track how much oxygen was circulating in the frog’s bodies.”



“The primary result is that whenever glassfrogs want to be transparent, which is typically when they're at rest and vulnerable to predation, they filter nearly all the red blood cells out of their blood and hide them in a mirror-coated liver - somehow avoiding creating a huge blood clot in the process,” said study co-author Sönke Johnsen. “Whenever the frogs need to become active again, they bring the cells back into the blood stream, which gives them the metabolic capacity to move around.”



The researchers said that this process raises questions about how the frogs can safely store almost all their red blood cells in their liver without clotting or damaging their peripheral tissues. They noted that one potential next step is to study this mechanism and how it could one day apply to vascular issues in humans.&nbsp;



“Our successful collaboration has been a great example of how multiple disciplines can jointly advance science in the most synergistic way,” said Professor Yao. “We are extremely excited about the future interactions between the biology and engineering teams. With all the strength on board, the sky is the limit.”



The study is published in the journal <a href="https://www.science.org/doi/10.1126/science.abl6620">Science</a>.



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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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Glassfrogs achieve transparency by hiding their red blood cells

Researchers at Duke University have discovered that glassfrogs make themselves...

On an uninhabited island in Alaska, scientists have discovered that wolves are preying on sea otters after nearly wiping out the local deer population. Researchers from <a href="https://oregonstate.edu/">Oregon State University</a> and the Alaska Department of Fish and Game believe this is the first case of <a href="https://www.earth.com/news/sea-otters-have-a-secret-ability-to-generate-heat/">sea otters</a> becoming the primary food source for a land-based predator.



"Sea otters (Enhydra lutris) and wolves (Canis lupus) are two apex predators with strong and cascading effects on ecosystem structure and function. After decades of recovery from near extirpation, their ranges now overlap, allowing sea otters and wolves to interact for the first time in the scientific record," wrote the study authors.&nbsp;



The research was focused on Pleasant Island, which is located near Glacier Bay about 40 miles west of Juneau. In this region, sea otters were wiped out from fur trade hunting in the 1800s and 1900s.&nbsp;



Sea otters are now legally protected under the Marine Mammal Protection Act (MMPA). They were reintroduced to the Pleasant Island area in the 2000s, and wolves were introduced in 2013.



"After wolf colonization, we quantified shifts in foraging behavior with DNA metabarcoding of 689 wolf scats and stable isotope analyses, both revealing a dietary switch from Sitka black-tailed deer (Odocoileus hemionus), the terrestrial in situ primary prey, to sea otters," wrote the study authors.



"Here we show an unexpected result of the reintroduction and restoration of sea otters, which became an abundant marine subsidy for wolves following population recovery. The availability of sea otters allowed wolves to persist and continue to reproduce, subsequently nearly eliminating deer."



The researchers determined that in 2015, deer made up 75 percent of the wolves' diet, while sea otters made up 25 percent. By 2017, the wolves were primarily feeding on sea otters, while deer made up only seven percent of their diet. This pattern continued through the end of the study period in 2020.



“Sea otters are this famous predator in the near-shore ecosystem and wolves are one of the most famous apex predators in terrestrial systems,” said study co-author Professor Taal Levi. “So, it’s pretty surprising that sea otters have become the most important resource feeding wolves. You have top predators feeding on a top predator.”



“The thing that really surprised me is that sea otters became the main prey of wolves on this island,” said study co-author Gretchen Roffler. “Occasionally eating a sea otter that has washed up on the beach because it died, that is not unusual. But the fact that wolves are eating so many of them indicates it has become a widespread behavior pattern throughout this pack and something that they learned how to do very quickly.



“And from the work we are doing investigating kill sites, we are learning that wolves are actively killing the sea otters. So, they aren’t just scavenging sea otters that are dead or dying, they are stalking them and hunting them and killing them and dragging them up onto the land above the high tide line to consume them.”



The study is published in the journal <a href="https://www.pnas.org/">Proceedings of the National Academy of Sciences</a>.



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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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Clash of the top predators: wolves are eating sea otters

On an uninhabited island in Alaska, scientists have discovered that...

Each year, humpback whales migrate from warmer, temperate waters to the icy Antarctic to gorge themselves on <a href="https://www.earth.com/news/arctic-krill-can-distinguish-night-from-day-even-in-polar-winter/">krill</a>. These small, shrimp-like crustaceans are rich in nutrients and in the southern summer they become so abundant that the whales’ journey is well rewarded. The frigid waters become so crowded with krill that they were once considered an unlimited source of food, especially in the light of the removal of more than 2 million baleen whales from the Southern Ocean during the 20th century.



However, as with most ecosystems, the components of the Antarctic food webs are interconnected and none of them is inexhaustible. There is no surplus of krill, especially as whale populations have shown recovery and as global warming begins to change the Antarctic ice sheets.



In new collaborative research led by scientists from the <a href="https://www.ucsc.edu/">University of California, Santa Cruz</a>, the rate of pregnancy in a population of humpback whales was determined over an eight year period (2013 to 2020). Biopsy samples taken from the whales found off the West Antarctic Peninsula were used for genetic analysis, and to determine the levels of hormones, particularly progesterone. The results, published in the journal <a href="http://dx.doi.org/10.1111/gcb.16559">Global Change Biology</a>, indicate that the proportion of females that were pregnant varied considerably each year over the research period.&nbsp;



When the researchers linked the pregnancy rates to the abundance of krill in the waters of the West Antarctic Peninsula, they found that more females were pregnant in years following seasons of krill abundance. In 2017, after a year in which krill populations flourished, 86 percent of the female humpbacks were pregnant. However, in 2020, following a year in which krill populations were less successful, the pregnancy rate plummeted to only 29 percent.&nbsp;



Humpback whales only feed in the Southern Ocean for a few months of the year, and the females fast for most of the rest of the time, even while they are pregnant and nursing calves. This means that the nutrient and energy boost obtained from feeding on thousands of tons of krill during the brief summer visits to the Antarctic, is critical for reproductive success.&nbsp;



According to lead author Logan Pallin, the study demonstrates for the first time the link between population growth and krill availability in Antarctic whales.



“This is significant because, until now, it was thought that krill were essentially an unlimited food source for whales in the Antarctic,” said Pallin. “Continued warming and increased fishing along the Western Antarctic Peninsula, which continue to reduce krill stocks, will likely impact this humpback whale population and other krill predators in the region.”



Professor Ari Friedlaender noted that the Western Antarctic Peninsula is experiencing some of the fastest climatic warming of any region on the planet. Winter air temperatures have risen significantly since the 1950s, and the annual sea ice extent is, on average, 80 days shorter than four decades ago. These conditions are likely to affect the survival of krill populations negatively.



“Krill supplies vary depending on the amount of sea ice because juvenile krill feed on algae growing on sea ice and also rely on the ice for shelter,” Friedlaender said. “In years with less sea ice in the winter, fewer juvenile krill survive to the following year. The impacts of climate change, and likely the krill fishery, are contributing to a decrease in humpback whale reproductive rates in years with less krill available for whales.”



In recent decades, people have found uses for krill as a food source and medicinal treatments, and there is now a commercial fishery operating in the waters off the West Antarctic Peninsula. The total global harvest of krill from all fisheries is about 150–200,000 tons a year, though only a small percentage of this is for human consumption. The majority is utilized as fish food in aquaculture, bait, and livestock and pet food. Krill oil and enzymes are also used in various medicinal treatments.



Study co-author Chris Johnson is the global lead of the World Wide Fund for Nature’s Protecting Whales &amp; Dolphins Initiative. He said this research shows that highly precautionary management measures are needed to protect all Antarctic marine life that depends on krill for its survival, including blue, fin, humpback, minke, and southern right whales, as well as other krill predators such as penguins, seabirds, seals, and fish. &nbsp;



Furthermore, understanding how climate-mediated variation in prey availability influences humpback whale population dynamics is critical for focused management and conservation actions, particularly in light of changing temperatures in the Antarctic.&nbsp;



“This information is critical as we can now be proactive about managing how, when, and how much krill is taken from the Antarctic Peninsula,” added Pallin. “In years of poor krill recruitment, we should not compound this by removing krill from critical foraging areas for baleen whales.”



“Krill are not an inexhaustible resource, and there is a growing overlap between industrial krill fishing and whales feeding at the same time,” Johnson said. “Humpback whales feed in the Antarctic for a handful of months a year to fuel their annual energetic needs for migration that spans thousands of kilometers. We need to tread carefully and protect this unique part of the world, which will benefit whales across their entire range.”



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By <a href="mailto:bosman@truewan.co.za">Alison Bosman</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer



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Humpback whale reproduction is linked to krill abundance

Each year, humpback whales migrate from warmer, temperate waters to...

Common,European,Adder,(vipera,Berus)

By using a large genomic dataset, and cutting-edge computer modeling technology, a team of researchers led by the <a href="https://www.helsinki.fi/en">University of Helsinki</a> in Finland has managed to recently reconstruct the evolutionary tree of a major group of <a href="https://www.earth.com/news/modern-snakes-evolved-from-just-a-few-surviving-species/">snakes</a>, Elapoidea, an extremely diverse group of snakes spread all over the world, and including some of the deadliest known species. Moreover, the experts discovered an entirely new family within this group, consisting of four or five species found in the Levant region and in Eastern and Northeastern Africa.



Among the myriad snakes roaming the Earth, the elapoid snakes are some of the richest and diverse groups, consisting of over 700 species divided into several families. These snakes evolved in the early Cenozoic era (so-called “the Eocene”), around 50 to 45 million years ago. Currently, this group encompasses some of the most dangerous and deadly snake species, such as mambas and cobras, as well as several harmless yet bizarre species like the African shovel-nose snakes, or the venomous burrowing asps that can bite without opening their mouths.



By generating a gigantic genomic dataset of nearly 4,600 genes and using micro- and nano-computed tomographic scans for several elapoid snake species, the researchers managed to shed more light on the emergence and development of this important group.&nbsp;



“We estimate that Elapoidea originated in the early Eocene and rapidly diversified into all the major lineages during this epoch. Ecological opportunities presented by the post-Cretaceous-Paleogene mass extinction event may have promoted the explosive radiation of elapoid snakes,” the authors explained.



In addition, they also identified a new Afro-Asian family of snakes, the Micrelapidae, which is a rare event in Vertebrate Biology, occurring usually once a century. Until now, four or five species have been included in this family, all of them living in Eastern and Northeastern Africa and the Levant region.



“Snakes are not just diverse, but they are very important ecologically. The venomous snakes are important medically as well.&nbsp;What would happen if the knowledge on the evolution and classification of such an important group were in tatters?” said study lead author Sunandan Das, a doctoral student in Wildlife Biology at Helsinki.



“Everything would then get seriously impeded: From communication among scientists to research into the evolution of venom, venom delivery systems etc., from understanding the tempo and mode of the evolution of a big chunk of the global snake diversity to popular scientific work on such group. Until now, this has exactly been the case with elapoid snakes - they are a textbook example of ‘ancient, rapid radiation’ and, as such, a tough nut to crack,” he concluded.



The study is published in the journal <a href="https://doi.org/10.1016/j.ympev.2022.107700">Molecular Phylogenetics and Evolution</a>.



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By <a href="mailto:andrei.ionescu5891@gmail.com">Andrei Ionescu</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer



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Diverse group of snakes has a new evolutionary tree

By using a large genomic dataset, and cutting-edge computer modeling...

Alzheimer’s disease is a common neurodegenerative disorder which mostly affects older humans, leading to memory loss, confusion, and forgetfulness. However, a new study published in the <a href="https://doi.org/10.1111/ejn.15900">European Journal of Neuroscience</a> has found evidence that other species of animals may also suffer from this debilitating condition. 



By conducting postmortem studies on 22 odontocetes, or toothed whales – a group of cetaceans included <a href="https://www.earth.com/news/dolphins-have-accents-that-vary-by-region/">dolphins</a>, porpoises, and other species of whales possessing teeth – the experts discovered hallmarks of Alzheimer’s disease in the brains of three species of dolphins found stranded along the Scottish coast.



The scientists examined specimens from five species: Risso’s dolphins, long-finned pilot whales, white-beaked dolphins, harbor porpoises, and bottlenose dolphins. “Critically, we examined the whole brains to provide lesion (abnormality) profiles using more markers of Alzheimer’s disease,” said study senior author Mark P. Dagleish, an expert in Anatomic Pathology at the <a href="https://www.gla.ac.uk/">University of Glasgow</a>.



The analysis revealed that three aged dolphins - a long-finned pilot whale, a white-beaked dolphin, and a bottlenose dolphin – presented brain lesions associated with Alzheimer’s disease in humans. More specifically, these animals seemed to have accumulated phospho-tau and glial cells and formed amyloid-beta plaques, or the clumping of a protein found in the brains of humans suffering from this disease.



According to Dagleish, these findings are&nbsp;“the closest anyone has been able to show that any animals develop the Alzheimer’s disease-associated lesions spontaneously,” which scientists thought could only develop in humans.&nbsp;However, while the similar neuropathology of the aged dolphins and humans with Alzheimer’s suggests that these marine mammals have a susceptibility to the disease too, a clear diagnosis could only be made if clear cognitive deficits are also identified – which is of course impossible in postmortem studies.



“The simultaneous occurrence of amyloid-beta plaques and hyperphosphorylated tau pathology in the brains of odontocetes shows that these three species develop AD-like neuropathology spontaneously. The significance of this pathology with respect to the health and, ultimately, death of the animals remains to be determined. However, it may contribute to the cause(s) of unexplained live-stranding in some odontocete species and supports the ‘sick-leader’ theory whereby healthy conspecifics in a pod mass strand due to high social cohesion,” the authors concluded.



—



By <a href="mailto:andrei.ionescu5891@gmail.com">Andrei Ionescu</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer



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Dolphins may also suffer from Alzheimer’s disease

Alzheimer’s disease is a common neurodegenerative disorder which mostly affects...

Pheasants are more likely to be killed by predators in unfamiliar areas, according to a study led by the <a href="https://www.exeter.ac.uk/undergraduate/">University of Exeter</a>. The experts note that most animals know the central areas of their home ranges better than the edges.



For the investigation, the researchers tested the cognitive abilities of more than 100 captive-reared pheasant chicks. The birds were then tagged and released into the wild.&nbsp;



During a six-month study period, about 40 percent of the pheasants were killed by predators, which were primarily foxes.&nbsp;



The results show that the pheasants were far more likely to be killed near the edge of their range. The researchers say this was due to inexperience in these areas, because other birds that knew the same spots well were not likely to die there.



“For pheasants, experience within an area is much more important for predicting whether they are killed by predators than how dangerous the area is itself,” said study lead author Dr. Robert Heathcote.



“Ambush predators like foxes are quite habitual in their hunting behavior, so local pheasants may learn particular locations where foxes prefer to stalk their prey or lie in wait."



“Another explanation is that, with time, pheasants might gain more knowledge about the fastest and safest escape routes should they be attacked."



“Our study suggests this might cause pheasants to evolve better spatial memory, allowing them to expand the region that they have detailed knowledge about.”



Before their release, the birds were tested on two kinds of spatial memory by using a maze and a memory task. Ultimately, the researchers found that chicks with greater cognitive abilities grew up to have a larger range.



“One of the tasks we presented the chicks was to learn to navigate through a carefully designed maze to test for navigation-related spatial cognition including spatial reference memory," said study co-author Dr. Mark Whiteside.



“The ability to remember locations such as sites for foraging, drinking and refuge could explain why individuals that performed well on this task had larger home ranges after their release into the wild."



“Their performance in these tests that were administered when the birds were just a few weeks old went on to predict their chance of being killed by foxes months later.”



The team was able to establish the cause of death by using a novel reverse-GPS tracking system developed by Professor Sivan Toledo of Tel-Aviv University and Dr. Yotam Orchan of Hebrew University of Jerusalem. The high-precision system enabled the team to determine the exact timing, location, and cause of death among tagged birds.



“Our findings show that basic spatial abilities, revealed by tests in mazes, relate to real-world space use in the wild and, crucially, affect the survival of individuals in the face of predation,” said study co-author Dr. Joah Madden.



“We demonstrate that knowing about an area helps pheasants stay alive, and this means that these cognitive abilities can be shaped by natural selection. We now understand a bit more about how cognitive abilities can evolve.”



The research, which was funded by the European Research Council, is published in the journal <a href="https://www.nature.com/natecolevol/">Nature Ecology and Evolution</a>



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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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Pheasants are most vulnerable in unfamiliar territory

Pheasants are more likely to be killed by predators in...

According to a new study published in the <a href="https://www.apa.org/pubs/journals/xge/">Journal of Experimental Psychology</a>, adolescent <a href="https://www.earth.com/news/chimpanzees-use-surprisingly-complex-vocal-sequences/">chimpanzees</a> exhibit similar risk-taking behaviors as human teenagers, but they may be less impulsive than their human counterparts. These findings shed more light on the age-old nature versus nurture debates regarding whether adolescents take more risks due to biological predispositions or environmental influences.



“Adolescent chimpanzees are in some sense facing the same psychological tempest that human teens are,” said study lead author Alexandra Rosati, an associate professor of Psychology and Anthropology at the <a href="https://umich.edu/">University of Michigan</a>. “Our findings show that several key features of human adolescent psychology are also seen in our closest primate relatives.”



The scientists conducted two tests involving food rewards with 40 wild-born chimpanzees in Congo. In the first test, adolescent and adult chimpanzees had to choose between two containers in a gambling task. While one container was filled with peanuts – a food that chimps somewhat like – the other contained either a cucumber slice, which the apes dislike, or a banana slice (their favorite food). The animals could “play it safe” and get the peanuts, or take a chance for the coveted banana at the risk of ending up with the cucumber.&nbsp;



The chimps’ emotional reactions and vocalizations were recorded, and saliva sample were collected for tracking their hormonal levels. During several reiterations of the experiment, adolescent chimpanzees took the risky option more often than the adult ones, but had similar negative reactions when receiving the unwanted cucumber.



In a second test – modeled after the famous “marshmallow test” initially conducted with human children – chimpanzees could receive a slice of banana immediately or wait for one minute to get three slices, thus showing an ability for delayed gratification. In this case, both adolescent and adult chimps choose the greater delayed reward. By contrast, human teens tend to be more impulsive than adults, and are more likely to take the immediate reward.



“Prior research indicates that chimpanzees are quite patient compared with other animals, and our study shows that their ability to delay gratification is already mature at a fairly young age, unlike in humans,” Rosati explained. Thus, although risk-taking behavior in both adolescent chimpanzees and humans seem to be biologically ingrained, increases in impulses behavior may be specific to human teens.



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By <a href="mailto:andrei.ionescu5891@gmail.com">Andrei Ionescu</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer



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Young chimpanzees take risks like human teens

According to a new study published in the Journal of...

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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



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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



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.

Detecting mercury contamination with the tap of a finger

[sendtonews key="LvS8v8bp9z-2564889-12187" 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.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?

[sendtonews key="X0f6OHYoI4-2310561-12187" 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 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



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.

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

[sendtonews key="e4ZG0Jawp3-2374785-12187" type="single"] Astronomers at Johns Hopkins University have created...

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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 



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.

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



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.

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



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.

The province of Zaragoza in northeast Spain

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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



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.

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



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.

The Pyrenees Mountains in southwest Europe

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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



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.

Two distant planets may be "water worlds"

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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



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.

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



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.

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



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.

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



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.

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



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.

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



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.

Satellites capture the world's biggest and fastest waves

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> describes why satellite images and measurements of our planet have become "essential to our survival, offering a new outlook of our world."&nbsp;



Rising sea levels pose one of the biggest societal threats associated with climate change. According to ESA, satellite altimeter missions such as Copernicus Sentinel-6 are essential in monitoring global and regional changes in sea level.



"Unbeknown to many, the island of Crete, Greece, plays an important role in the Copernicus satellite altimetry constellation and on an international stage," reports ESA.



"Satellite altimetry data have to be continuously monitored at the ESA’s Permanent Facility for Altimetry Calibration where different techniques have pioneered the use of transponders to provide the best measurements to validate satellite altimeters in space soon after launch."



Dr. Craig Donlon explains that, by understanding planet Earth through satellite measurements, we are able to find evidence of change.&nbsp;



Video Credit: European Space Agency&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

Satellites have become essential to our survival

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