A team of researchers have recently witnessed behavior in the wild that could offer critical clues about how the endangered whale shark reproduces.&nbsp;



This surprising discovery, made by a research team off northwestern Australia, could be pivotal for the species’ conservation.&nbsp;



<a href="https://www.earth.com/news/whale-sharks-move-into-dangerous-territory-as-the-climate-warms/" target="_blank" rel="noreferrer noopener">Whale sharks</a>, recognized as the world’s largest fish, have long posed a challenge for scientists who strive to understand the details of their life cycles - particularly their mating rituals.&nbsp;



Given that whale sharks are currently listed as endangered, every insight into their reproductive strategies is essential for crafting effective measures to protect them.



<h2 class="wp-block-heading" id="h-collecting-data-on-whale-shark-behavior">Collecting data on whale shark behavior </h2>



At Ningaloo Reef, a <a href="https://whc.unesco.org/en/list/" target="_blank" rel="noreferrer noopener">UNESCO World Heritage Site</a> on the northwestern coast of Western Australia, annual expeditions have taken place each May from 2009 to 2024. This specific timeframe captures the peak period when whale sharks migrate to the region and aggregate in considerable numbers.&nbsp;



Scientists have used these field seasons to observe and collect data on the behaviors of whale sharks, hoping to uncover patterns that would illuminate everything from feeding habits to potential <a href="https://www.earth.com/news/fascinating-mating-behaviors-of-leopard-seals-revealed/" target="_blank" rel="noreferrer noopener">mating rituals</a>.



During the 2024 expedition, a research team documented a mature male whale shark engaging in what appeared to be following and biting behaviors toward a smaller female shark.&nbsp;



Although it remains unclear if this encounter culminated in mating, the new observations provide a rare glimpse into the courtship interactions of these elusive giants.



<h2 class="wp-block-heading" id="h-first-hand-accounts-of-unusual-behavior">First-hand accounts of unusual behavior</h2>



“Following and biting are common copulation behaviours in other species within the subclass of cartilaginous fish that the whale shark belongs to,” explained PhD candidate Christine Barry, a member of <a href="https://www.murdoch.edu.au/" target="_blank" rel="noreferrer noopener">Murdoch University</a>’s Harry Butler Institute and the <a href="https://www.aims.gov.au/" target="_blank" rel="noreferrer noopener">Australian Institute of Marine Science</a>.&nbsp;



Barry and her colleagues noted that these behaviors have been observed in several other cartilaginous fish, including various shark species. Such actions typically denote an attempt by the male to stabilize or secure the female’s position during mating.



“This is also consistent with previous reports by fishers recounting behaviours they’d observed out on the water of sexually mature males towards females at different aggregation sites,” Barry added.&nbsp;



These anecdotes, now supported by direct evidence, add weight to the idea that whale sharks’ mating rituals may mirror those of other large sharks.



<h2 class="wp-block-heading" id="h-piecing-together-mating-clues">Piecing together mating clues</h2>



The research team, led by Barry alongside Dr. Mark Meekan of the University of Western Australia, published their conclusions in the journal <a href="https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2024.1507072/full" target="_blank" rel="noreferrer noopener">Frontiers in Marine Science</a>.&nbsp;



According to Barry, it is unlikely that the encounter during this expedition resulted in a successful mating event. Nonetheless, the instance of following and biting strongly suggests that whale shark mating behavior follows a pattern akin to many other shark species.



By placing these newly documented behaviors in the broader context of whale shark biology, scientists can form hypotheses regarding the mating process of the species.&nbsp;



Additionally, the research group underscores that knowledge of how whale sharks court and reproduce can significantly boost conservation efforts, particularly as populations remain vulnerable.



<h2 class="wp-block-heading" id="h-avoidance-behavior-by-female-whale-sharks">Avoidance behavior by female whale sharks </h2>



Whale sharks, which can grow up to 12 meters or more in length, have a global distribution in warm temperate and tropical waters. Despite their widespread presence, many aggregation sites show an overwhelming number of males.&nbsp;



“At Ningaloo Reef, and many aggregation sites around the world, males outnumber females with a ratio of one female to three males,” Barry said. The reasons behind this imbalance have puzzled scientists for years.



“This could explain why female whale sharks may be avoiding aggregation sites. Particularly for juvenile female sharks, the energetic costs of unwanted attention from males could imply a reason for strong male biases,” Barry added.&nbsp;



Female whale sharks, particularly younger ones, might seek refuge in areas with fewer adult males to steer clear of the stress and energy demands associated with repeated courtship attempts.&nbsp;



This avoidance behavior could be a crucial factor influencing whale shark population structures at various aggregation points.



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



One pressing question is what these findings mean for managing whale shark populations worldwide. As an endangered species, whale sharks already face numerous challenges, including interactions with fisheries, <a href="https://www.earth.com/news/basking-sharks-are-exceptionally-vulnerable-to-ship-strikes/" target="_blank" rel="noreferrer noopener">vessel strikes</a>, and habitat degradation.&nbsp;



Understanding their mating behavior, including how males and females interact at aggregation sites, can aid biologists and policymakers in deciding how to protect critical habitats - such as identifying areas where females can avoid male-dominated gatherings.



The annual expeditions at Ningaloo Reef also serve as a model for studying whale sharks in their natural environment without relying on anecdotal sightings.&nbsp;



By systematically gathering data and applying scientific methods, researchers can more accurately identify patterns and track changes in whale shark behavior over time.



<h2 class="wp-block-heading" id="h-continuation-of-whale-shark-research">Continuation of whale shark research</h2>



This new information about potential mating interactions is just the latest in a series of findings by Christine Barry, Dr. Meekan, and other scientists at Murdoch University’s School of Environmental and Conservation Sciences and partner institutions.&nbsp;



Their previous studies have covered topics ranging from the impact of tourism on whale shark well-being to prey dynamics in waters frequented by these fish.



Moving forward, the researchers intend to broaden their focus to include additional observational and genetic studies, in hopes of confirming how often such pre-mating behaviors occur and what leads to successful reproduction.&nbsp;



In this way, the data gleaned at Ningaloo Reef and other aggregation sites may help scientists develop clearer conservation strategies tailored to the unique reproductive needs of whale sharks.



<h2 class="wp-block-heading" id="h-saving-the-largest-fish-in-the-sea">Saving the largest fish in the sea</h2>



The newly documented behaviors at Ningaloo Reef represent a pivotal step in unraveling one of the great mysteries of marine biology: how whale sharks reproduce.&nbsp;



While much remains to be learned about courtship and mating in these gentle ocean giants, the direct observations of following and biting offer valuable context for a species that has long eluded scientific understanding.



With further research, scientists hope to clarify whether female whale sharks avoid highly male-dominated sites as a means to reduce the stress and energy costs of unwanted attention.&nbsp;



Such knowledge could shape guidelines for <a href="https://www.earth.com/news/how-marine-protected-areas-boost-human-health/" target="_blank" rel="noreferrer noopener">marine protected areas</a> and responsible ecotourism that minimize disturbances to whale shark breeding practices.&nbsp;



Ultimately, uncovering the nuances of whale shark mating is a vital piece of the puzzle in ensuring the survival of these endangered animals for generations to come.



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Whale shark mating behaviors observed for the first time in the wild

A team of researchers have recently witnessed behavior in the wild that could offer critical clues about how the endangered whale shark reproduces.&nbsp; This surprising discovery, made by a research team off northwestern Australia, could be pivotal for the species’ conservation.&nbsp; Whale sharks, recognized as the world’s largest fish, have long posed a challenge for scientists who strive to understand the details of their life cycles - particularly their mating rituals.&nbsp; Given that whale sharks are currently listed as endangered, every insight into their reproductive strategies is...

Light pollution has evolved in color and severity over the past two decades, resulting in complex impacts on moths and other animals who rely on <a href="https://www.earth.com/news/plants-set-a-bedtime-alarm-that-helps-them-survive-the-night/">night</a> vision, according to a new study from the <a href="https://www.exeter.ac.uk/">University of Exeter</a>. 

The experts report that artificial lighting can have a subtle yet dramatic influence on the behavior of nocturnal animals. 

To investigate, the researchers analyzed how various types of lighting affect the vision of moths, and the birds that eat them. In particular, the study revealed that elephant hawkmoth vision is enhanced by some types of lighting and disrupted by others. At the same time, the birds that hunt moths were found to see better under almost any type of lighting.

"Modern broad-spectrum lighting allows humans to see color more easily at night," said Dr. Jolyon Troscianko. "However, it is difficult to know how these modern light sources affect the vision of other animals."

"Hawkmoth eyes are sensitive to blue, green and ultraviolet, and they use this color vision to help find flowers just like bees, but at incredibly low light levels – even under starlight."

"Moths are also vitally important pollinators - accounting for a similar proportion of pollination as bees – so we urgently need to investigate how lighting affects them."

According to Dr. Troscianko, his team used animal vision modeling to calculate the ability of moths to see flower colors, and of birds to see camouflaged moths under a wide range of natural and artificial lighting.

“Artificial lights designed for human vision lack the blue and ultraviolet ranges that are key to moth color vision, and under many conditions will block the moth’s ability to see any colors at all," said Dr. Troscianko.

“This could make it more difficult for them to find and pollinate wildflowers, and for them to find suitable spots to camouflage them from predators."

"Conversely, bird vision is much more robust, meaning artificial light will help them to find camouflaged moth prey, and will allow them to hunt later into the evening and earlier in the morning."

The researchers found that white lights with a greater blue component promote more natural color vision in moths, even though these light sources are known to be harmful to other species.

Moths are declining across Europe, especially nocturnal species, and there is a growing collection of evidence that supports a link with light pollution. The experts are calling for a "nuanced approach" to lighting to limit the amount and intensity of light where possible.

The research was funded by the Natural Environment Research Council.

The study 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

Light pollution may be driving the decline of moths

Light pollution has evolved in color and severity over the...

The unfortunate reality of the name "fur seals" comes from a time when these beautiful <a href="https://www.earth.com/news/flower-evolution-is-influenced-by-the-animals-that-visit/">animals</a> were seen mainly through the eyes of hunters looking to profit from their skins. In fact, fur seals were hunted so heavily that one species - the Guadalupe fur seal (Arctocephalus townsendi) was declared extinct in the late 18001. 

Thankfully, scientists sometimes make mistakes - 14 of the “extinct” fur seals were discovered on Guadalupe Island in 1950. Since the rediscovery of the Guadalupe fur seals, their numbers have continued to grow. 

Today, the IUCN estimates the Guadalupe fur seal population to be around 41,000 seals, and increasing by ten to eleven percent annually. So far, the only breeding location for the fur seals is their namesake - Guadalupe Island. 

A "haul out" colony, where the seals bask on shore and rest, was populated on San Benito Islands in the 1990’s. Now, researchers are announcing the formation of a new haul out colony, which is a good sign for the seals. The newest resting colony is on El Farallón de San Ignacio Island.

Study co-author Claudia Hernández-Camacho explained that the colony started with the observation of one adult in 2008 until today’s conditions,

“During our visits to El Farallón in 2020, we counted 492 individuals in January, and 771 in November. Most of the animals we have seen have been juveniles, and all have appeared to be in good body condition."

The scientists observing the seals initially thought it might be a fluke to see the seals on El Farallón, considering that the island is hot and dry and not typical for fur seals. They now suspect that the island is a prime feeding area, where the seals hunt their preferred food of squid. 

The good news is that all of these islands are protected land. The bad news is that the government of Mexico still classifies the seals as only occasional visitors to El Farallón and has no conservation plan in place for them yet. 

So far, the seal populations are growing slowly and the animals can be found as far away as the coast of Washington. The seals are still in a precarious position with only one breeding location. 

"Guadalupe fur seals have only one breeding colony, so the new haul-outs in the southern Gulf of California provide some good news. However, the new sites will need regular monitoring to document their growth and possible changes in body conditions, age and sex-composition, and breeding potential," said study co-author Andrew Trites. "This species escaped extinction once and remains vulnerable."

The study is published in the journal <a href="https://onlinelibrary.wiley.com/journal/17487692">Marine Mammal Science</a>.

---

By <a href="http://zachfitzner@yahoo.com">Zach Fitzner</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Guadalupe fur seals are on the mend

The unfortunate reality of the name "fur seals" comes from...

Human impacts now kill about 100 million sharks per year. An international team of researchers led by ecologist Erin Dillon recently focused a study on shark denticles to determine how <a href="https://www.earth.com/news/coral-reefs-could-completely-stop-growing-by-2054/">reef</a> communities have changed as a result of human activities. 

Sharks have microscopic scales called dermal denticles thar provide them with protection from abrasive surfaces. The team compared the abundance and variety of denticles from a Panamanian coral reef 7,000 years ago to those in reef sediments today.

Dillon began the research as an intern at the <a href="https://stri.si.edu/">Smithsonian Tropical Research Institute</a> (STRI), and is currently finishing her doctoral work at UC Santa Barbara.

"If you have ever petted a shark in an aquarium touch tank, denticles are the reason why shark skin is rough like sandpaper if you rub it in one direction yet smooth in the other direction. Sharks are essentially covered by millions of tiny teeth," explained Dillon.

Just like humans shed dry skin and dandruff, sharks shed their denticles, and they accumulate in marine sediments. The oldest shark denticles ever found - discovered in the Harding Sandstone of Colorado - are about 455 million years old.

STRI paleobiologist Aaron O'Dea uses data obtained from fossil- and modern coral reefs to reconstruct baseline conditions before human colonization. These reconstructions also help scientists understand how evolutionary processes change through time.

"Placoderms in the Paleozoic, and then marine reptiles in the Mesozoic, were larger and ate sharks," said O'Dea. "Placoderms ruled the oceans for around 70 million years and marine reptiles of the Mesozoic ruled for more than 100 million years."

"Sharks are only top predators now because extinction events preferentially took out other groups but allowed sharks to survive. Sharks seem to have remarkable evolutionary resilience and I was fascinated to work on a technique that would help us explore how sharks have fared more recently when humans step into the picture."

The team sampled material from a 7000-year-old fossilized reef in Bocas del Toro, Panama and from nearby modern Caribbean reefs. O'Dea asked Dillon to analyze the samples and look for shark denticles.

"What started as a three-month-long internship turned into a two-year stay in Panama and then expanded into part of my PhD thesis," said Dillon. "I've grown with this project as my role shifted from first exploring and processing the samples as an intern to leading the project, analyzing and interpreting the data, and spearheading the writing."

One week's worth of samples took about a year of lab work to recover and identify the denticles. 

"Finding the first denticles was thrilling," said Dillon. "They were beautifully preserved and abundant enough to provide insights into millennia-old shark communities."

Ultimately, Dillon found that denticle accumulation rates - which represent shark abundances - were over three times higher before humans began using marine resources in the region. While all types of denticles had declined over time, those found on commercially valuable sharks declined the most. 

Based on evidence from archaeological studies and historical records, Dillon determined that the steepest decline in shark abundance occurred in the late 20th century. 

"When the Spanish arrived in the Americas, they wrote fantastic accounts of seas swarming with sharks," said Dillon. "But these days we see very few sharks: we are lucky to see the occasional nurse shark."

"Our data show that sharks in Bocas del Toro have been depleted both by long-term harvesting, which accelerated in the second half of the 20th century, and by habitat degradation, which began even earlier with the expansion of banana cultivation and coastal development. There is so much land-based runoff from the coast today that in some locations it's like swimming through limeade."

&nbsp;

"Taken together, Erin's body of work shows that denticle assemblages can be used with care to help reconstruct past shark communities through time," said O'Dea. "Sharks are an integral part of ocean health and play important roles in the great diversity and functioning of coral reefs. Having empirical estimates of past shark abundances and community composition helps us frame our understanding of what is natural in the seas."

According to Dillon, the researchers hope to extend this method to other locations to examine broader geographic patterns of change in reef shark communities over long ecological timescales. 

"For example, we're currently reconstructing trends in denticle accumulation along Panama's Pacific coast over the last several thousand years using sediment cores. These baseline data will help us explore the causes and consequences of changes in shark abundance and functional diversity. Our work can also help tailor shark management goals to this local region."

The study is published in the journal <a href="https://www.pnas.org/">Proceedings of the National Academy of Sciences</a>.

---

By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Shark denticles reveal human impacts over centuries

Human impacts now kill about 100 million sharks per year....

In a new study from the <a href="https://www.exeter.ac.uk/">University of Exeter</a>, researchers have discovered that a vast seabird colony on Ascension Island creates a "halo" in which fewer <a href="https://www.earth.com/news/oceans-with-no-corals-will-have-half-as-many-types-of-fish/">fish</a> live. 

Located far from the mainland, the UK Overseas Territory of Ascension Island is home to tens of thousands of seabirds of various species. Some of these species, including frigatebirds, masked boobies and brown boobies, prey on flying fish. 

The experts have found that the numbers of flying fish are greatly reduced within a 90-mile radius of the island, which is a phenomenon that can only be explained by foraging seabirds.

Dr. Sam Weber is an expert in the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall.

"This study tells us a lot about large colonies of animals and how their numbers are limited," said Dr. Weber.

"These birds are concentrated at Ascension Island during the breeding season, and the intensity of their foraging is naturally highest near the island."

"As they use up the most accessible prey located near to the island, they have to travel increasingly long distances to feed, causing the 'halo' to expand outwards."

"Once individuals can't find enough food to break even with the energy they expend finding it, the colony stops growing.

Dr. Weber noted that human activities such as fisheries can interfere with this natural balance and have negative effects on populations of marine top predators like seabirds, even if they don't directly harm the birds.

"What was particularly surprising is the large scale of the footprint we found. It shows that Marine Protected Areas may need to be very large because some predators rely on prey stocks across a huge area."

The pattern of fish declines revealed by the study is known as "Ashmole's halo," named after British ornithologist Philip Ashmole, who first proposed a theory about this type of prey depletion about 60 years ago after visiting Ascension Island.

The study is published in the journal <a href="https://www.pnas.org/">Proceedings of the National Academy of Sciences</a>.

---

By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Seabirds create a "halo" of depleted fish

In a new study from the University of Exeter, researchers...

We often think of individual drivers of natural selection separately from each other. It’s easy to think of the big and bold examples - how male Irish elk or peacocks were driven to evolve elaborate decoration to attract mates, despite the inherent risks. <a href="https://www.earth.com/news/an-answer-to-the-mystery-of-sperm-evolution/">Evolution</a> is more complex than this though. 

Many factors work together to select "for" or "against" individual traits and the underlying suit of genes. In a new study led by Michael Moore of <a href="https://wustl.edu/">Washington University</a>, experts have investigated how different factors affect the color patterns of male dragonfly wings.

The researchers looked at the amount of pigment found in male dragonfly wings. It is believed that the primary purpose dragonfly wing colors is for mating. However, the scientists have now found that sex is not the only factor in wing color. 

Utilizing databases created by "citizen scientists" using iNaturalist and field guides, the experts were able to examine the amount of pigment found in dragonfly wings at different locations. The difference in pigments is important because, depending on the color, wings can increase in heat up to two degrees celsius, explained Moore.

As expected, the study authors found that dragonflies found in warmer locations tend to have less pigment on their wings, while those in cooler climates tend to have more. This seems to be an adaptation that keeps dragonflies from overheating. 

The study also revealed that in warmer years, dragonflies tended to have less wing color than those photographed on cooler years. Interestingly, female dragonfly wings do not change colors as much in response to temperature as those of males. 

Looking at climate change scenarios, the researchers note that we cannot expect male and female dragonflies to adapt in the same ways. One possibility is that as wing patterns change, it will become harder for female dragonflies to distinguish between members of their own species and different species, a potential problem for the survival of these fascinating insects.       

The study is published in the journal <a href="https://www.pnas.org/">Proceedings of the National Academy of Sciences</a>.

---

By <a href="http://zachfitzner@yahoo.com">Zach Fitzner</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Dragonfly wing colors driven by climate and sexual selection

We often think of individual drivers of natural selection separately...

Wisconsin currently hosts between 695 and 751 gray wolves, which is a major drop from a population of at least 1,034 <a href="https://www.earth.com/news/cougars-threat-yellowstone-elk/">wolves</a> last year, according to a new study from the <a href="https://www.wisc.edu/">University of Wisconsin-Madison</a>. 

The research suggests that about one-third of the population decline is due to hidden deaths in the wolf population that have resulted from relaxed legal protections.

On November 3, 2020, the United States Fish &amp; Wildlife Service officially removed the gray wolf from the federal Endangered Species list in the contiguous United States and Mexico. The new law became effective in January of 2021.

In the current study, the researchers found that 218 wolves were killed by licensed hunters during Wisconsin's first public wolf hunt. The experts report that the uncounted deaths of an additional 100 wolves may be attributed to something called cryptic poaching, where poachers hide evidence of illegal killings.

The overall loss of about 323 wolves represents a decline in Wisconsin's wolf population of between 27 and 33 percent between April 2020 and April 2021. 

The research has produced the first estimate of Wisconsin's wolf population since the public hunt in February. The hunt ended early after hunters exceeded the quota of 119 wolves within a few days. 

The researchers believe that the current population contains a maximum of 751 gray wolves, considering that they incorporated optimistic assumptions about population growth and low poaching rates in their computer models.

The population estimates will help the Wisconsin Department of Natural Resources (DNR) prepare for the next wolf hunt this fall.

"Although the DNR is aiming for a stable population, we estimate the population actually dropped significantly," said Professor Adrian Treves.

In previous studies from Professor Treves' lab, the team showed that wolf population growth declined in Wisconsin and Michigan when legal protections were relaxed, regardless of the number of wolves that were killed legally. 

The results of other studies suggest that when governments allow lethal management, poachers are inclined to kill more wolves because the relaxed policies signal that predators are less valued. The researchers took this into consideration when modeling the uncounted gray wolf deaths in Wisconsin since last November.

"During these periods, we see an effect on poaching, both reported and cryptic. Those wolves disappear and you never find them again," said Francisco Santiago-Ávila. "Additional deaths are caused simply by the policy signal, and the wolf hunt adds to that."

Without hunting, the researchers estimate that the population could recover in one to two years. The experts hope that the Wisconsin DNR and other states' natural resource agencies take advantage of their methods to develop a more complete assessment of the effect of new policies on predator populations.

"These methods and models are freely available to these agencies," said Karann Putrevu. "They should take advantage of the best available science to meet their stated goals."

The study is published in the journal <a href="https://peerj.com/">PeerJ</a>.

---

By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Wisconsin gray wolf population dropped by 30 percent in one year

Wisconsin currently hosts between 695 and 751 gray wolves, which...

We’ve all seen flies swarm to dung or dead animals to eat. Despite the difference in taste between the average fly and most people, the insects don’t eat just anything - their diet has to meet certain criteria. Like all animals, flies spend time seeking out foods that are tasty and <a href="https://www.earth.com/news/human-activity-crops-nutritious/">nutritious</a>. 

In a new study from <a href="https://www.yale.edu/">Yale University</a>, researchers have investigated the food choices of flies to determine what goes on in their brains while choosing between two menu items. 

The experts offered fruit flies (Drosophila melanogaster) two choices - a nutritious food laced with a bitter substance and a less nutritious, low-calorie option that tasted sweet. 

The team used neuroimaging to track neural activity as the flies made the choice between the high-calorie or tasty food.

"It depends on how hungry they are," explained study senior author Professor Michael Nitabach. "The hungrier they are, the more likely they will tolerate bitter taste to obtain more calories."

However, the experts report that the real answer to how flies make food choices is a little more complicated. The researchers explained that flies relay sensory information to a portion of their brain called the fan-shaped body, where signals are integrated, triggering what amounts to the insect version of an executive decision. 

The study revealed that patterns of brain cell activity in the fan-shaped body change when new food choices are introduced, and this controls the fly's decision over what food to eat.

The researchers took the study one step further by manipulating neurons in parts of the brain that feed into the fan-shaped body. By decreasing the activity of neurons that regulate metabolism, the scientists were able to force the flies to "decide" to eat the lower calorie food, even when very hungry. 

The reward systems in the brains’ of flies and humans are similar and this study relates to how Homo sapiens make food decisions as well. In this way, this finding could be used as a way to understand how hunger and eating behavior work in humans.

“The study provides a template to understand how it is that things like hunger and internal emotional states influence our behavior,” said Professor Nitabach.

The study is published in the journal <a href="https://www.nature.com/ncomms/">Nature Communications</a>.

---

By <a href="http://zachfitzner@yahoo.com">Zach Fitzner</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

How do flies decide what to eat?

We’ve all seen flies swarm to dung or dead animals...

In a new study from <a href="https://www.ucsc.edu/">UC Santa Cruz</a>, experts have discovered why pelagic red crabs are sometimes found stranded in staggering numbers outside of their range. 

The crabs have been known to wash up on the West Coast of the United States in the millions. The new study suggests that abnormal <a href="https://www.earth.com/news/oceans-with-no-corals-will-have-half-as-many-types-of-fish/">ocean</a> currents push the creatures out of their home range in Baja California.

Study lead author Megan Cimino is a biological oceanographer at the National Oceanic and Atmospheric Administration (NOAA) and UC Santa Cruz through the Institute of Marine Sciences Fisheries Collaborative Program.

In 2018, Cimino had biked past a pelagic red crab stranding on route to her office in Monterey, California. Years earlier, she had witnessed another stranding event in Southern California.

"At that time, I had no clue what a red crab was, what was going on, why they would be there," said Cimino. "But it was very clear something different was going on in the ocean - something unusual."

When she brought this to the attention of her colleagues, the team decided to investigate what was driving these unusual events. 

For months, the experts analyzed information from sources including oceanographic research surveys and citizen science programs to compile data about the recorded range of the red crabs and the occurrence of strandings from 1950 to 2019. 

Ultimately, the researchers found that the appearance of red crabs outside of their normal range correlated with the amount of seawater flowing from Baja California to central California. 

The evidence supports the idea that strong currents, and not warm water associated with Niño events, cause the red crab strandings.

The researchers used a regional ocean model of the California Current System, which was developed by scientists in the UC Santa Cruz ocean modeling group, to study the ocean currents that can push red crabs out of their range.

"What you're doing is putting a tracer - you could think of it like a dye - into a particular part of the ocean and then running the model backwards in time to see where that came from," said study co-author Michael Jacox.

Based on the results, the team created the southern source water index (SSWI), which shows how much water off the central California coast comes from south of the U.S.-Mexico border.

"It's that pathway of water that brings up some of these unusual species," said study co-author Ryan Rykaczewski. "It's not just the pelagic red crabs, even though those might be the most conspicuous species that we see on the coast."

According to the researchers, the red crabs represent a larger phenomenon that they can use the SSWI to better understand.

"The index could be used as a kind of early warning system about what the ocean state is that year and whether we're going to expect southern species in northern regions," said Cimino. "That can help us plan and manage and give expectations for bycatch or different fisheries."

The study is published in the journal <a href="https://aslopubs.onlinelibrary.wiley.com/journal/19395590">Limnology and Oceanography</a>.

---

By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Strong ocean currents push red crabs far out of their range

In a new study from UC Santa Cruz, experts have...

Flower evolution seems to be influenced by the various animals that visit, according to a new study from the <a href="https://www.tsukuba.ac.jp/en/">University of Tsukuba</a>. The researchers have proposed a new theory that trade-offs caused by different visitors play a central role in shaping floral <a href="https://www.earth.com/news/the-biodiversity-crisis-will-take-millions-of-years-to-recover-from/">diversity</a>.

When it comes to interactions between animals and flowers, some visitors are beneficial, like pollinators, while others can be detrimental. As a result, different selection pressures influence flower traits such as scent or color. 

"On the basis of this theory, you'd expect that flowers would mostly be visited by one particular group of pollinators," said study lead author Professor Kazuharu Ohashi. "But flowers often host many different visitors at the same time and flowers appear to meet the needs of multiple visitors. The question we wanted to answer is how this happens in nature."

In the case where a scent attracts one pollinator but deters another, the flower would attempt to accommodate the best pollinator. 

For example, diurnal bees and nocturnal moths can both pollinate goat willow, yet they prefer different smells. The researchers explained that balancing the demands of multiple visitors involves trade-offs.

The experts developed a conceptual framework to examine different types of trade-offs, as well as how flower evolution may be affected. Next, the team analyzed relevant studies to determine whether the research supported the proposed framework.

The researchers discovered a variety of strategies for mitigating trade-offs. In the case of goat willow, flowers produce different scents during the day and night, and therefore attract both pollinators. Furthermore, floral color can change to attract both bees and flies. 

All of the strategies that were mentioned by the researchers involved acquiring novel combinations of traits to attract, or deter, different visitors.

"Most flowers are ecologically generalized and the assumption to date has been that this is a suboptimal solution," said Professor Ohashi. "But our findings suggest that interactions with multiple animals can actually be optimized by minimizing trade-offs in various ways, and such evolutionary processes may have enriched the diversity of flowers."

The researchers predict that future studies will find that the structure of flower-visitor communities and the associated trade-offs have played critical roles in flower evolution.

"Identifying convergent adaptations to particular community contexts may help us to understand better the evolutionary link between diverse floral phenotypes and their visitors.'

The study is published in the journal <a href="https://onlinelibrary.wiley.com/journal/1469185x">Biological Reviews</a>.

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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

Flower evolution is influenced by the animals that visit

Flower evolution seems to be influenced by the various animals...

Climate change is increasing heat stress on humans, plants, and animals. Experts at the <a href="https://www.tum.de/en/">Technical University of Munich</a> set out to investigate the precise <a href="https://www.earth.com/news/temperatures-are-rising-unexpectedly-fast-on-the-tibetan-plateau/">temperatures</a> at which weather becomes dangerous for all of Earth's living organisms.

According to the study, the most optimal temperatures range from 17 to 24 degrees Celsius, or 62.6 to 75.2 degrees Fahrenheit.

"We have studied which temperatures are preferable and which are harmful in humans, cattle, pigs, poultry, and agricultural crops and found that they are surprisingly similar," said study co-author Professor Senthold Asseng.

The investigation showed that in weather conditions with high humidity, mild heat strain for humans begins at about 23 degrees Celsius, and at 27 degrees Celsius in low humidity. 

"If people are exposed to temperatures above 32 degrees Celsius at extremely high humidity or above 45 degrees Celsius at extremely low humidity for a lengthy period of time, it can be fatal," said Professor Asseng. 

"During extreme heat events with temperatures far above 40 degrees Celsius, such as those currently being observed on the U.S North West Coast and in Canada, people require technical support, for example in the form of air-conditioned spaces."

Professor Asseng points to a variety of strategies, including increasing natural shade from trees, to mitigate heat. Furthermore, cities and buildings can be designed with lighter, reflective roof and wall colors to reduce heat strain.

In cattle and pigs, heat strain occurs at 24 degrees Celsius with high humidity and at 29 degrees Celsius with low humidity, according to the study. 

The milk yield from cows can decrease by up to 20 percent when they are exposed to heat stress, and the fattening performance in pigs is also reduced. 

The comfortable temperature range for poultry is 15 to 20 degrees. Chickens were found to experience mild heat strain at 30 degrees Celsius. Beginning at a temperature of 37 degrees Celsius, chickens experience severe heat stress and lay fewer eggs. 

In addition, the experts report that heat stress reduces growth in cattle, pigs, chickens and other livestock, which means both lower yields and reproductive performance. 

"There are examples of evolutionary adaptations to warm weather in terrestrial mammals. Transylvanian naked chickens are more heat tolerant than other varieties of chickens because of a complex genetic mutation that suppresses feather growth. They are naturally air-conditioned because they lack feathers on their necks," explained Professor Asseng.

"In crops, the optimal temperature zone and temperature thresholds seem to be more diverse due to differences between species and varieties."

For example, cold-temperate crops such as wheat do better at cooler temperatures, while warm-temperature crops such as corn are sensitive to frost but can tolerate warmer temperatures. 

"By the end of the century, 45 to 70 percent of the global land area could be affected by climate conditions in which humans cannot survive without technological support, such as air conditioning. Currently, it's 12 percent," said Professor Asseng. 

In other words, up to 75 percent of the human population will be chronically stressed by heat in the coming decades. A similar increase in heat stress is expected for agricultural crops, livestock, and other plants and animals. 

"Genetic adaptation to a changing climate often takes many generations. The time available is too short for many higher forms of life. If current climate trends persist, many living things could be severely affected or even disappear completely from Earth due to temperature change."

The study is published in the journal <a href="https://www.thelancet.com/journals/lanplh/home">Lancet Planetary Health</a>.

---

By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

At what point does heat stress become dangerous?

Climate change is increasing heat stress on humans, plants, and...

Unrelated lizards in very different parts of the world have learned the same skills, despite evolving separately for hundreds of millions of years, according to a new study from the <a href="https://www.unsw.edu.au/">University of New South Wales</a>. 

The experts say their research shows that natural selection directs evolution toward the same common set of adaptive outcomes over and over again.

The study reveals that the Anolis lizards in the Caribbean and the Draco lizards in Southeast Asia communicate in the same way to defend their territories and attract mates. 

Males from both species perform elaborate dances, bobbing their heads with exaggerated movements. They also puff out their brightly colored dewlap, or throat fan, and even do some pushups.

Since the lizards occupy the same types of rainforest and grassland habitats, they also face the same communication challenges. Remarkably, they have evolved the same strategy to cope with the same selection problems, said study lead author Dr. Terry Ord of the UNSW School of Biological, Earth and Environmental Sciences.

"The surprise is that lizards in both groups have evolved remarkably similar displays for communication, but they also tailor the production of those displays according to the prevailing conditions experienced at the time of display," explained Dr. Ord.

"That is, increasing the speed or the length of time they spend displaying the movements as the viewing conditions deteriorate."

"Really there should be essentially innumerable ways these lizards could have adapted their displays to remain effective, and there is strong evolutionary predictions that would lead us to expect this as well."

According to Dr. Ord, the study shows that natural selection is driving similarities between different species. Formally, this is known as convergent evolution - the independent origin of similar adaptations - he explained.

"It seemed that these types of convergent, common adaptations are outcomes that would only really occur among species that are closely-related in some capacity."

"The reason for this is a bit complicated and it rests on the fact that adaptations build on characteristics that a species already possesses."

"So, the longer species have evolved independently of each other, the less likely they would evolve the same adaptive solutions if they were exposed to the same change in the environment."

What this study highlights, said Dr. Ord, is what many evolutionary ecologists have argued - that natural selection is an extremely powerful process that can override the "baggage" of past history to produce the same adaptations.

"So if arm-waving is the most effective solution to some change in the environment, then natural selection would ultimately lead to its evolution rather than a more subtle (less effective) modification to an existing vocal call."

"Evolutionary biologists are excited about convergent evolution because it gives us multiple examples of the same adaptation evolving time and time again in very different animals.?

"So it tells us what the challenges are faced by these animals and how they have solved it in terms of evolutionary adaptation."

Dr. Ord said the striking similarities in communication strategies under noisy conditions has evolved not only in lizards, but also among many insects, fish, frogs, birds and mammals.

"For example, increasing the volume of calls when there's lots of acoustic background noise, or extending the length of those calls or even vibrational signals by spiders and such."

"The fact that many other groups of animals have also evolved thesesame adaptive strategies is even more extraordinary."

The study is published in the journal <a href="https://onlinelibrary.wiley.com/journal/14610248">Ecology Letters</a>.

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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

Unrelated lizards evolved the same skills over millions of years

Unrelated lizards in very different parts of the world have...

There have been conflicting theories about what led to the extinction of mastodons and other elephants. One hypothesis is that prehistoric elephants and other mammalian megafauna were wiped out by the ravenous hunting of early humans as we spread across the globe. 

But now, a new study from the <a href="http://www.bristol.ac.uk/">University of Bristol</a> supports an entirely different conclusion. In collaboration with paleontologists at the Universities of Alcalá and Helsinki, the team carried out the most complex analysis to date on the rise and decline of elephants. 

The research delved into the evolution of 185 species over 60 million years by studying museum collections all over the world. 

“Most proboscideans over this time were nondescript herbivores ranging from the size of a pug to that of a boar. A few species got as big as a hippo, yet these lineages were evolutionary dead-ends. They all bore little resemblance to elephants," explained study co-author Dr. Zhang Hanwen.

Roughly 20 million years ago, when the Asian and African continents collided, proboscidean (elephant) evolution took a turn, by allowing ancestral elephants new areas to explore in Eurasia. Once out of Africa, the elephants evolved 25 times faster than their slowly evolving African ancestors. This led to a boom in elephant and elephant-like species in Eurasia. 

However, this boom wasn’t to last. The rapidly changing climate demanded changes just as quick in the evolution of creatures that were to survive. 

By 2.4 million years ago, extinction of prehistoric elephants and their relatives had peaked in Africa. Eurasia and the Americas soon followed at 160,000 and 75,000 years ago, respectively. 

These extinction time periods might let our ancestors off the hook - they don’t correlate with human expansions. Instead, it looks like climate may be the culprit. This isn’t to say that humans played no role, they certainly still hunted mastodons and other prehistoric elephants, they just may not be the main cause of extinction.    

"We didn't foresee this result. It appears as if the broad global pattern of proboscidean extinctions in recent geological history could be reproduced without accounting for impacts of early human diasporas. Conservatively, our data refutes some recent claims regarding the role of archaic humans in wiping out prehistoric elephants, ever since big game hunting became a crucial part of our ancestors' subsistence strategy around 1.5 million years ago," said study co-author Dr. Zhang Hanwen.

"Although this isn't to say we conclusively disproved any human involvement. In our scenario, modern humans settled on each landmass after proboscidean extinction risk had already escalated. An ingenious, highly adaptable social predator like our species could be the perfect black swan occurrence to deliver the coup de grâce."

The study is published in the journal <a href="https://www.nature.com/natecolevol/">Nature Ecology and Evolution</a>.

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By <a href="http://zachfitzner@yahoo.com">Zach Fitzner</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

What killed off prehistoric elephants and their relatives?

There have been conflicting theories about what led to the...

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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

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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



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.

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



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.

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 



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



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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

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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



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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

[sendtonews key="761m2QQvR1-2035772-12187" type="single"] Today’s Video of the Day from the...