Animals

A mysterious disease that has plagued sea stars for more than a decade may have met its match in the fjords of British Columbia.

Sunflower sea stars discovered thriving in the frigid waters suggest that cooler temperatures provide protection from sea star wasting disease, or SSWD. The finding, reported in the April Proceedings of the Royal Society B, is a valuable clue about what causes SSWD in the first place, researchers say.

Sea star wasting disease has stumped scientists since the first big outbreak emerged in 2013 off North America’s Pacific coast. “We initially thought it was a virus, but went back on that, because the data was either flawed or the results couldn’t be repeated,” says Ian Hewson, a marine ecologist at Cornell University who was not involved in the new study. His follow-up research into possible microbial or environmental causes has been inconclusive. More

Despite capturing hearts around the world, the wild axolotl — an aquatic salamander with feathery frills and a soft smile — faces extinction. Fortunately, for both axolotls and their fans, a new conservation method shows promise.

In captivity, axolotls abound as household pets and research subjects. But wild axolotls, endemic to a single lake in Mexico, are critically endangered due to degradation of their native wetlands, with only 50 to 1,000 individuals left in the wild. Introducing captive-bred axolotls to restored and artificial wetlands may be a promising option for conserving these charismatic critters, researchers report April 30 in PLOS One. More

Green sea turtles are adjusting their nesting habits in response to rising global temperatures. Individual females are laying their eggs earlier in the season to cope with warmer conditions, researchers report in the February Proceedings of the Royal Society B.

Scientists have long known that the sex of most turtle species is determined by incubation temperature — higher temperatures give life to females, and lower ones produce males. As climate change drives up temperatures, more females and fewer males are being born, potentially weakening populations. Extreme heat can also be lethal for the eggs.

Marine biologist Mollie Rickwood kneels next to a loggerhead turtle protected nest. The females dig themselves down in the sand using their flippers, then they dig a flask-shaped chamber where they lay eggs.Mollie Rickwood

To understand how turtles are adapting, conservation ecologist Annette Broderick and colleagues analyzed three decades of nesting data from around 600 tagged green turtles (Chelonia mydas) on the beaches of Northern Cyprus. The data included the number of successful hatchlings in each nest and temperatures during incubation. The team found that individual females nested earlier as temperatures rose, laying eggs just over six days earlier, on average, for each 1-degree-Celsius increase.

This is “the first time anyone looked at individual turtles and looked at how they’re changing,” rather than studying nesting behavior at a population level, says Broderick, of the University of Exeter in England. More

A small, rocky island off Iceland is home to the world’s largest breeding colony of Atlantic puffins.

When breeding season is in full swing, around 1.5 million adults pair up and nestle into burrows on the grassy seaside slopes above Heimaey island’s rocky cliffs.

Once chicks hatch, puffin moms and dads devote about six weeks to caring for their babies, bringing meals of small fish and fending off predators such as seagulls. By late August or early September, the pufflings are mature enough to live on their own. Over four to five weeks, throngs of young birds head off to sea. Their instinct is to head for the open ocean, where they will spend most of their lives. They leave in the dark of night to hide from predators, guided by the moon.

Puffin parents care for immature pufflings until they can fly on their own. The downy fluff around the neck of this puffling (right) indicates it’s not yet ready to fledge.Rachel Bennett/iStock/Getty Images Plus

But sometimes fledglings lose their way. Heimaey’s only town got electricity about a century ago. Ever since, dazzled by night lights or swept along in stiff sea breezes, some young puffins have taken a wrong turn — toward town.

Light pollution affects wildlife in perilous ways, disrupting crucial activities from pollination to mating. Some creatures, like these Atlantic puffins (Fratercula arctica), lose their orientation and can’t find their way to the ocean. Some could be attacked by predators; others might starve. Fortunately for these pufflings, the residents of Heimaey have taken a hands-on approach to addressing the problem. More

Like rolling into a gas station during a road trip, whale sharks use oil and gas rigs as a pit stop during their migrations of thousands of kilometers across the oceans. The human-made structures attract marine life — including the sharks’ favorite snack: plankton. But experts worry that this lure could put the endangered behemoths at risk of ship strike or chemical pollution.

Satellite tracking of whale sharks off the coast of western Australia shows how oil and gas platforms influence the movements of these gentle giants, marine ecologist Ben D’Antonio and colleagues report January 18 in Diversity and Distributions. “As they migrate across the ocean, they are stopping over and moving between features to presumably grab an easy meal before continuing with their migration,” says D’Antonio, of the Australian Institute of Marine Science (AIMS) and University of Western Australia in Perth. More

If your city is getting rattier, climate change may be partially to blame.

In an analysis of 16 cities around the world, those that saw the biggest temperature rises over the years also had more rat complaints over time, researchers report January 31 in Science Advances. Increased urbanization was also connected with more rat reports. The results suggest that higher temperatures may make rats — and the diseases they can spread — even harder to keep at bay. More

Landscapes in Southeast Asia once thought to stifle biological evolution may instead stoke its fires.

Karst ecosystems have been referred to as arks of biodiversity, a term that highlights their biological richness but also implies they merely preserve ancient lineages. These landscapes, with their isolated caves, cliffs and sinkholes, were thought to shelter species from extinction without contributing much to evolution.

But the discovery over the past several years of nearly 200 gecko species in such regions reveals that karsts are far from stagnant. “They’re not museums, but centers of speciation,” says evolutionary biologist Lee Grismer of La Sierra University in Riverside, Calif.

Some geckos from the Cyrtodactylus genus, like this newfound one from Cambodia, are uniquely adapted to thrive in the karst landscapes in Southeast Asia. Their specialized bodies allow them to cling to sheer rock faces.L. Lee Grismer

When Grismer first explored Myanmar’s karst landscapes in 2017, the richness of life hidden within the limestone towers and caves left him stunned. During a 19-day expedition, these ancient rock formations, rising abruptly from the surrounding farmland, revealed geckos so distinct and unexpected that his team identified 12 new species.

Since then, Grismer and his colleagues have ventured into similar formations across Southeast Asia, delving into the evolutionary secrets they harbor. In early 2024, an expedition to western Cambodia uncovered three new species of bent-toed geckos and a slender gecko — all detailed in upcoming papers — bringing the number of gecko species he has described to around 185. “The biodiversity in these landscapes is just off the charts,” Grismer says.

The gecko discoveries highlight this dynamism. Many karst-dwelling geckos belong to Cyrtodactylus, the third largest vertebrate genus in the world with close to 400 species described so far. Geckos of this genus discovered by Grismer and his team are among the most recently evolved members of their groups. They exhibit unique adaptations, such as elongated limbs, larger eyes and flatter heads, that enable them to cling to sheer rock faces, much like expert climbers.

Researchers discovered the Sanpel Cave bent-toed gecko, Cyrtodactylus sanpelensis, in a limestone cave in Myanmar. It was hiding under water running down a stalactite, says evolutionary biologist Lee Grismer. “This has never been observed before,” he says.
L. Lee Grismer

Grismer likens the karst formations to islands in an archipelago. Each formation, he says, serves as an evolutionary microcosm, producing species entirely distinct from neighboring karsts. “Species are coming from completely different species groups and different times throughout history.”

The true extent of gecko diversity in the karsts remains unknown. Grismer and his colleagues have surveyed only about 20 percent of the formations in western Cambodia, and he plans to return there and to Myanmar in 2025. “It wouldn’t surprise me if there are another 200 species out there.” More

“Forever chemicals” are pervasive, and researchers have in recent years been ringing the alarms about the negative impacts on human health. But humans aren’t the only animals to be concerned about.

Freshwater turtles in Australia exposed to per- and polyfluoroalkyl substances, or PFAS, experienced changes to their metabolic functions, environmental biochemist David Beale and colleagues report in the Dec. 15 Science of the Total Environment. “We found a whole range of biomarkers that are indicative of cancer and other health problems within reptiles,” says Beale, of the Commonwealth Scientific and Industrial Research Organisation in Dutton Park, Australia. More