Animals

Carly Kay is the Fall 2025 science writing intern at Science News. She holds a bachelor’s degree in communication from the University of California, Santa Barbara and a master’s degree in science communication from the University of California, Santa Cruz. More

In a single year, one polar bear can leave roughly 300 kilograms of prey for other animals to dine on. Altogether, the carnivores provide 7.6 million kilograms of carrion for scavengers throughout the Arctic, researchers estimate.

The findings, reported October 28 in Oikos, highlight the crucial role these apex predators play in feeding a vast array of species and hints at the way that food web might be shaken as climate change warms the Arctic, endangering polar bear populations. More

Citations

E.K. Francispillai, S.M. Dietsch and L.J. Chapman. Effects of temperature on fish aggression and the combined impact of temperature and turbidity on thermal tolerance. Journal of Thermal Biology. Vol. 125, October 2024, 103987. doi: 10.1016/j.jtherbio.2024.103987.

H.M. Choi et al. Temperature, crime, and violence: a systematic review and meta-analysis. Environmental Health Perspectives. Vol. 132, October 2024, 106001. doi: 10.1289/EHP14300.

S. Pappas. How heat affects the mind. Monitor on Psychology. Vol. 55, June 2024, p. 42.

N.A.R. Jones, J. Newton-Youens and J.G. Frommen. Rise and fall: increasing temperatures have nonlinear effects on aggression in a tropical fish. Animal Behaviour. Vol. 207, January 2024, p. 1. doi: 10.1016/j.anbehav.2023.10.008. 

T. Dey, A. Zanobetti and C. Linnman. The risk of being bitten by a dog is higher on hot, sunny, and smoggy days. Scientific Reports. Published online June 15, 2023. doi: 10.1038/s41598-023-35115-6.

P. Krapf et al. Global change may make hostile – Higher ambient temperature and nitrogen availability increase ant aggression. Science of the Total Environment. Vol. 861, February 25, 2023, 160443. doi: 10.1016/j.scitotenv.2022.160443.

A. Xu et al. Monkeys fight more in polluted air. Scientific Reports. Published online January 12, 2021. doi:10.1038/s41598-020-80002-z.

K.E. Bissell and K.K. Cecala. Increased interspecific aggression between Appalachian stream salamanders at elevated temperatures. Freshwater Science. Vol. 38, December 2019, p. 834. doi: 10.1086/705995.

G. Greenberg. The effects of ambient temperature and population density on aggression in two inbred strains of mice, mus musculus. Behaviour. Vol. 42, January 1972, p. 119. doi: 10.1163/156853972X00130.

R.M Berry and C.E. Jack. The effect of temperature upon shock-elicited aggression in rats. Animal Learning and Behavior. Vol. 23, November 1971, p. 341. doi: 10.3758/BF03336141. More

Toastier fall weather might cause migrating monarch butterflies to wing it and change their flight plans, starting the countdown toward death. 

Eastern monarchs captured during their autumn migration and exposed to warm temperatures in the lab came out of their usual reproductive hiatus, evolutionary biologist Ken Fedorka and colleagues report August 12 in Royal Society Open Science. Breaking that hiatus means the butterflies will likely die sooner than they normally would.

“Once you decide to go reproductive, your clock starts ticking,” says Fedorka, of the University of Central Florida in Orlando. More

A mysterious disease has been turning sea stars into goo since 2013. Now, there’s a leading suspect behind the killings — a bacterium called Vibrio pectenicida, researchers report August 4 in Nature Ecology & Evolution. Knowing the identity of the killer could help scientists protect both captive and wild populations of sea stars.

The disease, known as sea star wasting disease, is characterized by twisted arms, lesions and rapid death. One of the worst hit species is the sunflower sea star (Pycnopodia helianthoides), which lost almost 91 percent of its population — over a billion individuals — to repeated outbreaks in 2015, 2018 and 2023. This decline has consequences for ocean ecosystems, as sunflower sea stars are predators that keep sea urchin populations in check. In their absence, sea urchins have mowed down kelp forests, which absorb atmospheric carbon dioxide and support fish, otters, sea lions and other animals.  More

Aaron Tremper is the editorial assistant for Science News Explores. He has a B.A. in English (with minors in creative writing and film production) from SUNY New Paltz and an M.A. in Journalism from the Craig Newmark Graduate School of Journalism’s Science and Health Reporting program. A former intern at Audubon magazine and Atlanta’s NPR station, WABE 90.1 FM, he has reported a wide range of science stories for radio, print, and digital media. His favorite reporting adventure? Tagging along with researchers studying bottlenose dolphins off of New York City and Long Island, NY. More

Add a little-known species of assassin bugs to the list of animals that can fashion and wield tools. And true to their name, the insects use that tool to draw their prey into an ambush, researchers report May 12 in Proceedings of the National Academy of Sciences.

Found in Thailand and China, Pahabengkakia piliceps is a species of predatory insects called assassin bugs that has a taste for the region’s stingless bees. When researchers at Xishuangbanna Tropical Botanical Garden in China began studying the assassin bugs in 2021, they became intrigued by how P. piliceps hunt. While lying in wait at a hive’s entrance, the assassin bugs use their front legs to proficiently pick off bees that fly by. More

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