Heat waves make animals stupid and aggressive | Knowable Magazine

Skip to content cookies to track usage and preferences." data-cookieaccepttext="I UNDERSTAND" data-cookiedeclinetext="Disable Cookies" data-cookiepolicytext="Privacy Policy"><br>1932

LAYOUT MENU<br>Insert PARAGRAPH<br>Insert IMAGE CAPTION caption full caption right caption left caption center<br>Insert SIDEBAR WITH IMAGE Position LEFT Position RIGHT Position CENTER Position FULL Some Placeholder Text">Standard CREDIT: NAME Economist Name Institution Name">Q&A expert<br>Insert SIDEBAR NO IMAGE Position LEFT Position RIGHT Position CENTER Position FULL Some Placeholder Text">Standard CREDIT: NAME Economist Name Institution Name">Q&A expert<br>Insert YMAL WITH IMAGES Position LEFT Position RIGHT<br>Insert YMAL NO IMAGES Position LEFT Position RIGHT<br>Insert NEWSLETTER PROMO<br>Insert IMAGE CAROUSEL Position FULL Position CENTER 1 Slide 2 Slides 3 Slides 4 Slides 5 Slides 6 Slides 7 Slides<br>Insert PULLQUOTE Position LEFT Position RIGHT<br>Insert VIDEO CAPTION full width center

LAYOUT MENU

CREDIT: SUNNU REBECCA CHOI

Studies are documenting how heat influences behavior and learning in a variety of animals.

Living World<br>They call it stupid hot for a reason: Heat muddles animal brains<br>As temperatures rise, some creatures pick fights while others struggle to learn. The consequences of these behavioral changes may ripple through ecosystems.<br>By Marta Zaraska 05.19.2026<br>Facebook<br>Bluesky<br>Twitter<br>LinkedIn<br>WhatsApp<br>Reddit<br>Flipboard<br>Email<br>Print<br>Republish

Support sound science and smart stories<br>Help us make scientific knowledge accessible to all<br>Donate today

On a blazing hot day in South Africa, female southern pied babblers can’t think straight. The medium-sized black-and-white birds are trying to get at tasty mealworms behind a see-through barrier. On cooler days, the birds can quickly figure out that all they have to do is go around the small wall of plastic. But when the mercury goes up, the birds just keep stubbornly pecking at the barrier.<br>That experiment is part of a growing body of research showing that animals get their minds muddled during heat waves. When it’s hot outside, birds struggle to learn, dogs bite more often, goat-like chamois pick fights. This is bad news not just for those who get on Fido’s toasted nerves. If the animals can’t stay alert enough to find food or avoid predators, their chances of survival go downhill, says Amanda Ridley, a behavioral ecologist at the University of Western Australia who coauthored the pied babbler study.<br>YOU MAY ALSO LIKE

Living World<br>Abracadabra! How magic can help us understand animal minds

Food & Environment<br>A warmer planet, less nutritious plants and … fewer grasshoppers?

Food & Environment<br>As the climate changes, plants must shift their ranges. But can they?

With climate change making heat waves more common, such cognitive impairments across the animal kingdom could ripple through entire ecosystems, putting already fragile species at greater risk. If pollinators forget which flowers to visit, crops and wild plants may fail. If birds can’t find food as easily, their young may not survive. And on a warming planet, a sharp mind is particularly vital. “A changing climate means that your ability to behaviorally adapt is even more important,” Ridley says.<br>Hotheaded<br>There is plenty of evidence that animals are affected by heat. Birds, for example, spend less time looking for food and feeding their young; they even sing less. Instead, they’ll sit around for hours with wings spread to dissipate the heat, and pant with their beaks wide open. Some animals retreat to shade or hide in cool burrows — again, skipping meals. Bees, meanwhile, splash their faces with droplets of water midflight when the weather is sizzling. This way, “they get convective cooling for their brain,” says Emily Baird, a neuroscientist at Stockholm University.<br>Some of the first hints that hot temperatures can mess up minds, however, came from studies on humans. Back in the 1800s, Belgian astronomer Adolphe Quetelet noticed that violent crime in France peaked in the summer. Later studies linked high temperatures with gun violence, mental-health-related hospital admissions, suicide and gambling. When it’s hot, people have trouble making decisions, and their memory suffers. For students at schools without air conditioning, a school year just one degree Fahrenheit hotter reduces test scores by 1 percent, a study found.<br>Increasingly there’s evidence that other species may also be more aggressive when mercury shoots up. A 2023 study that combed through nearly 70,000 reports of dogs biting people across eight US cities, from Chicago to Baltimore, found that such incidents were more likely to happen on hot, sunny and smoggy days. The risk was 10 percent higher on a 90-degree day than on a 60-degree day — and not only because people are more apt to venture out for walks when the sun is shining (the researchers controlled for seasonal...