{"id":841937,"date":"2026-08-03T13:57:11","date_gmt":"2026-08-03T13:57:11","guid":{"rendered":"https:\/\/www.newsbeep.com\/au\/841937\/"},"modified":"2026-08-03T13:57:11","modified_gmt":"2026-08-03T13:57:11","slug":"stupid-hot-heat-waves-are-making-animals-more-aggressive-forgetful-and-less-alert","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/au\/841937\/","title":{"rendered":"Stupid Hot: Heat Waves Are Making Animals More Aggressive, Forgetful and Less Alert"},"content":{"rendered":"

\"\"<\/a>Illustration: ZME Science.<\/p>\n

On scorching days in South Africa\u2019s Kalahari, female southern pied babblers can have trouble solving what should be a simple problem.<\/p>\n

A mealworm sits behind a transparent barrier. During cooler weather, the black-and-white birds soon work out that they must walk around the plastic to reach it. As temperatures climb, however, some females keep pecking directly at the barrier. They can see the food. They just struggle to abandon a response that is not working.<\/p>\n

That experiment is part of a growing body of research showing that animals get their minds muddled during heat waves. When it\u2019s 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\u2019s toasted nerves. If the animals can\u2019t stay alert enough to find food or avoid predators, their chances of survival go downhill, says Amanda Ridley<\/a>, a behavioral ecologist at the University of Western Australia who coauthored the pied babbler study.<\/p>\n

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\u2019t find food as easily, their young may not survive. And on a warming planet, a sharp mind is particularly vital. \u201cA changing climate means that your ability to behaviorally adapt is even more important,\u201d Ridley says.<\/p>\n

\"\"<\/a>A southern pied babbler. Image credits: Wiki Commons.<\/p>\n

Heat changes an animal\u2019s priorities<\/p>\n

Long before heat affects performance in an experiment, it changes how animals spend their time.<\/p>\n

There\u2019s plenty of evidence that animals are affected by heat. Birds, for example, spend less time looking for food<\/a> and feeding their young<\/a>; they even sing less<\/a>. Instead, they\u2019ll 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 \u2014 again, skipping meals. Bees, meanwhile, splash their faces with droplets of water midflight when the weather is sizzling. This way, \u201cthey get convective cooling for their brain,\u201d says Emily Baird<\/a>, a neuroscientist at Stockholm University.<\/p>\n

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<\/a>. Later studies linked high temperatures with gun violence<\/a>, mental-health-related hospital admissions<\/a>, suicide<\/a> and gambling<\/a>. When it\u2019s hot, people have trouble making decisions<\/a>, and their memory suffers<\/a>. For students at schools without air conditioning, a school year just one degree Fahrenheit hotter reduces test scores<\/a> by 1 percent, a study found.<\/p>\n

Increasingly there\u2019s 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<\/a> days. The risk was 10 percent higher on a 90-degree day than on a 60-degree day \u2014 and not only because people are more apt to venture out for walks when the sun is shining (the researchers controlled for seasonal effects in their data).<\/p>\n

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Still, the scientists were unable to determine whether dogs get more aggressive as it gets hot, or if cranky humans provoke more attacks. \u201cIt\u2019s likely that both humans and dogs get stressed and more irate at higher temperatures,\u201d said Clas Linnman, a neuroscientist at the University of Miami and a coauthor on the study.<\/p>\n

And it\u2019s not only dogs: A 2025 study out of China showed that many animals, including snakes and cats, are more inclined to bite people when it gets hot.<\/p>\n

Animals also seem to lose their cool with each other, especially if there is food involved. <\/p>\n

Scientists used binoculars and spotting scopes to spy on wild goat-like chamois that feed on protein-rich plants on the slopes of the Italian Apennine Mountains. More than 1,600 hours of observations over two summers revealed that when temperatures rose from 54 to 64 degrees Fahrenheit, vegetation grew scarcer, and chamois aggression in turn shot up<\/a>. The animals became territorial over patches of food, they assumed threatening postures, chased each other \u2014 attacks that, at times, escalated. The study authors predict that chamois aggression will go up 50 percent by 2080 due to climate change.<\/p>\n

The small tropical fish called a golden julie also gets confrontational in the heat. Ordinarily, when a golden julie is placed in front of a mirror, it sees its reflected image as a stranger and shows some hostility, raising its fin, for example. But if the normally 78-degree water is raised to a hot 84 degrees, the fish is more likely to get aggressive, and may bite and slap its tail against the mirror, as it tries to scare or attack the reflected image.<\/p>\n

Cognitive problems<\/p>\n

\"Guppy <\/a>Image via Unsplash.<\/p>\n

Heat waves can also hamper the ability of animals to learn, as Ridley and her colleagues observed with the southern pied babblers. In one of their experiments, the birds were presented with a simple wooden block with two holes drilled in it, each covered with a lid. If the bird pecked at the lid, it would rotate, revealing either an empty hole or a tasty mealworm (the babblers, Ridley says, \u201care highly motivated by mealworms\u201d). One lid was dark, and the other a lighter shade of the same color. During heat waves, the birds needed twice as many trials to learn that the mealworm was always hidden under the lid of the same shade.<\/p>\n

Another group of scientists tested zebra finches<\/a>, pretty Australian songbirds, and discovered that if temperatures are high, they too have cognitive problems. When figuring out how to get a mealworm out of a see-through tube with an opening at one end, they would just keep pecking on the tube, says study coauthor Elizabeth Derryberry<\/a>, an evolutionary biologist at the University of Tennessee, Knoxville. It\u2019s the bird equivalent of \u201cbanging your head against a brick wall,\u201d she says.<\/p>\n

Adding to the tally, several years ago researchers showed that when the heat is on, mice have trouble<\/a> finding their way around a maze and forget objects they\u2019ve seen the day before. More recently, researchers found that male guppies<\/a>, popular aquarium fish, also have trouble getting through a maze after spending several days in heat-wave-like 90-degree water, even if the prize for getting it right is a virgin female \u2014 which they tend to find particularly attractive.<\/p>\n

For animals such as fish and insects that can\u2019t control their body temperature, heat waves could be particularly detrimental. \u201cChanges in air temperature will affect brain temperature,\u201d says Baird. A hotter brain could hinder the functioning of nerves, and that, she says, \u201cmight affect sensing, memory and learning.\u201d<\/p>\n

When Baird and colleagues tried to teach bumblebees to associate sweet sucrose with the color blue<\/a> and bitter quinine with yellow, most of the bumblebees learned the trick at 77 degrees, but fewer than half managed to do so at 90 degrees. Such impaired cognition could spell trouble in the field: If the insects forget which flowers they should pollinate (in the case of bumblebees, these include tomatoes and blueberries) or how to get back home with nectar, not only will the pollinators suffer<\/a>, but human agriculture too, Baird says.<\/p>\n

Heat appears to dangerously diminish animal vigilance as well. In Ridley\u2019s recent experiments, once mercury in the Kalahari Desert reached 96 degrees Fahrenheit, pied babblers lost their ability to properly respond to predators.<\/a> In their studies, researchers lured birds toward a mystery shape covered in a sandy-colored blanket, using worms as bait. Once a babbler approached, the scientists would reveal what was hidden underneath: either a taxidermied cat-like carnivore called a genet, or a similarly sized and colored wooden box. The birds got scared of the genet in cooler temperatures \u2014 they\u2019d call out, scan their surroundings, or simply flee. But once it got hot, they behaved similarly whether they were facing the carnivore or the box. Ridley suggests that this could translate into higher chances of fatal predator attacks as heat rises, which could harm populations of babblers and other prey species.<\/p>\n

These studies are not just abstractions. In the Kalahari, where southern pied babblers use their wits to search for worms, temperatures are rising twice as fast<\/a> as the global average. In tropical rivers, where male guppies seek mates, heat waves are growing longer and more intense<\/a>. It\u2019s the same story across much of the planet \u2014 temperatures climb, and animal thinking becomes strained, potentially putting species at risk. The effects may be magnified in certain areas such as cities<\/a>, which often exhibit even warmer temperatures than non-urban areas. If anything, Ridley says, \u201cWe are probably underestimating the impacts of increased heat on animal minds.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"Illustration: ZME Science. On scorching days in South Africa\u2019s Kalahari, female southern pied babblers can have trouble solving…\n","protected":false},"author":2,"featured_media":841938,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[21021,266429,64,63,162053,170541,68,284094,8174,14240,414080,50438,128,414081,338],"class_list":["post-841937","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-animal-behavior","tag-animal-cognition","tag-au","tag-australia","tag-bumblebees","tag-chamois","tag-climate-change","tag-dog-bites","tag-ecology","tag-extreme-heat","tag-guppies","tag-heat-waves","tag-science","tag-southern-pied-babblers","tag-wildlife"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/841937","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=841937"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/841937\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/841938"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=841937"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=841937"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=841937"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}