Heat stress impairs animal cognition and heightens aggression across species
From southern pied babblers to dogs and chamois, heat waves are muddling animal minds, threatening survival, pollination, and public safety as climate change accelerates.
A growing body of research indicates that high temperatures significantly impair animal cognition and increase aggression across diverse species, including birds, mammals, fish, and insects. Studies involving southern pied babblers, zebra finches, and mice reveal that heat reduces learning ability and problem-solving skills, while aggression rises in dogs, chamois, and fish during hot weather. Impaired cognition threatens survival by reducing vigilance against predators and affecting pollination, with climate change expected to exacerbate these effects.
In the Kalahari Desert, where temperatures are rising twice as fast as the global average, female southern pied babblers struggle with basic navigational tasks during heat waves. Amanda Ridley, a behavioural ecologist at the University of Western Australia, co-authored a study showing that when temperatures reached 96 degrees Fahrenheit, the birds failed to distinguish between a predator, a genet, and a neutral wooden box. On cooler days, the birds quickly navigate around see-through barriers to reach food, but during heat waves, they stubbornly peck at the plastic walls. This loss of vigilance increases the risk of fatal predator attacks.
Cognitive impairments are also evident in Australian zebra finches and bumblebees. Elizabeth Derryberry, an evolutionary biologist at the University of Tennessee, observed zebra finches repeatedly pecking at see-through tubes rather than finding the opening to retrieve mealworms. Similarly, Emily Baird, a neuroscientist at Stockholm University, found that bumblebee learning success dropped from a majority to less than half when temperatures rose from 77 degrees Fahrenheit to 90 degrees Fahrenheit. This impairment threatens pollination services for crops such as tomatoes and blueberries.
Aggression levels also spike with heat, posing risks to both wildlife and humans. A 2023 study of nearly 70,000 dog bite reports in eight US cities found a 10 percent higher risk of bites on 90 degree Fahrenheit days compared to 60 degree Fahrenheit days. Clas Linnman, a neuroscientist at the University of Miami, noted that both humans and dogs likely become more irate at higher temperatures. A 2025 study from China further indicated that snakes and cats are more inclined to bite people when temperatures rise.
Wildlife studies confirm that territorial aggression increases as vegetation becomes scarcer. Research on chamois in the Italian Apennine Mountains showed that when temperatures rose from 54 degrees Fahrenheit to 64 degrees Fahrenheit, the animals exhibited heightened territorial behaviour and chasing. The study authors predict that chamois aggression will increase by 50 percent by 2080 due to climate change. Similar confrontational behaviour was observed in golden julie fish, which became more aggressive towards their reflections when water temperatures increased from 78 degrees Fahrenheit to 84 degrees Fahrenheit.
These cognitive and behavioural shifts threaten animal survival and ecological stability. With climate change making heat waves more common, the ability of animals to adapt behaviourally becomes critical. Ridley warns that the impacts of increased heat on animal minds may be underestimated, particularly in urban areas where temperatures are often higher. As heat stress muddles animal brains, the ripple effects through ecosystems and public safety remain a significant concern.
