Scientists alarmed after birds repeatedly fail simple test during heat waves: 'We're probably underestimating the impacts'

In South Africa's searing heat, female southern pied babblers seem to struggle to overcome a simple obstacle. 

On hot days, the birds do not go around a clear plastic barrier to get a mealworm. Instead, they keep pecking at the plastic, a behavior that suggests extreme temperatures may interfere with cognition.

What's happening?

Research increasingly suggests that heat waves can affect more than animals' physical comfort. According to Smithsonian Magazine, high temperatures may hinder learning, memory, and vigilance while also increasing the likelihood of aggression.

Among southern pied babblers, heat waves doubled the number of attempts needed to learn which lid on a box hid a mealworm. In Southern Africa's Kalahari Desert, once temperatures reached 96 degrees Fahrenheit, the birds stopped responding appropriately to a predator model and treated it much like a harmless box. Scientists are seeing similar patterns in other species as well.

Bumblebees had more trouble learning color-reward associations at 90 degrees than at 77, and chamois in Italy became more aggressive as temperatures climbed and food grew scarce. Smithsonian Magazine also cited a 2023 study that found the risk of dog bites was about 10% higher at 90 degrees than at 60 degrees.

Why does it matter?

The findings are troubling for wildlife, but they also have consequences for people.

If birds, bees, fish, and mammals cannot think clearly enough to find food, avoid predators, or navigate their surroundings, ecosystems become less stable. Humans rely on those ecosystems in countless ways.

Pollinators such as bumblebees support crops, including tomatoes and blueberries. If extreme heat makes it hard for them to keep track of rewarding flowers or find their way home with nectar, agriculture can suffer too.

Smithsonian Magazine reported that the Kalahari, where pied babblers depend on sharp instincts to survive, is warming at roughly twice the global average. In cities, which can be hotter still, the strain on animals — including pets — may be even greater. Rising heat does not just threaten animals physically; it may also erode the mental abilities they need to cope with the changing climate in the first place.

What's being done?

Researchers are paying close attention to how heat affects behavior, not just survival. That shift could help conservationists predict which species are most at risk during long, intense heat waves and design protections around those limits.

Cool habitats matter, and shade, access to water, and altering heat-trapping urban infrastructure can reduce stress on wildlife and pets alike. 

"A changing climate means that your ability to behaviorally adapt is even more important," said Amanda Ridley, a behavioral ecologist who worked on the study. "... We are probably underestimating the impacts of increased heat on animal minds." 

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