For animals like fish and insects that can’t control their body temperature, heat waves could be particularly damaging. “Changes in air temperature will affect brain temperature,” Baird says. A warmer brain could hinder nerve function and that, he says, “could affect sensation, memory and learning.”
The cross section shows a band of cells in the mouse hippocampus.
Credit: RAUNAK BASU / UNIVERSITY OF UTAH, SALT LAKE CITY
The cross section shows a band of cells in the mouse hippocampus.
Credit: RAUNAK BASU / UNIVERSITY OF UTAH, SALT LAKE CITY
When Baird and his colleagues Tried to teach bumblebees to associate sweet sucrose with the color blue and bitter quinine with yellow, most of the bees learned the trick at 77°, but less than half managed to do it at 90°. This alteration in cognition could mean trouble in the field: if insects forget which flowers to pollinate (in the case of bumblebees, including tomatoes and blueberries) or how to return home with nectar, not only pollinators sufferbut also human agriculture, says Baird.
The heat also appears to dangerously diminish the animals’ vigilance. In Ridley’s recent experiments, once the mercury in the Kalahari Desert reached 96° F, Pied babblers lost their ability to respond appropriately to predators. In their studies, the researchers lured the birds toward a mysterious shape covered in a sand-colored blanket, using worms as bait. Once a charlatan approached, the scientists would reveal what was hidden beneath: a stuffed cat-like carnivore called a genet, or a wooden box of similar size and color. The birds were afraid of the genet when temperatures were colder: they would scream, scan their surroundings or simply run away. But once it got warm, they behaved similarly whether they were facing the carnivore or the box. Ridley suggests this could translate into increased chances of fatal predator attacks as the heat increases, which could harm populations of babblers and other prey species.
These studies are not just abstractions. In the Kalahari, where southern babblers use their ingenuity to hunt for worms, temperatures are rising twice as fast like the world average. In tropical rivers, where male guppies search for mates, Heat waves are becoming longer and more intense.. It’s the same story across much of the planet: temperatures rise and animal thinking becomes strained, potentially putting species at risk. The effects may be magnified in certain areas. like citieswhich often have even warmer temperatures than non-urban areas. If anything, Ridley says, “we’re probably underestimating the impacts of increased heat on animals’ minds.”
This story originally appeared on Knowable Magazine.
