Monkeys falling from trees and baking barnacles: how heat is driving animals to extinction

With the number of very hot days rising as well as average temperatures, more and more animals are vulnerable. But while some species can adapt, others are seeing huge population declines

The residents of Tecolutilla, Mexico, knew the heatwave was bad when they heard the thuds. One by one, the town's howler monkeys, overcome with dehydration and exhaustion, were falling from the trees like apples, their limp bodies smacking the ground as temperatures sizzled past 43C (110F) in spring last year.

Those that survived were given ice and intravenous drips by rescuers. At least 83 of the primates were found dead in the state of Tabasco, though local veterinarians estimated hundreds throughout the region probably perished.