Aaron Schachter: Okay, so we know now what motivates diplomats. Here's a question: what motivates koalas? The cuddly supermodel of the animal world, when you see them, they're usually clinging to trees. Did you ever wonder why? Well, probably not. But some scientists in Australia did. A team of researchers from the University of Melbourne has just published a study that suggests koalas hug trees to keep cool. Michael Kearney is one of the study's co-authors.
Michael Kearney: One of the questions we wanted to ask about the koalas is "do they use behavior at all to regulate their temperature? Are they able to choose places in their trees that make them a bit more comfortable?"
Schachter: The team used a thermal camera to take pictures of a koala population on French Island, near Melbourne, on a particularly hot day.
Kearney: It was so obvious once we got those pictures back what the koalas were doing. They were putting their bottoms into the cool forks of these trees and dumping all their excess heat into the tree.
Schachter: The team watched the koalas seeking out lower branches and laying listless and flat along this surface to cool down. The fur on a koala's belly is thinner than the fur on their backs, so they push that part of their body against the tree as much as possible. The type of tree was also a deciding factor for where the koalas hung out.
Kearney: It turned out the acacia was the best one to be in for losing heat into the trunks, but they don't eat the leaves of the acacia trees, they only eat the leaves of the eucalyptus trees. So they were leaving their food tree to go into these non-food trees because, we think, for the very reason that they could dump heat more effectively into the trees on the hot days.
Schachter: Kearney predicts koalas will use this behavior more and more as climate change leads to more extreme heatwaves. Now don't you just want to go to Australia and hug a tree? Or a koala?