During an episode of SciShow, host Hank Green explains why koalas (and other animals) hug trees. As science has discovered, it’s an efficient way for the adorable marsupials to stay cool while expending as little effort as possible.
By hugging trees, though, koalas can stay cool without losing water. When researchers took infrared pictures of the koalas hugging trees, they realized that the trees are, on average, about five degrees cooler than the surrounding air. They’re not sure why the trees are so much cooler, but they think it might have something to do with the groundwater the trees pull up through their trunks. But it might also just take longer for the trees to heat up after the cool of the night. By spreading as much of their bodies as possible against the trees, koalas are able to transfer away some of their heat, and can cool themselves down by as much as 68 percent. So yeah, hugging trees is adorable… also useful.