There’s a very cool reason behind this behaviour
The koala is one of the most famous tree huggers in the world. They’re almost always found clinging to a branch or nestled into the fork of a tree, and it turns out that this behaviour helps the cuddly marsupials to deal with Australia’s heat.
When the weather is cooler, koalas venture out onto leafy branches, but in summer they shimmy back down and get as close to the tree trunk as possible. Because of their thickness and the concentration of water-transporting tissues, these lower parts of the tree heat up slowly and can be several degrees cooler than the air around them, so hugging tight helps the animals to reduce their temperature and avoid overheating. On a hot day, a tree trunk is like the koala’s equivalent of an ice pack on the forehead, and it’s an efficient way of keeping cool because, unlike panting and licking their fur, it doesn’t lose any water.
Image: Eric Kilby/flickr