Koala bears aren't bears: They're marsupials. Koalas sleep up to 20 hours a day. Koalas are excellent swimmers. Koalas store leaves in their cheek pouches to eat it later. Koalas hug trees to cool off on hot days. Female koalas, when in captivity, can engage in lesbian behaviour. Koalas have human-like fingerprints. Young elephants, pandas, koalas, and hippos eat the feces of their mothers. Australian koalas are in danger of extinction because over half of them have chlamydia. Darwin suggested the appendix may have been used for digesting leaves. This theory is supported by koala and horse appendixes which do just that. A koala's brain is only 0.2% of its body weight. There were over 10 million koalas before British settlers arrived in Australia. Now, there are around 43,000 in the wild. Australia has 10 times more camels than koalas. Koalas, Iguanas, Komodo dragons and most marsupials have a bifurcated penis. Koalas in the wild live from 13 to 18 years. A koala's gestation period lasts 33 to 35 days. Due to their small brains, koalas are unable to perform complex, unfamiliar tasks such as eat leaves off of flat surfaces.