Koala “bears” aren’t a type of bear at all, and their non-scientific name doesn’t include “bears” on the end, as is commonly spoken outside of Australia by the English speaking world. They are simply “Koalas”.
So if they aren’t a member of the family Ursidae (bears), what are they? In fact, they are marsupials, along with kangaroos, wallabies, wombats, and possums, among others. Marsupials have the distinctive feature of a pouch, called a “marsupium”. Unlike most marsupials though, a female Koala’s pouch opens downward, rather than upward.
The name “Koala Bear” is thought to come from English speaking settlers around the 18th century, who frequently would name new animals they saw based on what animal it looked like that they were familiar with. Around this same time, Koalas were also often referred to as “tree-bear”, “sloth”, “monkey-bear”, and other such names by these same settlers.
While Koala’s may look cuddly, they are anything but. Their fur is not soft and fluffy like it appears, but rather has more of the consistency of wool. So snuggling with a Koala would feel about like snuggling with sheep, only Koalas have long claws and incredibly strong grips. They also are very solitary animals, preferring to be by themselves most of the time, so make poor pets.
Another myth surrounding Koalas is that they sleep most of the day because they are intoxicated by the eucalyptus leaves they eat. In fact, they simply have very slow metabolisms and it takes a long time for their bodies to process these leaves, which are normally poisonous to most animals. Also, given that they almost exclusively eat eucalyptus leaves, this tends to introduce very little caloric and nutritional value into their diet. So, they have to sleep nearly 20 hours a day, conserving energy and allowing time for their bodies and the microbes in their digestive tract to process the eucalyptus leaves.
Koalas are the only surviving member of the family Phascolarctidae, with all the other types of animals in that family having become extinct.
Phascolarctos comes from the Greek word for “pouch”.
Koalas almost never need to drink water, getting sufficient water from the leaves they eat. In times of drought or when food is scarce, they will drink water from streams and the like, if necessary. But generally speaking, they don’t need to. This is a good thing too, because Koalas are slow moving and easy prey when on the ground.
Eucalyptus leaves are poisonous to most animals, but Koalas are uniquely adapted to be able to process the leaves. They have special kinds of teeth that help grind the leaves into a fine paste and then they have a special blend of bacteria in their digest tract that break down the poisonous oils in the leaves so as not to harm the Koalas. These same microbes also are responsible for most of the nutritional value the Koalas get from the leaves, with the microbes breaking down the leaves and producing the various vitamins that the Koala needs to live.
The special blend of microbes found in the stomachs and intestines of the Koala get there through the mother, who excretes a special type of feces, called “pap”, that the baby Koalas eat when they are about ready to leave the pouch. Without these microbes, the Koala would not survive.
When Koalas are first born, they are about the size of a large raisin. At this point, they are also blind and deaf. The extent of their abilities at this stage is simply to climb, which they will do until they reach the mother’s pouch. Once there, they’ll attach to one of the nipples and stay there for the next 6 months or so, until they grow too big to fit in the pouch. The baby Koala, called a “joey” will stay with the mother until it reaches around a year to two years old. The Koala will leave to find its own home once the mother is ready to have another joey.
Despite the fact that Koalas are slow moving animals, they have no real natural predators, due to the fact that they spend the vast majority of their lives high up in trees.
Numbering in the tens of millions only a century ago, today there are only about 40,000-80,000 Koalas alive in the wild, with that number dwindling fast as their natural habitat is destroyed by wildfires and humans.