Most people know the adorable, fuzzy-eared creatures that live in Australia’s eucalyptus forests as koala bears — however, that name is only half correct. Koalas are as much a bear as humans are: we're all classified as Mammalia, at least! That’s about it. So, if they’re not bears, how did we start calling koalas that?

Koala history

Up close view of koala hugging tree branch in the wild
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Koalas have inhabited the continent of Australia for a long time, well before the arrival of any humans. According to fossil evidence, koala-like animals have lived in Australia for over 25 million years (humans only arrived about 60,000 years ago). At the time, koalas and humans lived in harmony. Koalas were actually an important resource for Aboriginal Australians for food and clothing. Their name likely comes from Darug, an Aboriginal dialect that the earliest European explorers in the 18th century would have heard. While it's often theorized that koala means "no drink," a reference to how koalas get most of their water intake from the eucalyptus they eat rather than traditional water sources, it's likely that the name simply derives from from the Darug word for the region the cuddly marsupials were found in.

Europeans arrive

Koala parent and cub resting on a thin tree branch with blurry trees in background
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The first Europeans arrived in Australia in 1788. A decade later, during a trip into the Blue Mountains near modern-day Sydney, John Price, a servant of New South Wales' Governor John Hunter, saw some koalas and described them in his notes (Price was also the first to note the existence of wombats). Since he was not a scientist, Price described them in the best way that he could with what knowledge he had. They resembled a small bear, so that’s what he called them.

Based off Price’s account, in 1816, koalas were given the scientific name Phascolarctos cinereus, which means “ash grey pouched bear.” It wasn’t until later that researchers realized that koalas aren’t actually bears at all! It was a classic case of “ready, fire, aim.”

Koalas are marsupials

Several wild kangaroos stand in an open field on a clear day
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While koalas and bears are both classified as mammals, that’s where their similarities end. Koalas are marsupials. That means they give birth to their young prematurely and continue developing the newborn in their pouch until it’s old enough to survive in the outside world. Even then, young koalas stay with their mothers, literally hanging off her back or belly, until they’re about a year old. Australia is home to about 250 species of marsupials, including kangaroos, wombats, and wallabies.

Though they bear resemblances to bears, koalas are more closely related to kangaroos and opossums.

Koala facts

Wild koala clambers across thin tree branch under forest canopy
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Koalas are mostly found in the eucalyptus forests of eastern Australia, where they spend most of their lives in the trees. To help them climb, Koalas have six opposable “thumbs” – two on each front “hand” and one on each foot – to help them grasp branches. They eat mostly the leaves from eucalyptus trees. A full-grown koala can eat up to 10 percent of its body weight in leaves!

When they’re not eating, they’re probably asleep. A koala’s favorite hobby is napping. Koalas sleep around 18-22 hours per day, which is mostly due to the lack of nutrition in eucalyptus leaves. Eucalyptus leaves have almost no nutritional value, leaving koalas with little energy to stay active for long periods of time.

Declining population

Young koala sleeps comfortably on a curved tree branch
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Koalas were plentiful in Australia until the early 20th century. In the 1920s and '30s, they were widely hunted for their soft pelts. Millions of koalas were killed and they became extinct in several regions of the continent. Hunting was eventually banned to help the population recover.

Although they have very few natural predators, koala numbers are continuing to decline due to deforestation. Koalas need about 100 trees per animal to survive, and the loss of habitat due to deforestation and brush- and wildfires have left koalas more in danger than ever.