Species: Phascolarctos cinereus
Basic koala facts:
The koala, an iconic Australian symbol, is often called the "koala bear," but it is actually a marsupial, not a bear. Marsupials are a sub-type of mammals whose distinguishing characteristic is that females give birth to relatively undeveloped young that then live in pouches that contain mammary glands, where their young live until they are old enough to emerge.
Koalas are largely nocturnal.
Koalas are solitary animals that typically have a certain territory. Males mark this with a scent gland that they rub against trees
A full-grown adult male weighs around 30 pounds (12.5 kilograms) and about 2.6 feet (81 centimeters) in length, while a female weighs up to 22 pounds (10 kg) and grows to 2.4 feet (73 cm). Koalas vary in size regionally though: Those from the northern parts of the animal's range are much smaller and have gray fur, while those from southern Australia have longer fur that is a browner color due to the colder climate in which it dwells.
Koalas live in trees and eat primarily eucalyptus leaves. These leaves are very fibrous, low in nutrition, and contain a toxin that must be filtered out by the animal's digestive system. Their strong jaws also help koalas chew their tough food.
Koalas have an excellent sense of smell that can differentiate between different types of eucalyptus leaves and signal the amount of toxin in the leaves.
Koalas also have excellent hearing, though poor eyesight, so they have to recognize predators by sound, according to the Australia Zoo.
Koalas have strong limbs and long, sharp claws that help them climb tree trucks.
Koalas' have five fingers, one of which is an opposable thumb, which helps them grip tree branches. Their thickly padded tail helps them sit for hours in trees.
Though koalas generally don't make noise, the male has a loud call during breeding season that can be heard about a kilometer away. Koalas can make other sounds from snores to screams.
Female koalas give birth after about 35 days of gestation.
Baby koalas are called joeys. They are only about 2 cm long when they are born and are blind and furless.
When born, the joey climbs into its mother's pouch and remains there protected and nursing for about six months. A sphincter muscle keeps the joey from falling out, according to the Adelaide Zoo.
When it emerges from the pouch, the joey remains with its mother for six more months, riding on her back, feeding on both milk and eucalyptus leaves. The koala is usually weaned by the time it is a year old.
The average lifespan of a koala in the wild is between 10 to 14 years.
Where koalas live:
Koalas are found in the eastern half of Australia, in the states of Queensland, New South Wales, Victoria and South Australia, as well as several small islands. The fragmentation of habitat and population numbers differ from state to state.
Conservation status: Least Concern
There are far fewer koalas in Australia today than there were when European settlers first arrived. In the early 20th century, they were hunted to near extinction for their fur, according to the Adelaide Zoo.
Though they are subject to threats, particularly habitat encroachment and fragmentation, as well as disease, fire, drought and road deaths, the koala is considered a species of least concern by the IUCN because of its comparatively large population and wide distribution. The rate of decline is different between different koala populations.
Many koalas live on private property, which makes establishing protection difficult.
In April 2012, the Australian government listed koalas as a threatened species, facing threats from both urban expansion and climate change.
The word "koala" derives from an ancient Aboriginal word meaning "no drink" since they rarely ever drink water because they get 90 percent of their hydration from gum leaves.
Because of their low metabolism and the effort it takes to digest their food, koalas remain motionless 16 to 18 hours a day and spend most of that time sleeping, according to the Adelaide Zoo.
Like humans, koalas have fingerprints. They are the only other mammals besides primates to have them.
Koala fur is waterproof. It also protects them from both high and low extreme temperatures.
Though there are more than 700 species of eucalyptus in Australia, koalas eat only 50 of them.
Other koala resources:
National Koala Conservation and Management Strategy – Government of Australia