The koala (Phascolarctos cinereus or, inaccurately, koala bear[a]) is
an arboreal herbivorous marsupial native to Australia. It is the only
extant representative of the family Phascolarctidae, and its closest
living relatives are the wombats. The koala is found in coastal
areas of the mainland's eastern and southern regions, inhabiting
Queensland, New South Wales, Victoria and South Australia. It is
easily recognisable by its stout, tailless body; round, fluffy ears;
and large, spoon-shaped nose. The koala has a body length of 60–85
cm (24–33 in) and weighs 4–15 kg (9–33 lb). Pelage colour ranges
from silver grey to chocolate brown. Koalas from the northern
populations are typically smaller and lighter in colour than their
counterparts further south. It is possible that these populations are
separate subspecies, but this is disputed.
Koalas typically inhabit open eucalypt woodlands, and the leaves of
these trees make up most of their diet. Because this eucalypt diet has
limited nutritional and caloric content, koalas are largely sedentary
and sleep for up to 20 hours a day. They are asocial animals, and
bonding exists only between mothers and dependent offspring. Adult
males communicate with loud bellows that intimidate rivals and attract
mates. Males mark their presence with secretions from scent glands
located on their chests. Being marsupials, koalas give birth to
underdeveloped young that crawl into their mothers' pouches, where
they stay for the first six to seven months of their life. These young
koalas are known as joeys, and are fully weaned at around a year.
Koalas have few natural predators and parasites but are threatened by
various pathogens, like Chlamydiaceae bacteria and the koala
retrovirus, as well as by bushfires and droughts.
Koalas were hunted by indigenous Australians and depicted in myths and
cave art for millennia. The first recorded encounter between a
European and a koala was in 1798, and an image of the animal was
published in 1810 by naturalist George Perry. Botanist Robert Brown
wrote the first detailed scientific description of the koala in 1814,
although his work remained unpublished for 180 years. Popular artist
John Gould illustrated and described the koala, introducing the
species to the general British public. Further details about the
animal's biology were revealed in the 19th century by several English
scientists. Because of its distinctive appearance, the koala is
recognised worldwide as a symbol of Australia. Koalas are listed as of
Least Concern by the International Union for Conservation of Nature.
The Australian government lists populations in Queensland and New
South Wales as Vulnerable. The animal was hunted heavily in the early
20th century for its fur, and large-scale cullings in Queensland
resulted in a public outcry that initiated a movement to protect the
species. Sanctuaries were established, and translocation efforts moved
to new regions koalas whose habitat had become fragmented or reduced.
The biggest threat to their existence is habitat destruction caused by
agriculture and urbanisation.