Koala (Phascolarctos cinereus, or incorrect koala bear [a]) is a arboreal herbivore marsupials native to Australia. It is the only extant representative of phascolarctidae, and its closest relative is the wombat. Koala is distributed in the coastal areas of the eastern and southern parts of the mainland, inhabiting Queensland, New South Wales, Victoria and South Australia. Its thick, tailless body and big head, round ears and big spoon shaped nose are easy to recognize. Koala is 60-85 cm (24-33 inches) long and weighs 4-15 kg (9-33 pounds). The color of sebum ranges from silver grey to chocolate brown. The koalas of the northern population are usually smaller and lighter in color than those of the southern population. These populations may be different subspecies, but this is controversial.

Koalas usually live in open Eucalyptus woodlands, where the leaves make up most of their diet. Because of the limited nutrition and calories in this Eucalyptus diet, koala is largely sedentary, sleeping up to 20 hours a day. They are social animals and are only connected between the mother and the dependent offspring. Adult men communicate with yellers, which scares rival rival rival and attracts partners. The presence of the male was marked by the secretion of its chest odor gland. As a marsupial, the koala gave birth to an immature young man who crawled into his mother's pouch and lived there for the first six to seven months. These young koalas, known as Joey, were completely weaned around the age of one. Koala has few natural enemies and parasites, but it is threatened by various pathogens such as Chlamydia bacteria and koala retrovirus, as well as forest fires and droughts.

Koala was hunted by Aboriginal Australians and depicted for thousands of years in mythology and cave art. In 1798, the first recorded encounter between Europeans and koalas was recorded, and the naturalist George Perry published an image of the animal in 1810. Botanist Robert Brown first gave a detailed scientific description of koala in 1814, although his work has not been published for 180 years. Pop artist John Gould exemplified the koala and introduced it to the general public in the UK. In the 19th century, several British scientists revealed more details about animal biology. Because of its unique appearance, koala is recognized as the symbol of Australia all over the world. The International Union for conservation of Nature lists koala as "vulnerable". The Australian government also lists certain populations in Queensland and New South Wales as vulnerable groups. [4] The animal's fur was hunted in large numbers in the early 20th century. The mass culling in Queensland caused a strong public protest and a movement to protect the species. Shelters have been established and migration has been moved to new areas of Koala where habitats have become fragmented or reduced. The biggest threat to their survival is habitat destruction caused by agriculture and urbanization.