The quokka, the only member of the genus Setonix, is a small macropod about the size of a domestic cat. Like other marsupials in the macropod family (such as kangaroos and wallabies), the quokka is herbivorous and mainly nocturnal.
Quokkas are found on some smaller islands off the coast of Western Australia, particularly Rottnest Island, just off Perth, and also Bald Island near Albany, and in isolated, scattered populations in forest and coastal heath between Perth and Albany.
The quokka weighs 2.5 to 5.0 kg (5.5 to 11.0 lb) and is 40 to 54 cm (16 to 21 in) long with a 25-to-30 cm-long (9.8-to-11.8 in) tail, which is quite short for a macropod.
It has a stocky build, well developed hind legs, rounded ears, and a short, broad head. Its musculoskeletal system was originally adapted for terrestrial bipedal saltation, but over its evolution, its system has been built for arboreal locomotion. Although looking rather like a very small kangaroo, it can climb small trees and shrubs up to 1.5 metres (4 ft 11 in).
Its coarse fur is a grizzled brown colour, fading to buff underneath. The quokka is known to live for an average of 10 years.
Quokkas have a promiscuous mating system. After a month of gestation, females give birth to a single baby called a joey.
Females can give birth twice a year and produce about 17 joeys during their lifespan. The joey lives in its mother's pouch for six months.
Once it leaves the pouch, the joey relies on its mother for milk for two more months and is fully weaned around 8 months after birth. Females sexually mature after roughly 18 months.
According to en.wikipedia