The feathertail glider (Acrobates pygmaeus) is an Australian marsupial, and is the smallest gliding mammal in the world. They are about 80 millimeters long and weigh only about 12 grams. Despite this small size, they can glide along distances up to 25 meters, from treetop to treetop.

Feathetail gliders are grey-brown in colour with dark eye patches and light patches on the underside of the ears. They are most famous for their long, featherlike tails. It is a very thin, moderately prehensile tail with two rows of long, stiff hairs on either side, giving it its 'feathery' appearance.

As a glider, they have thin, transparent membranes of skin between the forelegs and the hind legs. The membrane is thicker in proportion to other gliders' but smaller in size.

Feathertail gliders are arboreal, and exist on a diet of nectar, pollen, insects and sap. They are group animals, and live in ball-shaped nests containing up to 16 individual animals. However, the usual number is around four.

Feathertail gliders reach sexual maturity at about six months. The females produce up to two litters of 2-3 young a year. Feathertail gliders are marsupials, so the young stay in their mother's pouch for roughly sixty days, then stay with their mother for a further seven months.

Because of their mouselike size, feathertail gliders are vulnerable to several predators, such as foxes, feral cats, snakes, lizards and quolls. Though nocturnal, feathertail gliders are rarely active on clear nights due to the danger of running into these predators.

Feathertail gliders featured on the Australian one-cent coin until 1991, when the one- and two-cent coins were withdrawn from circulation.