Mammals
Feathertail Glider
Acrobates pygmaeus · also called feathertail glider, pygmy gliding possum
The feathertail glider is the smallest gliding mammal in the world — a marsupial the size and weight of a house mouse that launches from the canopy and sails as far as 28 metres to the next tree, steering the whole way with a stiff, flat tail that looks exactly like a bird’s feather. It can also run straight up a window.
Overview
Feathertail gliders live in the eucalypt forests of eastern Australia. Head and body measure only 6.5–8 cm, with a tail about as long again, and the animal weighs just 10–14 g. It feeds on nectar, pollen, honeydew, and small insects, and pollinates banksias and eucalypts as it goes.
The feather tail
The tail is flattened and stiffened, with two rows of long fringing hairs down the sides, so it looks like a feather. The glider uses it as a rudder and airbrake, twisting it to steer in the air and flaring it to slow the landing. The gliding membrane itself is small, running only from elbow to knee — but enough for a 14-gram animal.
Feet that grip glass
The toe pads carry fine ridges kept moist by sweat glands, generating strong wet adhesion. The glider can run up smooth vertical glass and hang upside down beneath a leaf.
Status
The feathertail glider is Least Concern, common in suitable forest, though it depends on tree hollows and year-round flowering plants. What was thought to be one species was split into two in 2021. On cold nights it drops into torpor, often huddled with dozens of others in a single tree hollow.
Feathertail Glider: common questions
How can something so small glide so far?
A feathertail glider weighs only about 12 grams, and at that size air resistance is proportionally large, which actually helps a glider. Even its modest elbow-to-knee membrane and its fringed tail present enough surface area, relative to its tiny mass, to slow its fall dramatically and convert much of it into forward travel. Launched from high in a tree it can cover 20 to 28 metres, losing height gradually, while using its tail and limbs to bank, correct its path, and line up a landing on a target trunk. Being light also means a hard landing does no harm.
Why is its tail shaped like a feather?
The tail is flattened top to bottom and stiffened, and it carries a row of long, stiff hairs projecting sideways from each edge, spaced out like the barbs of a feather. This gives the tail a broad, flat blade with very little weight. In the air the glider holds the tail out behind and twists and tilts it to steer, and flares it just before landing to act as an airbrake, so a large, light, controllable rudder is exactly what a small glider needs, and a feather-like structure is an efficient way to build one.
Can a feathertail glider really climb glass?
Yes. The pads under its toes are covered in tiny curved ridges, and small sweat glands keep them slightly damp. The thin film of moisture, combined with the ridged surface, produces strong adhesion through surface tension and friction, the same wet-grip principle that lets a tree frog stick to a leaf. It is enough for the glider to run straight up a smooth vertical pane of glass or a polished trunk and to hang upside down beneath a leaf, and it lets the animal exploit smooth-barked eucalypts that many other small mammals cannot climb.
Is the feathertail glider related to the sugar glider or to flying squirrels?
It is a marsupial and a close relative of the sugar glider and the other gliding possums of Australia and New Guinea, all of which evolved gliding within the marsupial group. It is not related to the flying squirrels of the Northern Hemisphere, which are placental mammals that arrived at the same solution independently, nor to the gliding colugos of Southeast Asia. The feathertail glider is simply the smallest member of the marsupial gliding radiation, and its feather tail is a feature unique to it rather than shared with the larger gliders.