Logo: Gliding mammals of the world

Gliding Mammals of the World

The world’s gliding mammals are an extraordinary group of animals that have the ability to glide from tree to tree with seemingly effortless grace. There are more than 60 species of gliding mammals including the flying squirrels from Europe and North America, the scaly-tailed flying squirrels from central Africa and the gliding possums of Australia and New Guinea.

Flying Squirrels: Origins

There has been much debate on the origins and relationships of the flying squirrels. Did they evolve from ancestral tree squirrels or did they evolve independently during the Eocene (56–34 mya) from another group of rodents known as the paramyids? The hypothesis that flying squirrels are not derived from tree squirrels is based on the observation that they were as diverse in the Miocene (23–5 mya) as they are at present, and the supposition is that this diversification required a long period of evolution after the flying squirrels diverged from the tree squirrel lineages. Despite this, recent molecular studies strongly support the theory that flying squirrels evolved from one particular group of tree squirrels, the Sciurini, long after the Family Sciuridae evolved from the paramyids.

A second issue has been whether gliding evolved twice within tree squirrels from both South-East Asian tree squirrels (Callosciurini) and from Holarctic tree squirrels (Sciurini), or whether flying squirrels are derived from a single ancestor. An apparent high diversity of fossil flying squirrel teeth early in squirrel history has been taken as evidence that flying squirrels have an origin independent of tree and ground squirrels, justifying the division of the squirrel family into two distinct groups and even promoting suggestions that flying squirrels belong in a separate family. Morphological and molecular evidence, however, has found that flying squirrels are derived from tree squirrels and are now recognised as a tribe, Pteromyini, within the Family Sciuridae. Molecular studies indicate the divergence of the five major groups of squirrels, including the flying squirrels, took place during the late Eocene and Oligocene (34–23 mya).

A third uncertainty is the grouping of the different genera of living flying squirrels and their affinities with the genera of fossil squirrels that are thought to have been able to glide. At present, none of the fossil genera can categorically be allocated as gliders because at least some of the features used to describe them are also found in at least some tree squirrels. It will not be until the discovery of further fossil remains with adequate postcranial material, such as the limbs that are long and thinner in gliding mammals, that the ability of the fossil attributed to gliders can be confirmed.

Flying squirrels of the genus Hylopetes
Flying squirrels of the genus Hylopetes (such as this Red-cheeked Flying Squirrel) are closely related to the dwarf flying squirrels, Petinomys. They are thought to have diverged from each other about 2.2 mya.
Random species

Northern Glider / Petaurus abidi

Northern Glider
Petaurus abidi

Hose’s Pygmy Flying Squirrel / Petaurillus hosei

Hose’s Pygmy Flying Squirrel
Petaurillus hosei

Hodgson’s Giant Flying Squirrel / Petaurista magnificus

Hodgson’s Giant Flying Squirrel
Petaurista magnificus

Siberian Flying Squirrel / Pteromys volans

Siberian Flying Squirrel
Pteromys volans

Gliding Mammals of the World provides, for the first time, a synthesis of all that is known about the biology of these intriguing mammals. It includes a brief description of each species, together with a distribution map and a beautiful full-color painting.

An introduction outlines the origins and biogeography of each group of gliding mammals and examines the incredible adaptations that allow them to launch themselves and glide from tree to tree.