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.
Because the rainforests of equatorial Africa were little explored until the 19th century, observations of the scaly-tailed flying squirrels were not made by Europeans until well after the flying squirrels, gliding marsupials and colugos had become known.
Their distinctive features were first recorded in 1843 by George Waterhouse in the Proceedings of the Zoological Society of London. His description of a Lord Derby’s Scaly-tailed Flying Squirrel was made available by the efforts of a Mr Fraser who was a naturalist on an expedition to Niger in central Africa, and had brought back a specimen from Fernando-Po, now Bioko Island. Waterhouse immediately compared the strange species with the flying squirrels with which he was already very familiar:
Upon a cursory inspection this animal would be regarded as a species of Pteromys, having most of the general external characters of the members of the group; there are, however, some points of distinction between the present animal and the large flying squirrels, which are important; of these the most conspicuous are the extraordinary scales which cover the underside of the basal third of the tail: These scales are of a pale horn-colour, sixteen in number in one of the two specimens before me, and fifteen in the other, and arranged in two longitudinal series. ... The lateral flying membrane extends from the wrist to the ankle, and is supported moreover by a long cartilage in front, as in Pteromys; but this cartilage has its origins at the elbow-joint, and not at the wrist, as in the genus just mentioned. The interfemoral membrane extends to the heel, and is moreover attached to the sides of the tail, and when expanded forms almost a straight line.
In 1853, the French palaeontologist and entomologist, François Louis Paul Gervais published a major work on mammals: Histoire naturelle des mammifères: avec l’indication de leurs moeurs et de leur rapports avec les arts, le commerce et l’agriculture. Born in Paris, where he obtained the diplomas of doctor of science and of medicine, Gervais began his palaeontological research as an assistant in the laboratory of comparative anatomy at the Muséum national d’Histoire naturelle. In 1841 he was appointed to the chair of zoology and comparative anatomy at the Faculty of Sciences in Montpellier. His examination of a second species, Anomalurus pelii, from the west coast of Africa, led him to record:
In their external characteristics the anomalures closely resemble the Pteromys, and like them they have wing-like expansions between the limbs, but they also have a membrane between the thighs, and the base of the tail is included in it. The nails of these animals are more curved, and packed together more tightly, than those of the Pteromys. The tail is long, partly free and in the shape of a plume; it looks very strange, with large cornified scales, overlapping one with the other, which cover its base underneath. The fur is soft and supple, however, and there is no sign of spines anywhere on the body; the ears are of normal size and partly bare; the moustaches are very long.
The incisors are smooth on their anterior surface, and the molars, of which there are four pairs, are pretty similar in shape to those of the Cercomys [South American rodents known as Punaré] and certain other animals related to the porcupines; they have clear roots and their crowns, where they have been a little worn down by use, show four oval islands of enamel surrounded by a rather winding outer circle. The teeth decrease slightly in size from the first to the last in each jaw.
The examination that I made of the skull of these strange animals has lead me to believe that they should be brought back into the large family of Hystricidae [Old World porcupines], into which I will provisionally place them, while admitting that there are some characteristics that link them with dormice [Gliridae] and with Theridomys [extinct rodents].
In 1875, Edward Alston gave a similar general description of this group. He also made comparisons with the flying squirrels and noted that:
In external appearance the Anomalures very closely resemble the larger flying squirrels (Pteromys) — their most striking outward distinction being the double series of large salient scales on the lower surface of the first third of the tail, and the fact that the cartilage which serves to extend the flying expansion has its origin at the elbow instead of at the wrist. They are also described as having similar habits, climbing lofty trees, and passing by a great sailing bound from the summit to another stem; in ascending a tree the caudal scales are pressed against the trunk and thus serve as a ‘climbing-iron’.
Biak Glider
Petaurus biacensis
Bartel’s Flying Squirrel
Hylopetes bartelsi
Gray-headed Giant Flying Squirrel
Petaurista caniceps
Smoky Flying Squirrel
Pteromyscus pulverulentus