Pygmy scaly-tailed flying squirrel  (Idiurus zenkeri)

Classified as Least Concern (LC) on the IUCN Red List (1).

The pygmy scaly-tailed flying squirrel is the smallest of seven species of mainly gliding rodents belonging to the family Anomaluridae (4) (5). In common with all but one member of the family, the pygmy scaly-tailed flying squirrel has a membrane that extends along the sides of its body from limb to limb (3) (6) (7). Stretched out in flight, the membrane forms a square parachute, enabling these arboreal rodents to glide incredible distances from one tree to another (5) (7). This adaptation to life in the trees is akin to the flying membranes displayed by Australian flying possums and true flying squirrels but is actually the product of convergent evolution rather than close ancestry (3) (7). It has a fine silky coat, predominately tawny coloured but slightly paler along the neck and belly (3) (6). A small portion of the underside of its long, thin tail is covered with a roughened file-like surface that possibly aids in climbing the rough bark of trees (3) (6) (7). The upperpart of the tail is sparsely covered with long hairs (3) (6).

The distribution of the pygmy scaly-tailed flying squirrel extends from southern Cameroon and Equatorial Guinea in the west, to the Democratic Republic of Congo and western Uganda in the east (3) (4) (8).

Dependant on mature trees for food and shelter, this rodent only occurs in dense tropical forests (3) (6).

As an inhabitant of a remote and poorly studied region of the world, very little is known about the ecology of the pygmy scaly-tailed flying squirrel, other than largely anecdotal accounts from chance encounters (3). It is certainly inactive during the day, passing the sunlit hours sheltering in hollow trunks and branches as much as 40 metres above the ground and in colonies of up to 100 individuals (3) (6). In contrast, during the night it is extremely energetic and may travel several kilometres to feed, climbing to the tops of trees, leaping off and gliding down to the trunk of another tree which in turn is ascended. With an impressively slow-rate of descent it is reportedly able to travel more than a 100 metres in a single glide (3) (5) (6) (7). Considered to be primarily herbivorous, the pulp of oil palm fruits is thought to be its main food source but it may also occasionally consume insects and possibly nectar (5) (6).

Other than reports of female pygmy scaly-tailed flying squirrels leaving the colony to bear a single young, nothing is known about its reproductive biology (7). In other Anomalures, the female has two litters of one to three young per year, which at birth are active, have a full body of fur and open eyes (6) (7).

In the absence of a significant ecological study of the pygmy scaly-tailed flying squirrel, it is difficult for conservationists to properly assess how threatened it is. Nonetheless, of most concern at this stage, particularly given the dependence of these rodents on mature forests, is the effect of logging activities within its range (3) (6). Between 1990 and 2000, commercial harvesting of timber, together with land clearance for agriculture, accounted for a loss of 9.1 million hectares of land in central Africa (9). Fortunately, it is thought that the wide distribution of the pygmy scaly-tailed flying squirrel means that deforestation is probably only a threat to the species in localised parts of its range, and that there is currently no significant threat to the species as a whole (1).

There are currently no strategies in place for the conservation of the pygmy scaly-tailed flying squirrel, or indeed for any Anomalure. However, despite commercial conflicts of interest, positive efforts are being made to protect central African forests from further degradation and loss of biodiversity. This includes the signing in 2005 by ten central African nations of the first region wide conservation treaty to protect seven percent of Congo Basin forests (10).

View information on this species at the UNEP World Conservation Monitoring Centre.

For further information on forest conservation in central Africa see:

• WWF:
  www.worldwildlife.org