Scaly-Tailed Squirrels: Anomaluridae

Physical characteristics: Although Lord Derby's anomalure's appearance varies across its range, this species is generally grey to a rich reddish brown with silver throughout. All of the 16 subspecies share the same facial pattern, however, of white cheeks, forehead, and snout with a black band over the nose, around the eyes, and on the back of the head. The fur on their heads is dense and soft, and the silky fur on their bodies can be up to 1 inch (25 millimeters) long. They also all have six pairs of scales underneath their tails. Their tails are shorter than their bodies, the last half being black. Lord Derby's anomalure has furless, pink ears.

Geographic range: This species is widely distributed in an area across central Africa, from Sierra Leone in the west to Kenya in the Lord Derby's anomalures supplement their diet of tree bark with insects, tree sap, nuts, fruits, and flowers. (Illustration by Barbara Duperron. Reproduced by permission.) east, and, less commonly, from Angola in the north to Mozambique in the south.

Habitat: This anomalure favors habitat in moist rainforests and seasonally dry woodlands from sea level to 7,875 feet (2,400 meters), although they are particularly attracted to areas that contain their favorite food trees. With regard to shelter, any tree will do for roosting as long as it is hollow in places. Roosting holes have been observed at both the tops and bottoms of trees, with entryways just large enough for anomalures to fit through. The dens are constructed so that temperature and humidity remain fairly consistent.

Diet: Like most of the larger anomalurids, Lord Derby's anomalure eats the bark of such trees as the miombo, velvet tamarind, ironwood, owala oil, and awoura, preferring the thickest portions of the main truck and large branches. The animals forage among several different trees, taking a thin strip from a tree one night and returning to take another strip during the next night's feeding, stopping when the removal site reaches about 6 inches (15 centimeters) wide to prevent permanent damage to the tree. Lord Derby's usually start a feeding site at natural wounds in a tree's bark caused by growth splits, elephant damage, or falling branches. Interestingly, the trees and this species have evolved together for so long that unlike most other trees, the rodents' food tree species can grow replacement bark. The anomalures supplement their nutrient-poor bark diet with insects, tree sap, nuts, fruits, and flowers.

Behavior and reproduction: Although biologists have yet to study the social aspects of Lord Derby's anomalure behavior, they do know that the animals tend to share dens, and may crowd up to eight individuals into one roosting hole. They are mainly active at night, but seem to enjoy lying in the sun in the early morning and late afternoon. Using their gliding membrane to move across longer distances, they perform a final abrupt upturn to cause their flight to stall and allowing them to land safely. Biologists have measured the glide distances of Lord Derby's anomalure females at 1,770 feet (540 meters), but most are under 328 feet (100 meters). Males typically achieve even greater gliding distances and move through more territory. The Lord Derby's are fairly quiet animals, with vocalizations that include a variety of twitters and purrs along with growling and hissing when threatened or disturbed.

For Lord Derby's anomalures living in the rain forest, breeding occurs year round. For residents of the dry forests, breeding occurs seasonally. Pregnant females often move to a special nursery den, where they give birth to an unknown number of pups. Although the young are large, well formed, and able to move in a coordinated fashion soon after birth, they stay with the female parent until they are almost fully mature. After weaning, they receive chewed-up food from both parents. Observers have noted that mothers and pups will often glide among trees and chase each other playfully.

Lord Derby's anomalures and people: Although biologists have long sought to learn more about this secretive and easily frightened species, there are no records of any significant interactions between Lord Derby's anomalure and humans.

Conservation status: Despite their specialized diet and habitat requirements, Lord Derby's anomalure is not threatened. However, in Ghana, their population is on a conservation watch list due to habitat destruction and degradation. ∎