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Anomalurus beecroftiBeecroft's scaly-tailed squirrel

By Amanda Merkel

Geographic Range

Beecroft's scaly-tailed squirrels inhabit the tropical and subtropical forests of West and Central Africa. (Rosevear, 1969; Feldhamer, et al., 1999)

Habitat

Beecroft's scaly-tailed squirrels prefer the upper canopy levels of virgin tropical and subtropical rainforest. (Rosevear, 1969; Macdonald, 1984; Nowak, 1999; Grzimek, 1990)

  • Range elevation
    35 m above ground (high) m
    ft

Physical Description

Anomalurus beecrofti is squirrel-like in form with soft, thick fur that is sometimes curly with some parts of the pelage having long hairs with dark tips on the dorsal side. This makes the fur look brindled, with the majority of the fur being slate-colored. The coloring of the the ventral side of Anomalurus beecrofti varies. It is often slate-colored with orange tips. The fur can also appear to be a whitish color. On the crown of the head there is a small spot of white hairs. The throat is a greyish color. There is also a pale area at the base of the back of the neck. The ears are smaller and more narrow than Anomalurus derbianus and there is no black on the ears or face. Anomalurus beecrofti has large eyes and long whiskers. The incisors are well-developed and the molars are small with flat crowns. The auditory bullae are more inflated and the cheekteeth are more narrow than Anomalurus derbianus. The digits are well-developed with strong claws. Beecroft's scaly-tailed squrirrels have a gliding membrane that extends between their forelimbs and hindlimbs and between their hindlimbs and tail. The membrane is supported by a rod of cartilage in the front. This cartilage stems from the elbow joint instead of from the wrist, as in true flying squirrels. There are sparse amounts of hair on the underside of the flight membrane and large amounts of hair on the outerside. The tail is short, black and thin-haired with 16 to 18 scales on the underside of the tail near the base. The approximate body length is 25 to 31 cm, the approximate tail length is 19 to 23 cm, and the approximate weight is 0.6 to 0.7 kg. (Grzimek, 1990; Nowak, 1999; Rosevear, 1969)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    600 to 700 g
    21.15 to 24.67 oz
  • Range length
    25 to 31 cm
    9.84 to 12.20 in

Reproduction

There is no information concerning mating systems in Anomalurus beecrofti.

Information about reproduction in Anomalurus beecrofti is scarce. The main breeding season seems to be at the end of the rainy season in West Africa. In general, scaly-tailed squirrels give birth to one young. The gestation period is unknown. Newborns are large and covered with hair. They are able to open their eyes and move around soon after birth. Copulatory plugs have been noted in the vagina of pregnant females. (Rosevear, 1969; Macdonald, 1984; Grzimek, 1990)

  • Breeding interval
    One to two times a year
  • Breeding season
    Breeding occurs during the rainy season of west and central Africa.
  • Average number of offspring
    1

The offspring of Anomalurus beecrofti are hidden in the nest and are fed by both parents until they are almost full grown. They are fed food that is well masticated by the parents. When the parents bring the food to their young, their cheeks are said to be swollen to the size of a tangerine. (Rosevear, 1969)

Lifespan/Longevity

The lifespan of Anomalurus beecrofti is scarcely known in the wild and in captivity. One record of an anomolurid being held in captivity had the animal living in a cage for 14 months with a Dendrohyrax species. It is not known if the specimen died or was released. (Rosevear, 1969)

Behavior

Anomalurus beecrofti are mainly nocturnal and crepuscular. They are primarily arboreal and sleep during the day high up on the outsides of trees in nests made of twigs and leaves, relying on camouflage to hide from predators. This is different than other members of the family Anomaluridae that inhabit hollow trees for rest. They may live alone or in pairs and several squirrels may inhabit the same tree. They leave their nest at dusk and , using their gliding membranes, glide down to lower branches to forage. The scales on their tails are used to stop them during landing, so they do not skid. These scales are also used to help them cling to the rough bark of the trees they climb. They are not very comfortable on the ground and it is said that they only reach the ground by accident or mistake. Their awkwardness on the ground is due to their gliding membrane getting in the way of their legs when trying to walk. They are able to run along tree branches like true flying squirrels. (Rosevear, 1969; Nowak, 1999; Grzimek, 1990)

Communication and Perception

The well-developed auditory bullae and relatively large ears of Beecroft's scaly-tailed squirrels have led researchers to believe that acoustic communication is important to them. The call of Anomalurus beecrofti is described as "something between a whistle and a hoot" by Rosevear (1969). Twittering calls have also been noted to occur at night in these squirrels. In the family, Anomaluridae, hissing sounds have been noted when these animals feel threatened. They also are likely to use vision, touch, and chemical cues in communicating with conspecifics. (Rosevear, 1969; Nowak, 1999; Grzimek, 1990)

Food Habits

Beecroft's scaly-tailed squirrels are herbivorous, feeding mainly on bark, leaves, fruit, seeds, and nuts. Their well-developed jaws are thought to be used to crack the hard shells of nuts and to gnaw at tough outer bark. (Rosevear, 1969; Nowak, 1999; Grzimek, 1990)

  • Plant Foods
  • leaves
  • roots and tubers
  • wood, bark, or stems
  • seeds, grains, and nuts
  • fruit

Predation

There is no information available on predators of Beecroft's scaly-tailed squirrels. They are not hunted by natives because of their small size. They may be preyed on by large raptors, arboreal snakes, and cats. The brindled color pattern on the dorsal side of Anomalurus beecrofti serves as camouflage when they are clinging to trees. (Rosevear, 1969; Grzimek, 1990)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Information about the role that Anomalurus beecrofti plays in the ecosystem is scarce, although they do feed on fruits and seeds and may act as a seed disperser. (Grzimek, 1990)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

Information about how Anomalurus beecrofti can benefit humans is scarce.

Economic Importance for Humans: Negative

There are no known adverse affects of Anomalurus beecrofti on humans.

Conservation Status

Anomalurus beecrofti is listed as a CITES Appendix III species. This is primarily due to habitat loss because of deforestation in West and Central Africa. (Grzimek, 1990; "Convention on International Trade in Endangered Species of Wild Fauna and Flora", 2001)

Other Comments

The systematic position of Anomalurus beecrofti and the entire Anomaluridae family within the order Rodentia has been greatly debated. Despite their common name, they are not squirrels (family Sciuridae) and may not be closely related. (Rosevear, 1969)

Contributors

Amanda Merkel (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor), University of Wisconsin-Stevens Point.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

crepuscular

active at dawn and dusk

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

frugivore

an animal that mainly eats fruit

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

male parental care

parental care is carried out by males

motile

having the capacity to move from one place to another.

nocturnal

active during the night

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

CITES Secretariat--International Environment House. 2001. "Convention on International Trade in Endangered Species of Wild Fauna and Flora" (On-line ). Accessed 12/1/02 at http://www.cites.org/.

Feldhamer, G., L. Drickamer, S. Vessey, J. Merritt. 1999. Mammalogy: Adaptation, Diversity, and Ecology. McGraw-Hill Higher Education.

Grzimek, B. 1990. Grzimek's Encyclopedia of Mammals. New York: McGraw-Hill, Inc.

Macdonald, D. 1984. The Encyclopedia of Mammals. New York, New York: Facts on File, Inc..

Nowak, R. 1999. Walker's Mammals of the World. Baltimore, Maryland: The John Hopkins University Press.

Rosevear, D. 1969. The Rodents of West Africa. Great Britian: The Thanet Press.

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