African pygmy squirrel
|African pygmy squirrel|
(Le Conte, 1857)
|Range map of the African pygmy squirrel|
The African pygmy squirrel (Myosciurus pumilio) is a species of rodent in the Sciuridae family. It is monotypic within the genus Myosciurus. It is found in Cameroon, Republic of the Congo, Equatorial Guinea, and Gabon. Its natural habitat is subtropical or tropical moist lowland forests. It is threatened by habitat loss. It is the world's smallest squirrel measuring to about seventy millimeters, about the size of a mouse.
African pygmy squirrels are diurnal and live in trees. These squirrels are found in many forests in Africa. They prefer lower levels of the canopy, and spend most of the time at heights up to five meters.
African pygmy squirrels are the smallest squirrel species in the world. These pygmy squirrels have longer hind limbs than forelimbs, an arched profile skull, rooted cheek teeth, and ever growing incisors. The African pygmy squirrel’s tiny body is more mouse-like than squirrel-like. The borders of the eyes and ears are rounded with white edges at the tip. The coat is light olive white in the under parts and buffy umber brown in the upper parts. The standard adult mass is 16.5 grams. This species has one premolar in each side of the upper jaw. There is slight sexual dimorphism between males and females, with female body size moderately smaller than males but male cranial size is slightly smaller than females. The head and body length is about 60–75 mm and the tail has a measurement of 50–60 mm in length. Other physical features include: endothermy, homeothermy, and bilateral symmetry.
Information regarding the African pygmy squirrel’s reproduction has not been fully defined. Generally arboreal squirrels have a polygamous mating system, where there is male-male competition for access to females. Eventually the female surrenders and mates with the most competitive, and they will mate in a protected area to prevent attacks or threats during copulation. The average number of offspring is about 2. It has been indicated that breeding occurs early during the year. Breeding appears to be concentrated seasonally based on observations of similar squirrel species, but it is not known which season favors breeding. Females provide all the parental care for the offspring, but researchers have not defined the details.
African pygmy squirrels live in trees, they are diurnal squirrels that spend time searching for food, due to their small size. They are the only species of squirrels that travel upside down and right-side up along the branches of trees. African pygmy squirrels are solitary, but they have been observed with other individuals. They do not participate in grouping together to attack predators.
Communication and perception
African Pygmy Squirrels have keen hearing, vision, and smell. They use the vibrissae on their bodies to help them in navigation of tree trunks and branches. A low-intensity alarm vocalization has been recorded and it is described as a “faint pipping sound,” seeming to alert and call attention to nearby danger. These calls may warn young or nearby animals of a threat.
Unlike most squirrels, African pygmy squirrels don’t cache food, meaning they don’t hide and store their food. Myosciurus pumilio species are omnivorous. These squirrels eat scrapings from bark, insects, and fruit. It is theorized that oily spores from microscopic fungus may be the primary substance these squirrels obtain from the bark. African pygmy squirrels are bark gleaners and forage incessantly.
African pygmy squirrels are victims to birds of prey. Also some other known predators are civets, snakes, and army ants. These squirrels have a cryptic color and remain aware to protect themselves from predators.
Deforestation and habitat degradation is the main threat to this species, as it reduces where they live due to low population numbers and its specific ecology. In western Central Africa there is poor environmental governance, illegal logging operation, population growth, and weak protection of the area are some of the threats these squirrels are experiencing. Deforestation is the overall dominant threat to the African pygmy squirrel, which reduces their habitat for this squirrel and countless other species. According to the IUCN, Myosciurus pumilio, once classified as “vulnerable,” has now been listed as “least concern.”
Baillie, J. and Groombridge, B. (compilers and editors) (1996). 1996 IUCN Red List of Threatened Animals. IUCN, Gland, Switzerland.
Grubb, P. 2004. Myosciurus pumilio. In: IUCN 2004. 2004 IUCN Red List of Threatened Species. Downloaded on 14 March 2006.
Emmons L.H. 1980. Ecology and resource partitioning among nine species of African rain forest squirrels. Ecological Monographs 50 (1): 31-54
Emmons L.H. 1979. Observations on litter size and development of some African rainforest squirrels. Biotropica 11 (3): 207-213
Emmons L.H. 1979. A note on the forefoot of Myosciurus pumilio. Journal of Mammalogy 60 (2): 431-432
Gharaibeh B.M. and Jones C. 1996 Myosciurus pumilio. Mammalian Species 523: 1-3: 17
Jones, C., H. Setzer. 1970. Comments on Myosciurus Pumilio. Journal of Mammalogy, 51/4: "813-814.
Macdonald, D. (ed.) 2001. The New Encyclopedia of Mammals. Oxford University Press, Oxford, New York.
Nowak, R.M. (ed.) 1999. Walkers Mammals of the World. Sixth edition. The Johns Hopkins University Press, Baltimore and London.
Schlitter D.A. 1989. African rodents of special concern: A preliminary assessment. In Lidlicker (ed)(1989) Rodents: A world survey of species of conservation concern. Occas. pop. Internatl. Union conservation. Nat Species Survival Comm. No4, iv +60pp.
van Tienhoven A., Hayssen V. and van Tienhoven A. 1993. Asdell's patterns of mammalian reproduction: a compendium of species-specific data: i-viii, 1-1023