Geographic Range
Idiurus zenkeri
is found throughout Upper Cameroon to Rio Muni and Northwest Gabon. The range extends
from the northeast and east portion of Zaire, east of the Lualaga to Lake Kivu, eastern
Nigeria, the Gold Coast, Gabon, Liberia, and west Uganda.
Pygmy scaly-tailed flying squirrels are found in the following countries: Cameroon,
Central African Republic, Congo, the Democratic Republic of the Equatorial Guinea,
and Uganda.
Habitat
Pygmy scaly-tailed flying squirrels are found in moist tropical and subtropical climates.
They are arboreal, occurring mainly in forests composed of the following tree taxa:
Klainedoxa
species,
Pseudoprosopis
species,
Paramacrolobium
species,
Gilbertiodendron
species, and
Pentaclethra
species.
- Habitat Regions
- tropical
- terrestrial
- Terrestrial Biomes
- forest
- rainforest
Physical Description
Pygmy scaly-tailed flying squirrels have a body length from 63 to 75 mm, tail length
of 83 to 104 mm, hind foot length of 14 to 17 mm, ear length of 11 to 15 mm, and greatest
length of skull of 22 mm. They are the smallest of the
scaly-tailed squirrels
. They have a feathery tail. Dorsal fur color is grey to brown and ventral fur color
is whitish. A gliding membrane is located between the fore and hind limbs.
Scaly-tailed squirrels
have silky fur, long whiskers, and two rows of pine cone like scales on the underside
of their tails.
The top of the tail is covered with sparse, 2 cm long hairs. The tail has a row of
short (2 to 3 mm), stiff hairs along both sides. The entire underside of the tail
is hairless, with a 1.5 to 2.5 cm long rough, scaly patch that extends from the tail
base. These scales typically act as anti-skid devices that also provide extra grip
while climbing or support when resting. Sharp claws also provide extra grip.
The fur is fine, although less dense on the gliding membrane. The elbow has a cartilaginous
extension that allows for greater freedom of movement in the upper limbs.
- Other Physical Features
- endothermic
- homoiothermic
- bilateral symmetry
- Sexual Dimorphism
- sexes alike
Reproduction
The mating system of
Idiurus zenkeri
is not reported.
There is little information on reproduction in
Idiurus zenkeri
. It is believed to be similar to
Idiurus macrotis
and other
anomalurids
. Young are precocial and born in litters of up to three young. Parents will finely
chew food in their cheeks and then pass it on to their young during the weaning process.
No pregnant females have been observed. It is thought that females may give birth
to their young away from the colony.
- Key Reproductive Features
- iteroparous
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- viviparous
Like all mammals, females I. zenkeri nurse and care for their young until they are weaned. Otherwise, little is known about the investment of male and female parents and length of dependence.
- Parental Investment
-
pre-fertilization
- provisioning
-
protecting
- female
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
provisioning
Lifespan/Longevity
There is no information known about the longevity of I. zenkeri .
Behavior
Pygmy scaly-tailed flying squirrels are nocturnal, gregarious species that rest in
tree hollows or behind peeling bark with other flying squirrels in groups of up to
100 individuals consisting of both sexes and all ages. They climb with agility on
smooth tree trunks and jump or glide between tree branches. They can glide up to 3
meters between trees without losing height.
Home Range
Home range size of
I. zenkeri
is not reported.
Communication and Perception
Pygmy scaly-tailed flying squirrels emit a mouse-like squeak that is heard when individuals
are disturbed. Communication by scent is important in
anomularids
. Large groin glands produce strong smelling secretions.
Pygmy scaly-tailed flying squirrels have large, forward facing eyes that provide excellent binocular vision and relatively large ears that support acute hearing that could include ultrasonic frequencies.
- Perception Channels
- visual
- tactile
- ultrasound
- chemical
Food Habits
Pygmy scaly-tailed flying squirrels are capable of traveling several kilometers in
search of food. Foraging behaviors are probably similar to that of
Idiurus macrotis
. Pygmy scaly-tailed flying squirrels eat fruit, nuts, tree gums, and bark, including
oil palm fruits.
Anomalurids
have relatively long digestive tracts, which allows for the maximum absorption of
nutrients.
- Plant Foods
- wood, bark, or stems
- seeds, grains, and nuts
- fruit
- sap or other plant fluids
Predation
There is little information on predators of pygmy scaly-tailed flying squirrels. Eagles
have been known to prey on other
scaly-tailed squirrel
species and it is likely that birds of prey and arboreal snakes prey on scaly-tailed
squirrels.
Ecosystem Roles
Anomularids
will chew off the tops of young, non-food tree species, resulting in a reduction
of competition for their favored trees species and a change in the composition of
forest trees. Pygmy scaly-tailed flying squirrels may also contribute to the dispersal
of forest tree seeds when they eat fruit.
In 1968, four individuals of
I. zenkeri
were found nesting in a tree on Dipikar Island with two individuals of
Anomalurus derbianus
.
- Lord Derby's scaly-tailed squirrels ( Anomalurus derbianus )
Economic Importance for Humans: Positive
Pygmy scaly-tailed flying squirrels are important members of their native ecosystems.
Economic Importance for Humans: Negative
Scaly-tailed squirrel
species will occasionally steal oil palm nuts, but they are not generally considered
pest species.
Conservation Status
In 1996,
I. zenkeri
was listed as lower risk/near threatened by the IUCN. This species is poorly known
and has since been re-categorized as data deficient.
Idiurus zenkeri
populations are negatively impacted by timber harvesting and destruction of habitat
for agriculture.
In order for informed conservation planning, information regarding a number of life history characteristics is required, including: population numbers, distribution, ecological interactions, and reproductive characters.
Other Comments
Studying anomularid species in the field is difficult, not only because they are nocturnal, but also because they are sensitive to the red lights that biologists use at night. Anomularids are not rare; they are only very difficult to study and observe.
Idiurus zenkeri
and feather-tailed gliders (
Acrobates pygmaeus
) are a remarkable example of convergence.
Additional Links
Contributors
Tanya Dewey (editor), Animal Diversity Web.
Mandie Cyr (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor, instructor), University of Wisconsin-Stevens Point.
- Ethiopian
-
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- terrestrial
-
Living on the ground.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- 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.
- 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.
- 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.
- 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).
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- viviparous
-
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- arboreal
-
Referring to an animal that lives in trees; tree-climbing.
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- social
-
associates with others of its species; forms social groups.
- colonial
-
used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- ultrasound
-
uses sound above the range of human hearing for either navigation or communication or both
- chemical
-
uses smells or other chemicals to communicate
- herbivore
-
An animal that eats mainly plants or parts of plants.
- frugivore
-
an animal that mainly eats fruit
- granivore
-
an animal that mainly eats seeds
References
Barnet, A. 2006. "Scaly-tailed squirrels" (On-line). Accessed October 10, 2006 at http://www.answers.com/topic/scaly-tailed-squirrels-anomaluridae-biological-family .
Booth, A. 1958. The Niger, the Volta and the Dahoney Gap as Geographic Barriers. Evolution , 12/1: 48-62.
Corbin, C., N. Cordeiro. 2006. Gliding characteristics of Lord Derby's Anomalure ( Anomalurus derbianus ) in Tanzania. African Journal of Ecology , 44: 106-108.
Haltenorth, T., H. Diller. 1977. The Collins Field Guide to the Mammals of Africa including Madagascar . Massachusetts: The Stephen Green Press.
Jones, C. 1971. Notes on the Anomalurids of Rio Muni and Adjacent Areas. Journal of Mammalogy , 52/3: 568-572.
Kingdon, J. 1974. East African Mammals . London: Academic Press.
Thorington, R. 2003. Idiurus zenkeri.
2006. "Flying Mouse" (On-line). Accessed October 10, 2006 at http://en.wikipedia.org/wiki/Flying_mouse .