Geographic Range
Western Ghats squirrels (
Funambulus tristriatus
) are native to the Western Ghats in southwest India. They have also been observed
in Kerala, Maharashtra, Karnataka, and Tamil Nadu.
Habitat
Western Ghats squirrels are found in moist deciduous forests, evergreen rainforests,
pasturelands and cardamom, tea, and coffee plantations at elevations of 700 to 2100
m. They live in dense, higher elevation regions of canopy in moist deciduous forests.
- Habitat Regions
- tropical
- terrestrial
- Terrestrial Biomes
- forest
- rainforest
- Other Habitat Features
- agricultural
Physical Description
The tail length of species in
Funambulus
is roughly equal to the head and body length, which ranges from 115 to 178 mm, Total
body length (body plus tail) ranges from 230 to 356 mm.
Funambulus tristriatus
is the biggest species in the genus
Funambulus
. It has a full tail and dark body. In the dorsal fur there are three longitudinal,
lightly colored stripes. The head is grayish or reddish brown and the dorsal body
is pale grayish brown to nearly black. There is no information available about the
basal metabolic rate. A study found the body mass of
Funambulus tristriatus
to range from 45 to 215 g.
- Other Physical Features
- endothermic
- homoiothermic
- bilateral symmetry
Reproduction
The mating system of Western Ghats squirrels is not known. When mating, they engage
in chasing and the male smells the female's external genitalia and face. If multiple
males are interested in the same female, fighting among the males occurs. The winner
of the contest then voices a ‘chi-chi’ mating call and mates with the female.
Western Ghats squirrels breed all year long but more breeding occurs throughout the
summer between December and May. There is much less breeding during the rainy season
between June and August. Western Ghats squirrels reach sexual maturity at approximately
6 to 11 months. The average number born in a litter is 2.6. There is little information
available about the gestation period, but the gestation period of a close relative,
Funambulus pennantii
, is 40 to 45 days. The weaning age is approximately 60 days. There is little known
about the age of independence. There was speculation in a study conducted in 1984
that resorption of embryos may occur in females because, during the study, many females
had three embryos, but did not give birth to three young. That study also found the
birth mass to be 4.5 to 7.25 g.
- Key Reproductive Features
- iteroparous
- year-round breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- viviparous
Little is known about the exact duration of parental investment in Western Ghats squirrels,
however the young do not start eating solid food until approximately two months old.
Female Western Ghats squirrels raise their young in a nest that they build. When Western
Ghats squirrels are born, their eyes are shut and they are naked except for vibrissae.
- Parental Investment
- altricial
- female parental care
-
pre-fertilization
- provisioning
-
protecting
- female
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
provisioning
Lifespan/Longevity
Lifespan of Western Ghats squirrels is not reported in the literature.
Behavior
Western Ghats squirrels are diurnal rodents. Little is known about their social system.
However, a close relative, northern palm squirrels (
Funambulus pennantii
) are gregarious. Western Ghats squirrels are arboreal but they spend a lot of time
on the ground foraging. Both males and females build nests out of fibrous materials
on tree branches. Females and males do not share nests. Males mainly rest in their
nests while females use their nests for resting and raising young.
Home Range
Little is known about the home range of Western Ghats squirrels, but the average home
range of a close relative,
Funambulus pennantii
, is 0.15 hectares for females and 0.21 hectares for males.
Communication and Perception
Most reports of communication in Western Ghats squirrels involve communication during
mating. Mates engage in chasing and males use a ‘chi-chi’ mating call and smell the
female's external genitalia and face before mating. Western Ghats squirrels are likely
to have keen senses of smell, vision, and touch, like most other squirrels.
Food Habits
Western Ghats squirrels consume mostly plant material, including coconut palm (the
male flowers), cacao (
Theobroma cacao
), fruits, such as mango, guava and grapes, and grains, such as rice. These squirrels
eat many insects, including caterpillars, beetles, and termites. Other squirrels in
the genus
Funambulus
also eat bark, leaves, nuts, seeds and plant stems.
- Primary Diet
- omnivore
- Animal Foods
- insects
- Plant Foods
- leaves
- wood, bark, or stems
- seeds, grains, and nuts
- fruit
- flowers
Predation
There is nothing known about predation on Western Ghats squirrels. Raptors and large,
arboreal snakes are likely to prey on these squirrels. Western Ghats squirrels probably
avoid most predation by being vigilant and arboreal.
Ecosystem Roles
Little is known about symbiotic relationships between Western Ghats squirrels and
other species. Individuals are probably food for predators such as birds of prey and
snakes in the area, and they consume plant material and insects. They may play a role
in seed dispersal, although there are no reports of this.
Economic Importance for Humans: Positive
Western Ghats squirrels consume termites, beetles, and caterpillars, which are crop
pests in the areas they live.
- Positive Impacts
- controls pest population
Economic Importance for Humans: Negative
Western Ghats squirrels consume commercial crops such as cacao.
- Negative Impacts
- crop pest
Conservation Status
Western Ghats squirrels are listed as a species of least concern on the IUCN red list.
Additional Links
Contributors
Emily Oja (author), Michigan State University, Barbara Lundrigan (editor), Michigan State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
- oriental
-
found in the oriental region of the world. In other words, India and southeast Asia.
- 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.
- agricultural
-
living in landscapes dominated by human agriculture.
- 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).
- year-round breeding
-
breeding takes place throughout the year
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- viviparous
-
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- 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.
- female parental care
-
parental care is carried out by females
- arboreal
-
Referring to an animal that lives in trees; tree-climbing.
- diurnal
-
- active during the day, 2. lasting for one day.
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- omnivore
-
an animal that mainly eats all kinds of things, including plants and animals
References
Abrol, D. 2014. Integrated Pest Management: Current Concepts and Ecological Perspective . Paris: Academic Press.
Advani, R., A. Sujatha. 1984. Body weights, sex ratio and population structure of the Western ghat squirrel, Funambulus tristriatus. Proceedings - Indian Academy of Sciences: Animal Sciences , 93/5: 491-496.
Bhat, S. 1985. Food and nesting habits of the Western Ghats squirrel, Funambulus tristriatus Waterhouse. The Journal of the Bombay Natural History Society , 82: 837-843.
Bhat, S., D. Mathew. 1984. Observations on the breeding biology of the Western Ghats squirrel, Funambulus tristriatus Waterhouse. Mammalia , 48/4: 573-584.
Bhat, S. 1980. Cannibalistic Behavior in Captive Western Ghats Squirrel, Funambulus Tristriatus Waterhouse. Comparative physiology and ecology , 5/1: 44-45.
Chakravarthy, A., N. Thyagaraj, L. Kumar, A. Girish. 2008. Crop raiding and management of Funambulus palmarum in cardamom (Eletteria cardamomum) plantations of Western Ghats of Karnataka, south India. Current Science , 95/7: 907-911.
Chandrasekar-Rao, A., M. Sunquist. 1996. Ecology of small mammals in tropical forest habitats of southern India. Journal of Tropical Ecology , 12/4: 561-571.
Molur, S., P. Nameer. 2008. "Funambulus tristriatus" (On-line). IUCN Red List of Threatened Species. Accessed March 02, 2014 at http://www.iucnredlist.org/details/8704/0 .
Moore, J., G. Tate. 1965. A study of the diurnal squirrels, Sciurinae, of the Indian and Indochinese subregions. Fieldiana Zoology , 48: 1-351.
Nowak, R. 1999. Walker's Mammals of the World . Baltimore and London: The Johns Hopkins University Press.