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Funambulus tristriatusjungle palm squirrel

By Emily Oja

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. (Abrol, 2014; Molur and Nameer, 2008; Moore and Tate, 1965; Nowak, 1999)

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. (Chandrasekar-Rao and Sunquist, 1996; Molur and Nameer, 2008; Moore and Tate, 1965)

  • Range elevation
    700 to 2100 m
    2296.59 to 6889.76 ft

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. (Abrol, 2014; Advani and Sujatha, 1984; Chandrasekar-Rao and Sunquist, 1996; Moore and Tate, 1965; Nowak, 1999)

  • Range mass
    45 to 215 g
    1.59 to 7.58 oz
  • Range length
    230 to 356 mm
    9.06 to 14.02 in

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. (Bhat and Mathew, 1984)

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. (Abrol, 2014; Bhat and Mathew, 1984; Molur and Nameer, 2008; Nowak, 1999)

  • Breeding interval
    Western Ghats squirrels breed throughout the year, although breeding is concentrated in one season.
  • Breeding season
    Mating occurs year round, though during the rainy season from June to August there are fewer pregnant females and there are many more pregnancies during December through May.
  • Average number of offspring
    2.6
  • Average weaning age
    60 days
  • Range age at sexual or reproductive maturity (female)
    6 to 11 months
  • Range age at sexual or reproductive maturity (male)
    6 to 11 months

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. (Bhat and Mathew, 1984; Bhat, 1985)

  • Parental Investment
  • altricial
  • female parental care
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female

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. (Advani and Sujatha, 1984; Bhat, 1980; Bhat, 1985; Chandrasekar-Rao and Sunquist, 1996; Molur and Nameer, 2008; Nowak, 1999)

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. (Nowak, 1999)

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. (Bhat and Mathew, 1984)

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. (Advani and Sujatha, 1984; Bhat, 1985; Nowak, 1999)

  • 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. (Chakravarthy, et al., 2008)

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. (Bhat, 1985; Chakravarthy, et al., 2008; Nowak, 1999; Abrol, 2014; Advani and Sujatha, 1984; Bhat, 1985; Chakravarthy, et al., 2008; Nowak, 1999)

Economic Importance for Humans: Positive

Western Ghats squirrels consume termites, beetles, and caterpillars, which are crop pests in the areas they live. (Bhat, 1985)

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

Western Ghats squirrels consume commercial crops such as cacao. (Abrol, 2014; Bhat and Mathew, 1984; Bhat, 1985)

  • Negative Impacts
  • crop pest

Conservation Status

Western Ghats squirrels are listed as a species of least concern on the IUCN red list. (Molur and Nameer, 2008)

Contributors

Emily Oja (author), Michigan State University, Barbara Lundrigan (editor), Michigan State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

Glossary

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

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

diurnal
  1. active during the day, 2. lasting for one day.
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.

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).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

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.

sedentary

remains in the same area

sexual

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

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.

year-round breeding

breeding takes place throughout the year

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. 1980. Cannibalistic Behavior in Captive Western Ghats Squirrel, Funambulus Tristriatus Waterhouse. Comparative physiology and ecology, 5/1: 44-45.

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. 1985. Food and nesting habits of the Western Ghats squirrel, Funambulus tristriatus Waterhouse. The Journal of the Bombay Natural History Society, 82: 837-843.

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.

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