Callosciurus notatus

Geographic Range

Callosciurus notatus is found throughout the Oriental Region, including the Malay Peninsula, Borneo, Java, Sumatra, mainland southern Thailand, and other southeast Asian islands.

• Biogeographic Regions
• oriental oriental
  • native native

Habitat

Plantain squirrels can be found in many different tropical environments. They are arboreal, and found in plantations, scrub forests, gardens, rainforests, and mangrove forests. In inland forests they use both secondary and primary forests, but most activity is seen in the lower to middle stories. One study shows these squirrels at elevations from 500-1100 m, but they were found most often at 800 m. They have become urbanized in Singapore.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• rainforest rainforest
• scrub forest scrub forest

• Other Habitat Features
• urban urban
• agricultural agricultural

Physical Description

Plaintain squirrels are medium-sized squirrels with an olive-brown upperparts and tail. Their undersides are solid red-brown. The flank has a narrow black stripe which is superimposed on a buff one. Some subspecies have red hairs on the tip of their tail. Females have two or three mammae. They range from 160-259 g in weight. Measurements vary with subspecies, but lengths range from head and body 152-224 mm, tail 146-211 mm, and hind foot 38-47 mm.

Their dentition includes 2 large upper and lower incisors as seen in all rodents. There are 2 upper premolars and 1 lower premolar on each side of the jaw, and 3 upper and lower molars. No canines are present.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Multiple males compete in mating bouts for an estrus female. Usually 5 to 7 males compete in a single female’s home range. In the end, 2 to 4 males end up mating with a female. During this mating process, males communicate through barks and chasing. Vaughan et al. (2000) suggest a related Malaysian tree squirrel species, Calloscriurus caniceps , imitates predator calls to stop movements of the female and other males after copulation. By reducing their movements, these squirrels increase the probability of fertilization. This related species uses these calls for 30-35 minutes. Tamura et al. (1993) note that Callosciurus notatus , in contrast, only uses the call for 0.5-8.0 minutes.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Callosciurus notatus breeds year round, but pregnant females were found more often in the months of April-June and least often in October-December. The average litter size was 2.2 with a range of 1-4. Their nests are found in upper branches of large bushes or small trees, and consist of a sphere of twigs and leaves. Young are born with their eyes closed and are hairless. Callosciurus typically gestate for 40 days and infants weigh about 16 g. The close relative, Callosciurus prevosti reproduces after they are a year old and can have up to 3 litters per year. Juveniles leave the nest usually after 6 weeks.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

There is little research on parental investment in Callosciurus species. Females care for their young in a secure nest, nursing them until they reach independence.

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

Lifespan/Longevity

The longest a plantain squirrel has lived in captivity is 9.6 years. Lifespan in the wild is unknown, but other squirrel species live between 3 and 7 years in the wild.

Behavior

Plantain squirrels are diurnal and are usually found alone or in small groups. Their activity is usually related to foraging. In other species of the genus Callosciurus , male territories overlap more than females. Often, interactions between squirrels lead to “chase” sequences. In a related species, C. erythraeus , a dominance hierarchy exists in areas of food overlap and is based on age. It is suggested that adults give juveniles food.

• Key Behaviors
• arboreal arboreal
• scansorial
• diurnal diurnal
• motile motile
• sedentary sedentary
• solitary solitary
• territorial territorial
• dominance hierarchies dominance hierarchies

Home Range

Little research has been conducted relating to home ranges of C. notatus . Females usually show less overlap in their ranges than males.

The minimal convex polygon area (ha) for plantain squirrels was calculated in one study: adult males 0.70 +- 0.15 ha, adult females 1.84 +- 0.47 ha, subadult males 0.75 ha, and subadult females 0.79 +- 0.22 ha.

Communication and Perception

These squirrels communicated with a shrill, scolding chatter and a sibilant chirp, "tswit." While making these noises, they vigorously flourish their tail. These shrill cries were often in response to predators. Different predators elicit different calls. For example, the presence of a snake will cause squirrels of the genus Callosciurus to come closer and sometimes mob the snake.

• Communication Channels
• visual visual
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Callosciurus notatus is a frugivore and granivore. The diet of these squirrels includes fruit pulp, flowers, leafy shoots, seeds, and insects. Insects often make up half of stomach contents. Plantain squirels have also been known to extract sap or latex by gnawing on bark of trees, including rubber trees.

• Primary Diet
• omnivore omnivore

• Animal Foods
• insects

• Plant Foods
• leaves
• wood, bark, or stems
• seeds, grains, and nuts
• fruit
• flowers
• sap or other plant fluids

• Foraging Behavior
• stores or caches food stores or caches food

Predation

The most common predators for C. notatus are raptors, terrestrial carnivores, and snakes. Plantain squirrels often give different alarm calls depending on the predator. Each alarm call tends to give a different response. When a snake alarm call is made, these squirrels move in closer and sometimes engage in mobbing. The average number of plantain squirrels engaged in mobbing is 2.33. However, when a raptor is spotted, all activity ceases and immediate cover is taken. Their foraging habits vary by the type of predators in the area.

Ecosystem Roles

Plantain squirrels may occasionally disperse tree seeds. Several species of parasites have been found on C. notatus . Plantain squirrels also play important roles in ecosystems because they are prey for many predators.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Plantain squirrels are important members of the ecosystems in which they live.

Economic Importance for Humans: Negative

Plantain squirrels have been known to raid crops and may be considered agricultural pests in some areas.

• Negative Impacts
• crop pest

Conservation Status

Plantain squirrels are abundant throughout their range and adaptable, populations are not currently threatened.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Jim Constantine (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.

References

Becker, P., M. Leighton, J. Payne. 1985. Why Tropical Squirrels Carry Seeds Out of Source Crowns. Journal of Tropical Ecology , 1/2: 183-186.

Lekagul, B., J. McNeely. 1977. Mammals of Thailand . Bangkok: Darnsutha Press.

Medway, L. 1969. The Wild Mammals of Malaya (Penisular Malaysia) and Singapore. 2nd edition . Oxford: Oxford unviersity Press.

Nor, S., Z. Batine, Z. Akbar. 2001. "Online Journal of Biological Sciences" (On-line pdf). Elevation Diversity Pattern of Non-volant Small Mammals on Mount Nuang, Hulu, Langat, Selangor. Accessed March 24, 2006 at http://www.ansinet.org/fulltext/jbs/jbs1111081-1084.pdf .

Saiful, A., F. Hayashi, N. Tamura, Y. Rashid, A. Idris. 2001. Home Range Size of Sympatric Squirrel Species Inhabiting a Lowland Dipterocarp Forest in Malaysia. BioOne , 33/2: 346-351. Accessed April 17, 2006 at http://www.bioone.org.proxy.lib.umich.edu/perlserv/?request=get-document&issn=0006-3606&volume=33&page=346#I0006-3606-33-2-346-F01 .

Tamura, N., H. Yong. 1993. Vocalizations in response to predators in three species of Malaysian Callosciurus (Sciuridae). Journal of Mammalogy , 74/3: 703-714.

Tamura, N., F. Hayashi, K. Miyashita. 1988.

Dominance hierarchy and mating behavior of the Formosan squirrel Callosciurus erythraeus thaiwanensis

Tamura, N. 1993. Role of Sound Communication in Mating of Malaysian Callosciurus (Sciuridae). Journal of Mammalogy , 74/2: 468-478.

Tkach, V., R. Bray. 2001. Allassogonoporus callosciuri n. sp. (Digenea: Allassogonoporidae) from the plantain squirrel Callosciurus notatus (Boddaert) (Rodentia: Sciuridae) in Borneo.

Systematic Parasitology

Vaughan, T., J. Ryan, N. Czaplewski. 2000. Mammalogy . United States: Brooks/Cole.

2005. "SCIRUS (Elsevier)" (On-line).

Prevost's Squirrel

2005. "SCIRUS (Elsevier)" (On-line). Mammals of Southeast Asia : Plantain Squirrel - Callosciurus notatus. Accessed April 17, 2006 at http://www.ecologyasia.com/verts/mammals/plantain_squirrel.htm .