Dremomys rufigenis

Geographic Range

Red-cheeked squirrels ( Dremomys rufigenis ) occur in southern China and northeastern South Asia, to the west of the Indian subcontinent, and to the western Indochinese Peninsula and the northern-to-middle Malay Peninsula. They are found in many protected areas in Southeast Asia.

• Biogeographic Regions
• palearctic palearctic
  • native native
• oriental oriental
  • native native

Habitat

Red-cheeked squirrels are a half-terrestrial and half-arboreal species that are found in low and high elevations, with an upper limit of 1,500 m. They live in tropical evergreen forests and shrublands. They are most active between the ground and about four feet off the ground. They have been observed to go up to the forest canopy to eat ripe fruit. They are also found in degraded and fragmented habitats.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• mountains mountains

Physical Description

There is limited available information on body masses and body lengths of red-cheeked squirrels. According to a study by Koyabu et al. (2012), the mean body weight of wild adult red-cheeked squirrels sampled in Vietnam (n = 11) was 221 g. According to Hayssen (2008b), the body mass of any squirrel can be predicted from body length using this equation: log10 body mass = −4.30 + 2.91(log10 body length) − 0.07(Pteromyini) (1 is substituted for Pteromyini when the animals is a flying squirrel and 0 if it is not). When the mean body weight of 221 g is fitted to this equation (Pteromyini = 0), the body length is estimated to be 192 mm. Red-cheeked squirrels have a grey brown body color. They have long necks, which are thought to help them search for insects and invertebrates on the ground. Their long splanchnocranium, a portion of a skull that comprises the mandibular, hyoid, and gill arches, helps insectivorous foraging behaviors on land. It is described that the skull sizes of populations in Malaysia are larger than those of the populations in Vietnam, Laos and Thailand. Species in the genus Dremomys typically have elongated rostra and short bushy tails.

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

Reproduction

There is little available information on reproduction in red-cheeked squirrels. It is known that the mating system of squirrels (Family Sciuridae ) is polygynandrous; both males and females mate with multiple partners during a single breeding season. Therefore, a single litter usually has young from multiple fathers.

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

There is little available information on general reproductive behavior in red-cheeked squirrels. For squirrels in general, sexual maturity occurs when males develop their testes females enter estrus. Males typically chase females to mate during the breeding season. Litter sizes of two species in the same genus as red-cheeked squirrels were reported by Hayssen (2008ab); litter sizes for orange-bellied Himalayan squirrels ( Dremomys lokriah ) averaged 3.67, while litter sizes for Perny's long-nosed squirrels ( Dremomys pernyi ) average 4.00.

• Key Reproductive Features
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual

There is little available information on parental care in red-cheeked squirrels. It is known that all squirrels give birth to litters in a nest and they are born altricial. Therefore, female parental care of the young, such as lactating and providing food is important. Also, squirrels are polygynandrous, so males cannot confirm whether offspring are theirs or not. Therefore, parental care by males is not very likely.

• Parental Investment
• altricial altricial
• female parental care female parental care

Lifespan/Longevity

The lifespan of red-cheeked squirrels is about four years.

Behavior

Red-cheeked squirrels are diurnal. They are active both on the ground and in trees, and are most active at heights below four feet. Little has been investigated about the behavior of this species or this genus, but tree squirrels are known to be generally solitary, unlike ground squirrels. Also, tree squirrels are very agile when moving among trees. Squirrels in general are known to be territorial.

• Key Behaviors
• arboreal arboreal
• terricolous
• diurnal diurnal
• motile motile
• territorial territorial

Home Range

There is little available information on home ranges for red-cheeked squirrels.

Communication and Perception

There is little available information on communication in red-cheeked squirrels. In general, squirrels have several kinds of vocalizations for various situations, such as when young call their mothers, when adult males attract females during the breeding season, and when individuals alarm each other of danger. Squirrels also communicate with each other using certain postures, movements, and pheromones.

• Communication Channels
• visual visual
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• pheromones pheromones

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

Food Habits

Red-cheeked squirrels are both insectivorous and frugivorous, which is consistent with other tree squirrels. However, it is known that they avoid hard seeds and tough tree bark. This is different from Pallas's squirrels ( Callosciurus erythraeus ), which are one of the tree squirrels that eat insects and fruits, and have an overlapping range of red-cheeked squirrels.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
• herbivore herbivore
  • frugivore frugivore
• omnivore omnivore

• Animal Foods
• insects

• Plant Foods
• fruit

Predation

There is little available information about predation on red-cheeked squirrels. However, it is known that predators of squirrels include cats, canids, weasels and birds of prey, such as eagles, hawks, falcons, and owls. Common anti-predator adaptations of squirrels are camouflage and escape. The body color of many of squirrels matches the surrounding environment, which helps them hide from predators. The body color of red-cheeked squirrels is grey brown, which is thought to blend well into the forest background. Also, squirrels run away quickly when they detect predators.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

There is little available information on ecosystem roles in red-cheeked squirrels. Squirrels in general have multiple ecosystem functions. First, they serve as important prey for various predators, including threatened or endangered species. Also, tree squirrels in particular help disperse seeds through their caching activities. At the same time, tree squirrels are major predators of seeds. They often consume seeds in trees before seeds are fully mature, which can have a negative influence on trees via bark stripping and twig clipping. However, these features may not apply to red-cheeked squirrels, since it is reported that they avoid hard seeds and tough tree bark. In addition, squirrels are host to various parasites, including mites and ticks.

• Ecosystem Impact
• parasite parasite

Economic Importance for Humans: Positive

Red-cheeked squirrels are harvested for food. Particularly, this species is heavily hunted in Lao PDR and in some neighboring countries.

• Positive Impacts
• food food

Economic Importance for Humans: Negative

There are no known adverse effects of red-cheeked squirrels on humans.

Conservation Status

The population of red-cheeked squirrels is currently stable and this species is listed as Least Concern on the IUCN Red List. No major threats are detected in this species in Southeast Asia. However, this species is data deficient regarding population sizes and densities, so their conservation status might not be accurate enough. Given that this species is hunted for food, more rigorous monitoring of populations is important.

Other Comments

There are six species under the genus Dremomys (plain long-nosed squirrels).

Additional Links

Encyclopedia of Life

Contributors

Yuka Sugiura (author), University of Washington, Laura Prugh (editor), University of Washington, Galen Burrell (editor), Special Projects.

References

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