Horse-tailed squirrels feed on seeds, fruits, and arthropods. In Malaysia they are reported to feed on bark and sap, while sympatric beautiful squirrels (Callosciurus species) feed more opportunistically on different plant material and insects (McKinnon in McDonald, 2001). Like other squirrels, they may include a diversity of foods in their diet, such as eggs, young vertebrates, and fungi.
Animal Foods: insects; terrestrial non-insect arthropods
Plant Foods: leaves; wood, bark, or stems; seeds, grains, and nuts; fruit; sap or other plant fluids
Primary Diet: herbivore (Frugivore , Granivore )
Horse-tailed squirrels avoid predation primarily through their agility and vigilance in the trees. Few predators can chase and capture adults the forest canopy. Young squirrels are vulnerable to predation in the nest by small, arboreal predators such as snakes, cats, or other squirrels. Their coloration may make them cryptic in the forest canopy.
Sundasciurus hippurus is the largest and most colourful of the Sunda tree squirrels, Sundasciurus, with considerable geographical colour variation in Borneo. This medium-sized squirrel always has a grey head, shoulders, and fore feet. This grey pelage may be more or less grizzled. The upperparts are reddish brown to chestnut. Subspecies differ, the hindlegs may be grey or reddish brown and the underside is whitish, dull orange, or reddish brown. The tail is glossy black or grey and black banded. Despite the common name, horse-tailed squirrel, the tail is not very similar to that of a horse. There are some individuals resembling Callosciurus erythraeus. But in northern Malaysia, where both species occur, horse-tailed squirrels have uniform red undersides, not agouti, and darker and more bushy tails. (Payne, 1985, Lekagul & McNeely, 1977 ; Medway, 1978 ; Corbet & Hill, 1992)
Head and body length ranges from 21.5 cm to 25 cm and tail length from 24 to 29 cm. Hind foot length measures from 54 to 64 mm. They weight from 260 to 420 g. (Lekagul & McNeely, 1977; Medway, 1978)
The dental formula is 1/1 0/0 2/1 3/3 = 22. (Payne, 1985)
Range mass: 260 to 420 g.
Range length: 21.5 to 25 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry ; polymorphic
Sexual Dimorphism: sexes alike
Lifespan is unknown in these squirrels. Most squirrel species have lifespans averaging 3 to 7 years.
Range lifespan
Status: captivity: 14 (high) years.
Sundasciurus hippurus is most often seen in lowland primary forest but has been found in re-grown logged forests and secondary forests. (Medway,1978; Payne,1985).
Range elevation: 1500 (high) m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: rainforest
Sundasciurus hippurus is distributed on the Malay Peninsula, Sumatra, Borneo, and the Rhio Archipelago (Corbet & Hill, 1992; Nowak, 1997). A record in South Vietnam, as listed in Wilson & Reeder (1993) seems very doubtful (see other comments). There are no reliable records north of the Isthmus of Kra. In Malaysia they are distributed up to 1000 m and in Borneo up to 1500 m.
Biogeographic Regions: oriental (Native )
Horse-tailed squirrels are important seed dispersers in primary and secondary lowland forests throughout their range. They may also serve as an important prey base for large predators, such as raptors.
Ecosystem Impact: disperses seeds
Horse-tailed squirrels may help to disperse the seeds of important lowland tree species.
There are no negative impacts of horse-tailed squirrels on humans.
Horse-tailed squirrels have no special status, although they may be threatened by habitat destruction throughout their range.
US Migratory Bird Act: no special status
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: near threatened
The most commonly heard call is "CHEK!.....CHEK!.......chekchekchekchek....." (Payne,1985)
Horse-tailed squirrels probably also communicate through visual, chemical, and tactile cues. Diurnal tree squirrels typically have exceptional vision and vibrissae on the chin and limbs that aids in the perception of surfaces, making these animals quite agile climbers.
Communication Channels: visual ; tactile ; acoustic ; chemical
Perception Channels: visual ; tactile ; acoustic ; chemical
The distribution in South Vietnam (Dao & Cao, 1990) may be not reliable. According to Lunde & Son (2001) the specimens in the Hungarian Museum of Natural History are Sundasciurus hippurus, but they question the validity of the record “Saigon”. They suggest that these animals were from animal dealers from further south. Hence the distribution in Vietnam has yet to be confirmed (Lunde & Son, 2001).
Very little is known about mating behavior and systems in Sundasciurus species.
Females have two or three pairs of mammae. Little is known of reproduction in these squirrels but perhaps, as in other diurnal squirrels in that region, they produce young throughout the year. Two close relatives, Sundasciurus lowii and S. tenuis, have litter sizes of 2 to 4.
Breeding season: These squirrels probably breed throughout the year.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Little is known of parental investment in these squirrels. Females care for and nurse their offspring until independence in a tree nest.
Parental Investment: no parental involvement; altricial ; pre-fertilization (Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)
The horse-tailed squirrel (Sundasciurus hippurus) is a species of rodent in the family Sciuridae. It is found throughout the islands of Borneo and Sumatra, as well as the southern half of the Malay Peninsula, which includes the entire nations of Brunei and Malaysia, as well as some areas of Indonesia and Thailand. There was a mention of this squirrel being found in Vietnam in 1831 (I. Geoffroy, 1831), but subsequent descriptions of this squirrel's range have not included that nation.[2]
The horse-tailed squirrel is the most colorful and largest of the Sundasciurus tree squirrels. It is a medium-sized squirrel with a head-to-body length of 21.5 to 25 cm (8.5 to 9.8 in) and a tail length of 24 to 29 cm (9.4 to 11.4 in). The horse-tailed squirrel has a grizzled grey head, shoulders, forefeet and body with a whitish, dull orange, or red-brown underbelly. The tail of this squirrel is commonly a glossy black or grey banded with black.[3]
The horse-tailed squirrel (Sundasciurus hippurus) is a species of rodent in the family Sciuridae. It is found throughout the islands of Borneo and Sumatra, as well as the southern half of the Malay Peninsula, which includes the entire nations of Brunei and Malaysia, as well as some areas of Indonesia and Thailand. There was a mention of this squirrel being found in Vietnam in 1831 (I. Geoffroy, 1831), but subsequent descriptions of this squirrel's range have not included that nation.
