Sciurus deppeiDeppe's squirrel

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Geographic Range

Tamaulipas, Mexico through most of the Yucatan Peninsula and to northwest Costa Rica. It is usually found at elevations between 300 and 3000 meters.

Reid (1997), Leopold (1959), Best (1995)

Habitat

Deppe's squirrel is locally common in areas of dense forest vegetation and high humidity. It is found in all kinds of tropical forest, including oak forest, pine-oak forest, cloud forest, ebony forest, and lowland forest. It disappears from areas that are highly disturbed by agriculture.

Reid (1997), Best (1995), Leopold (1959)

Physical Description

Head and body length: 181-225 mm

Tail length: 155-197 mm

Hind footh length: 46-55 mm

Ear length: 21-30 mm

Sciurus deppei (Deppe's squirrel) is a small squirrel. Its upperparts are brown, ranging from dark olive brown to reddish brown. Its underparts are paler, usually white or a pale shade of grey. The ears are medium-sized and without long tufts. The tail is short, narrow, and usually dark brown with a border of pale-tipped hairs. According to some reports, the forelegs and feet can be a shade of dark grey rather than brown.

Deppe's squirrel can be told from most other squirrels of this region by its small size, short tail, and medium-sized ears. It can be told apart from Sciurus richmondi and Sciurus granatensis by its pale, not orange, underparts.

Best (1995), Reid (1997)

  • Range mass
    191 to 219 g
    6.73 to 7.72 oz

Reproduction

Deppe's squirrel can breed year-round, but the average number of litters born each year is not known. Typically young are born at the end of the dry season, and the litter size varies between two and eight but is usually four. Males show enlarged testes when they are sexually active.

There is one report that Deppe's squirrel is able to breed with Sciurus yucatanensis, but it is not known whether or not the offspring were fertile.

Best (1995), Reid (1997), Leopold (1959), Gaumer (1917) in Leopold (1959)

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

Behavior

The squirrel is diurnal, spending most of its time in trees and sometimes descending to the ground to forage for food. Compared with other Sciurus species, Deppe's squirrel is less active and less often seen moving on small branches. It prefers moving on large branches, tree trunks, and through trees with a lot of cavities (such as strangler figs). When alarmed by movement, the squirrel moves to the opposite side of a tree trunk or branch and remains motionless. Ocasionally it will chatter at threatening animals.

In trees, the squirrel is found lower than 10 meters about 30% of the time, between 10 and 20 meters about 40 percent of the time, and higher than 20 meters about 30 percent of the time. It moves very quickly between trees and can make long-distance leaps between branches.

Because of its dark fur, the squirrel is rarely seen unless its in motion or silhouetted against leaves in the canopy. Deppe's squirrel is sometimes found in noisy groups of less than ten. Their call can be high-pitched like a bird's trill, but more frequently the call consists of several high chirps sounded close together. Despite their sometimes occuring in groups, Deppe's squirrel is not considered a social animal, and individuals are usually solitary.

Nests are made in tree trunks or formed out of leaves and twigs. Leaf nests are usually about 30 cm in diameter and at least 7.5 meters above the forest floor.

Estrada and Coates-Estrada (1985), Best (1995), Leopold (1959), Reid (1997)

Communication and Perception

Food Habits

Deppe's squirrel feeds on seeds, fruit, and foliage. Analysis of Deppe's squirrel diets have shown it eats figs, fungi, acorns, berries, and the fruits of trees such as Brosimum alicastrum, Cymbopetalum baillonii, Pinus caribea, Poulsenia armata, and Manilkara zapota. Most of the time it is an arboreal feeder, but it has been seen on the forest floor eating fungi, berries, and acorns.

Deppe's squirrel can do great damage to corn crops, especially when corn crops are situated in clearings of dense tropical forest. Deppe's squirrel eats the corn in a characteristic way, by cutting away a portion of the husk and eating only part of the corn ear beneath. Since Deppe's squirrels are too small to be a good food source, they are mainly killed to prevent crop damage.

Best (1995), Leopold (1950), Reid (1997), Estrada and Coates-Estrada (1985)

Economic Importance for Humans: Positive

There are no specific account of positive benefits for humans, but Deppe's squirrel may assist in the dispersal of tropical plant seeds and spores.

Economic Importance for Humans: Negative

Deppe's squirrel is known for the damage it can do to corn crops, but the squirrel is rarely found in highly agricultural areas. The damage it does to corn crops is usually confined to farms or milpas surrounded by undisturbed forest.

Leopold (1959), Best (1995)

Conservation Status

CITES Appendix III (Costa Rica). This species is only locally common to areas of undisturbed forest. Conservation of Deppe's squirrel will depend on conservation of its habitat.

Reid (1997)

Contributors

Elisabeth Witt (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

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

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.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

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.

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.

sexual

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

tactile

uses touch to communicate

References

Best, T. 1995. Sciurus deppei. Mammalian Species, 0(505): 1-5.

Estrada, A., R. Coates-Estrada. 1985. A preliminary study of resource overlap between howling monkeys Alouatta-palliata and other arboreal mammals in the tropical rainforest of Los-Tuxtlas Mexico. American Journal of Primatology, 9(1): 27-38.

Gaumer, G. 1917. Monografia de los mamiferos de Yucatan. Mexico City, Mexico: Departamento de Talleres Graficos de la Secretaria de Fomento.

Leopold, A. 1959. Wildlife of Mexico, the game birds and mammals. Berkeley, CA: University of California Press.

Reid, F. 1997. A Field Guide to the Mammals of Central America and Southeast Mexico. New York: Oxford University Press.