Sciurus variegatoides

Geographic Range

Variegated squirrels ( Sciurus variegatoides ) are found in North and Central America, from southern Chiapas, Mexico to Central Panama.

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Sciurus variegatoides occupies both dry and wet tropical forests, but prefers open, arid environments. It is found in deciduous, semi-deciduous, and, at times, evergreen forest. It is frequently found in open woodland, scrubland, and plantations. It lives at elevations ranging from sea level to 2500 m.

• Habitat Regions
• tropical tropical

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

• Other Habitat Features
• agricultural agricultural

Physical Description

Sciurus variegatoides is a large, long-tailed species of tree squirrel. Its pelage is shiny and bristly. The fourteen different subspecies exhibit a wide range of color and color pattern. Dorsally, the color ranges from blackish to reddish brown to yellowish-gray to white. On the underside, the color ranges from white to cinnamon-buff. The feet and sides of the body are pale gray or yellowish; the ears have a pale patch of fur on the outside. Different subspecies may have a combination of dorsal and lateral stripes and forehead patches or may be completely grizzled in coloration. The guard hairs on the back and sides are agouti, and are made up of several different color bands. The underside is not usually banded. The tail is bushy and long and has black hairs tipped in white on its dorsal side. The underside of the tail is usually lighter in color.

There is little seasonal change in the coat of S. variegatoides . It has no melanistic phase. Molts begin in April or May, and the new pelage is in by September and October. There is considerable variation in time of molt, with individuals in molt occurring every month of the year. An individual may only molt once a year. The darkest subspecies are found in the areas with the greatest rainfall, along the Caribbean coast ( S. v. belti , S. v. managuensis , S. v. artrirufus , and S. v. thomasi ). Lighter subspecies are found along the Pacific side of Central America ( S .v. bangsi , S. v. dorsalis , S. v. goldmani , and S. v. helveolus ).

The dental formula for variegated squirrels is I 1/1, C 0/0, P 2/1, M 3/3, total 22. There is no size difference between males and females, although there is considerable variation among individuals of the same subspecies in the same location. Head and body length varies from 220 to 337 mm. Tail length varies from 226 to 325 mm. Length of the hind foot is from 45 to 70 mm. Length of the ear is 20 to 35 mm. Variegated squirrels weigh from 428 to 909 g. Measurements of bacula are as follows: length is 12.1 mm, length of tip is 2.6 mm, height of tip is 3.0 mm, height of base is 3.0 mm, and width of base is 2.4 mm. Measurements of baubella are as follows: length is 3.9 mm and width of disc is 2.0 mm. Females have eight mammae; one pair pectoral, two pair abdominal, and one pair inguinal.

Variegated squirrels are similar to many other tree squirrel species. There are some distinguishing characteristics however. The red-tailed squirrels have an orange tail, are smaller, and occur in denser, wetter forests; Deppe's squirrels have a slender tail, gray underside and feet, and are smaller; Yucatan squirrels are gray and smaller; Mexican gray squirrels lack the prominent pale ear patches.

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

• Sexual Dimorphism
• sexes alike

Reproduction

Little is known about the mating system of S. variegatoides , but most tree squirrels ( Sciurus ) are similar in their mating and reproduction. Tree squirrels are generally solitary, with individuals coming into contact only to mate. Social ranking of tree squirrels is based on weight and age. The higher ranking males will have more mates. A female tree squirrel goes into estrus once a year for the duration of one day. Through olfactory cues and behavioral changes, males know when to mate with her. More than one male may enter the territory of a female in estrus, and males may fight one another in order to mate. After mating, the male and female separate. There are no lasting pair bonds.

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

In Panama, breeding occurs annually for S. variegatoides between April and May. Female variegated squirrels build nests high up in the trees and have their babies there. Nest materials include twigs and leaves, and nests are usually waterproof. The average number of young per litter ranges from 2 to 8. Young born to the subspecies S. v. melania have the characteristic dark color of the adult.

In Sciurus , gestation lasts between 33-46 days. When tree squirrels are born, they are blind and naked. Their digits are fused together, and they weigh less than one ounce. After 4 days, babies are vocal, emitting squeaks in response to their mother’s stimuli. After 2 weeks, they begin to develop fur. Between 30 to 32 days babies develop teeth and open their eyes. By 4 weeks, the young are learning to groom themselves, and they leave the nest by 6 weeks. Squirrels begin to socialize at 10 weeks just after they are weaned. They are solitary by 15 weeks. Tree squirrels reach sexual maturity between 12 to 15 weeks.

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

Little is known about parental investment in the species S. variegatoides . In most members of the genus Sciurus , the father offers no parental care. The mother builds a nest for her young and they reside there until 6 weeks. The mother will cover her nest with brush, in order to protect her young, while she is scavenging for food. Young tree squirrels are weaned at 10 weeks and are independent of their mother after 15 weeks. The mother is responsible for showing the young how to scavenge for food and groom.

• Parental Investment
• altricial altricial
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • protecting
    • female
• extended period of juvenile learning

Lifespan/Longevity

For the genus, the longest living Sciurus was 23 years in captivity and 8 to 12 years in the wild.

Behavior

Variegated squirrels are solitary, arboreal mammals. They build nests in tall, slender trees usually at the junction between a limb and the main trunk of the tree. There is approximately one nest per 2.4 ha. The squirrels are diurnal, being most active during the early morning. They spend almost all of their time in the trees and are very agile, running and leaping from one branch to the next with ease. They cross open areas via fence rows and lower trees.

Members of the genus Sciurus do not hibernate, but they may remain inactive during periods of cold or inclement weather until they need food. In general, interspecific competition is averted by maintaining strict niches where species overlap.

• Key Behaviors
• arboreal arboreal
• scansorial
• saltatorial saltatorial
• diurnal diurnal
• motile motile
• solitary solitary

Home Range

In general, males of the genus Sciurus have larger home ranges than females, and they may overlap with those of other males and females. The home ranges of females do not overlap and are generally smaller.

Communication and Perception

Variegated squirrels make chucking sounds when alarmed. Harsh chatter is also occasionally heard. Female tree squirrels use chemical cues to show males when they are ready to mate.

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

• Other Communication Modes
• pheromones pheromones

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

Food Habits

Sciurus variegatoides consumes nuts and fruits of various kinds, including hard-shelled and soft, thin-shelled seeds of fruits such as Scheelea rostrata , Scheelea zonensis , Crescentia alata , Guazuma ulmifolia , Quercus oleoides , Sterculia apetala , Mangiferea indica , Spondias mombin , Bursera simaruba , Ochroma pyramidale , Cochlospermum vitifolium , Enterolobium cyclocarpum , Cecropia , Ficus insipida , Astrcarum standleyanum , Scheelea zonensis , Genipa americana , Apeiba tibourbou , Luehea speciosa , and Trema micrantha . It spends most of its time foraging for soft, juicy fruits. It also eat some vines, flowers, and fungi.

• Primary Diet
• herbivore herbivore
  • frugivore frugivore
  • granivore granivore

• Plant Foods
• seeds, grains, and nuts
• fruit
• flowers

• Other Foods
• fungus

Predation

The predators of S. variegatoides are generally opportunistic. The following information is in regards to the genus Sciurus : Predators of adult tree squirrels include weasels ( Mustela ), martens ( Martes ), wildcats ( Felidae ), foxes ( Canidae ), eagles ( Accipitridae ), owls ( Strigiformes ), and snakes ( Serpentes ). These predators may also feed on young, taking them directly from the nest.

Ecosystem Roles

Sciurus variegatoides serves an important role in seed dispersal via the fruit it consumes. Ectoparasites of variegated squirrels include chiggers and lice . No endoparasites are known.

Ectoparasites of tree squirrels (genus Sciurus ) include Acari , Anoplura , Siphonaptera , and Diptera . Endoparasites include Protozoa , Cestodes , and Nematodes .

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

Variegated squirrels are hunted by humans for sport and for meat.

• Positive Impacts
• food food

Economic Importance for Humans: Negative

Variegated squirrels are considered crop pests in some areas.

• Negative Impacts
• crop pest

Conservation Status

There is no special conservation status for variegated squirrels . This species may be considered "fragile" in some parts of its range in Mexico.

Other Comments

Some commonly used names for S. variegatoides include ardilla jaspeada, chiza, and ardilla negra. Sciurus comes from the Latin word meaning squirrel and variegatoides signifies the variable coloration of the species.

Additional Links

Encyclopedia of Life

Contributors

Matthew Wund (editor), University of Michigan-Ann Arbor.

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

References

Best, T. 1995. Mammalian Species: Sciurus variegatoides. The American Society of Mammalogists , 500: 1-6. Accessed March 20, 2004 at http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/ .

Eisenberg, J. 1989. Mammals of the Neotropics . Chicago: University of Chicago Press.

Emmons, L. 1990. Neotropical Rainforest Mammals: A Field Guide . Chicago: University of Chicago Press.

Gurnell, J. 1987. The natural history of squirrels . New York: Facts on File.

Harris, W. 1937. Revision of Sciurus variegatoides, a species of Central American squirrel. Miscellaneous publications, University of Michigan, Musuem of Zoology , 38: 5-39.

Klein, E. 1977. Mamiferos de Honduras . Tegucigalpa, D.C.: Secretaria de Recursos Naturales.

Reid, F. 1997. A field guide to the mammals of Central America and Southeast Mexico . New York: Oxford University Press.

Walker, E. 1983. Walker's Mammals of the World . Baltimore: Johns Hopkins University Press.