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Heliosciurus mutabilismutable sun squirrel

By Britney Frei

Geographic Range

Heliosciurus mutabilis (mutable sun squirrel) can be found in East Africa in the Ethiopian region. Its range extends south from Tanzania to southern Mozambique and west toward the Chimanimani Highlands of Zimbabwe, south-central Zambia and Malawi. (Grubb and Kerbis Peterhans, 2008)

Habitat

Mutable sun squirrels can be found in a variety of habitats, including lowland evergreen forests, thickets and riverine forests of the Brachystegia/Julbernardia woodland association and moist savanna and grasslands. When looking for suitable nest sites, mutable sun squirrels seek out holes in trees or dense clumps of vines. (Grubb and Kerbis Peterhans, 2008)

Physical Description

Mutable sun squirrels are among the largest squirrels in their range. They have agouti-banded hairs in their pelage. The number of bands differ from one part of the body to another. Body hairs have two light bands and three dark bands, including the base of the hair shaft and the tip. Tail hairs have three to 12 bands and end always with a dark tip. Pelt coloration changes between molts. In young mutable sun squirrels, the dark hair bands are blackish brown and the light hair bands are whitish ochre. The dark bands fade with age, lightening to a brownish maroon. Eventually, both the dark and light bands become a light reddish ochre hue and are difficult to tell apart. This change in pelt color reflects the origin of the name: mutable sun squirrels lay out in the sun, which results in the changing of the hair color. (Grubb, 1982; Nowak, 1999)

  • Range mass
    250 to 340 g
    8.81 to 11.98 oz
  • Range length
    211.8 to 250.0 mm
    8.34 to 9.84 in

Reproduction

There is little available information on reproduction in mutable sun squirrels. However, in Heliosciurus rufobrachium, males and females are often found in pairs, suggesting the possibility that stable mating pairs are established.

Reproduction in mutable sun squirrels has not been well studied. In eastern Zimbabwe, a pregnant female was found carrying 4 young in August. In western Africa, other Heliosciurus species have two breeding seasons. (Thorington, et al., 2012)

  • Breeding interval
    Breeding intervals in mutable sun squirrels have not been reported.
  • Breeding season
    The breeding season of mutable sun squirrels has not been reported.

There is little available information on parental investment in mutable sun squirrels. However, as in most mammals, females are likely to take on the majority of investment in the young.

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

Lifespan/Longevity

There is little available information on longevity in mutable sun squirrels. However, an individual Heliosciurus gambianus was reported to have lived almost 9 years. (Nowak, 1999)

Behavior

Mutable sun squirrels can be found in pairs or alone. They are social and diurnal. Mutable sun squirrels are most active during the morning and evening hours. They spend the hottest part of the day sunning themselves on tree limbs. The name "sun squirrel" comes from this behavior. Mutable sun squirrels are an arboreal species specialized for climbing trees. However, they can also be found foraging for seeds, nuts, and insects on the ground. (Grubb and Kerbis Peterhans, 2008; Nowak, 1999)

Home Range

There is little available information on home range in mutable sun squirrels.

Communication and Perception

Mutable sun squirrels have a variety of vocalizations for communication. An alarm bark is used when trying to alert others to danger. A defensive growl is used to send a message to another to back off or beware. When making contact with other squirrels or family members, a bird-like sound is made. (Nowak, 1999)

Food Habits

Mutable sun squirrels are omnivorous. Their diet includes seeds, nuts, Kigelia fruits, and ivy leaves. When available, they also eat insects and bird eggs and, possibly, young vertebrates. (Nowak, 1999; Thorington, et al., 2012)

  • Animal Foods
  • eggs
  • insects
  • Plant Foods
  • seeds, grains, and nuts
  • fruit

Predation

Mutable sun squirrels are preyed upon by many, larger carnivorous species, including birds of prey and mammals. Genets, palm civets, and snakes have been noted as predators of other Heliosciurus species. When alarmed or surprised, they run to the opposite side of a tree, climb to a branch, and lay flat to avoid being seen. They also run to the tops of trees and sound an alarm call to alert others around them. Their coloration allows them to blend in with their surroundings. (Nowak, 1999)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

There is little available information on the roles mutable sun squirrels play in their ecosystems. However, as predators of seeds and fruits, they may influence the recruitment of tree and shrub species in the areas they inhabit.

Economic Importance for Humans: Positive

There is little available information on the benefits mutable sun squirrels provide to humans.

Economic Importance for Humans: Negative

Mutable sun squirrels are not thought to adversely affect humans.

Conservation Status

Mutable sun squirrels are listed as a species of least concern on the IUCN Red List. They do not suffer from loss of habitat by deforestation to make way for farmland. (Grubb and Kerbis Peterhans, 2008)

Contributors

Britney Frei (author), University of Wisconsin - Stevens Point, Christopher Yahnke (editor), University of Wisconsin-Stevens Point, Tanya Dewey (editor), University of Michigan-Ann Arbor, Shaina Stewart (editor), University of Wisconsin - Stevens Point.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

acoustic

uses sound to communicate

arboreal

Referring to an animal that lives in trees; tree-climbing.

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

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

diurnal
  1. active during the day, 2. lasting for one day.
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.

female parental care

parental care is carried out by females

forest

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

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

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.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

scrub forest

scrub forests develop in areas that experience dry seasons.

sedentary

remains in the same area

sexual

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

social

associates with others of its species; forms social groups.

solitary

lives alone

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Grubb, P., J. Kerbis Peterhans. 2008. "Heliosciurus mutabilis" (On-line). Accessed August 16, 2013 at http://www.iucnredlist.org/details/full/9831/0.

Grubb, P. 1982. "Systematics of sun-squirrels (Heliosciurus) in eastern Africa" (On-line). Bonner Zoologische Beiträge. Accessed August 07, 2013 at http://zfmk.de/BZB/1982/1982%20Grubb%20P.%20p191%20orginal.pdf.

Nowak, R. 1999. Walker's Mammals of the World. United States of America: The Johns Hopkins University Press. Accessed August 17, 2013 at http://books.google.com/books?id=7W-DGRILSBoC&pg=PA1281&dq=Heliosciurus+gambianus&hl=en&sa=X&ei=jN4PUv_jE4OGyQHCyIEw&ved=0CC8Q6AEwAA#v=onepage&q=Heliosciurus%20gambianus&f=false.

Thorington, R., J. Koprowski, M. Steele, J. Whatton. 2012. Squirrels of the World. Baltimore: The Johns Hopkins University Press.

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