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Home -> Kingdom Animalia -> Phylum Chordata -> Subphylum Vertebrata -> Class Mammalia -> Order Rodentia -> Suborder Sciuromorpha -> Family Sciuridae -> Subfamily Sciurinae -> Species Tamiasciurus hudsonicus

Tamiasciurus hudsonicus
red squirrel



2008/06/15 08:42:09.348 GMT-4

By Tanya Dewey

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Rodentia
Suborder: Sciuromorpha
Family: Sciuridae
Subfamily: Sciurinae
Genus: Tamiasciurus
Species: Tamiasciurus hudsonicus

Geographic Range

Red squirrels are native to the Nearctic region and have one of the widest distributions of all North American squirrels. They are found from Alaska continuously across Canada to the northeast United States and south through the Appalachian states. They also occur throughout the Rocky Mountains. (Ruff and Wilson, 1999)

Biogeographic Regions:
nearctic (native ).

Habitat

Red squirrels are found in a variety of forested habitats, including coniferous, deciduous, and mixed forests. They can be found in suburban settings where there are large stands of mature trees. (Ruff and Wilson, 1999)

These animals are found in the following types of habitat:
temperate ; terrestrial .

Terrestrial Biomes:
forest .

Other:
suburban .

Physical Description

Mass
140 to 250 g; avg. 194.50 g
(4.93 to 8.8 oz; avg. 6.85 oz)


Length
280 to 350 mm
(11.02 to 13.78 in)


Basal Metabolic Rate


Red squirrels have a total body length of from 280 to 350 mm, with the tail making up from 95 to 150 mm of that. Fur color is highly variable. Red squirrels in different part of their range can look quite different. Color changes between summer and winter as well. The fur on their back is usually brownish or olive-red in color. During the summer, a black stripe runs along their side, between the fur color of their back and their belly. The belly is white or cream color. The tail is often edged with white. There are white bands encircling their large, black eyes. The tail is not as thick or bushy as other North American tree squirrels. They are well adapted for climbing and running through the trees with compact, muscled bodies, strong claws, and powerful hind limbs. (Ruff and Wilson, 1999)

Some key physical features:
endothermic ; bilateral symmetry .

Reproduction

Breeding interval
Red squirrels can breed several times in the breeding season.

Breeding season
Breeding is from mid-January to mid-February.

Number of offspring
1 to 8

Gestation period
33 to 35 days

Birth Mass
7 g (average)
(0.25 oz)
[External Source: AnAge]


Time to weaning
7 to 8 weeks

Age at sexual or reproductive maturity (female)
1 years (average)

Age at sexual or reproductive maturity (male)
1 years (average)

In warmer climates there are two breeding seasons, in the late winter and mid-summer. In colder climates, there is only one which begins at the spring thaw, from mid-January to mid-February. She gives birth, after a 33 to 35 day pregnancy, in a lined den or tree hollow, to from 1 to 8 young. Litter size is typically 2 to 5. The young develop very quickly and are weaned 7 to 8 weeks after birth. At 40 days old they leave the nest. Juvenile mortality is high, with owls, hawks, and pine martens taking many individuals. About 25% survive to adulthood, which is achieved around one year after young are born. (Ruff and Wilson, 1999)

Key reproductive features:
iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous .

Females care for and nurse their young in the nest for 40 days. In the fall following their birth the young disperse from their mother's home range. (Ruff and Wilson, 1999)

Parental investment:
altricial ; pre-fertilization (provisioning, protecting: female); pre-hatching/birth (provisioning: female, protecting: female); pre-weaning/fledging (provisioning: female, protecting: female).

Lifespan/Longevity

Extreme lifespan (wild)
7 years (high)

Average lifespan (captivity)
9.80 years
[External Source: AnAge]


Red squirrels can live up to 7 years in the wild, though most will die before they are 1 year old. (Ruff and Wilson, 1999)

Behavior

Red squirrels are solitary, diurnal animals that are active throughout the year. Their peak activity times are at dawn and in the late afternoon. They den in old woodpecker holes, tree hollows, or any other small crevice near their home range. In the northern part of their range, red squirrels often spend the winter in a system of underground tunnels. Red squirrels often migrate if their local food supply runs low. During these migrations they will often cross water and are good swimmers. (Ruff and Wilson, 1999)

Home Range

Home ranges are usually 1 to 2.4 hectares in area. (Ruff and Wilson, 1999)

Key behaviors:
arboreal ; scansorial; diurnal ; motile ; sedentary ; solitary ; territorial .

Communication and Perception

Red squirrels have keen senses of smell, sight, and hearing. They are very vocal and loudly scold intruders in their home range. Vocalizations consist of rattles, screeches, growls, buzzes, and chirps. (Ruff and Wilson, 1999)

Communicates with:
visual ; tactile ; acoustic ; chemical .

Perception channels:
visual ; tactile ; acoustic ; chemical .

Food Habits

Red squirrels are not picky eaters. They consume seeds, fruit, nuts, bark, buds, shed antlers, reptiles, insects, tree sap, pine cones, fungi (including mushrooms that are poisonous to humans), eggs, young birds, mice, and young rabbits. However, red squirrels eat primary the seeds of conifer trees. They may eat up to 2/3 of the pine seed crop in an area each year. Red squirrels store many seeds and nuts underground, in piles, or under rocks for the winter. They are able to relocate these buried seeds 30 cm underground and 4 meters below snow with their tremendous sense of smell. Many seed stockpiles are not recovered, however, making red squirrels a key tree planter and seed disperser. (Ruff and Wilson, 1999)

Primary Diet:
omnivore .

Animal Foods:
birds; mammals; eggs; insects; terrestrial non-insect arthropods.

Plant Foods:
roots and tubers; wood, bark, or stems; seeds, grains, and nuts; fruit; flowers.

Other Foods:
fungus.

Foraging Behaviors:
stores or caches food .

Predation

Known predators

Red squirrels are quick and agile and can escape predators by taking refuge in thick vegetation or in the trees. Red squirrels are also fairly aggressive small animals and will defend themselves if cornered. (Ruff and Wilson, 1999)

Ecosystem Roles

Red squirrels can have a large impact on tree populations in two ways. They can severely limit the regrowth of conifer trees because they eat so many of their seeds. However, through their activities they also distribute the spores of beneficial fungi that help trees to acquire nutrients and grow and they accidentally plant the seeds of young trees, improving their chances of growing. Red squirrels are important prey animals for many small predators because of their abundance in the habitats in which they live. (Ruff and Wilson, 1999)

Key ways these animals impact their ecosystem:
disperses seeds.

Economic Importance for Humans: Negative

Red squirrels can severely damage young trees in plantations, and crops in storage. They may also gnaw on many household items and can become a nuisance if they nest in homes.

Ways that these animals might be a problem for humans:
crop pest; household pest.

Economic Importance for Humans: Positive

Red squirrels are beneficial because of their dispersal of tree seeds and the spores of fungi required by many trees for successful growth. About 1 to 3 million red squirrels are harvested annually for their fur in Canada, bringing in about $1 million. They are a major prey item for other economically important species such as martens, bobcats, and lynx. (Ruff and Wilson, 1999)

Ways that people benefit from these animals:
body parts are source of valuable material.

Conservation Status

IUCN Red List: [link]:
Lower Risk - Least Concern.

US Federal List: [link]:
Endangered; No special status.

CITES: [link]:
No special status.

State of Michigan List: [link]:
No special status.

Red squirrels are common and not currently threatened throughout most of their range. A subspecies, the Mt. Graham red squirrel in southeastern Arizona, has been reduced to 150 individuals and is listed as endangered. A new observatory complex, campgrounds, and continued logging threatens its last habitat. (Ruff and Wilson, 1999)

Contributors

Tanya Dewey (author), Animal Diversity Web, University of Michigan Museum of Zoology.

Eric J. Ellis (author), University of Michigan.

References

MacDonald, Dr. David. 1984. The Encyclopedia of Mammals. Equinox (Oxford), Ltd. Pgs. 613-620.

Nowak, Ronald M. [Editorial Consultant]. 1987. Wild Animals of North America. The National Geographic Society. Pg. 123.

Nowak, Ronald M. 1991. Walker's Mammals of the World, 5th ed. The Johns Hopkins University Press. Pgs. 586-589.

Parker, Sybil P. [Editor]. 1990. Grzimek's Encyclopedia of Mammals, Vol 3. Pgs. 92-93.

"Animal Life Histories Database" (On-line).

Ruff, S., D. Wilson. 1999. The Smithsonian Book of North American Mammals. Washington [D.C.]: Smithsonian Institution Press in association with the American Society of Mammalogists.

2008/06/15 08:42:11.030 GMT-4

To cite this page: Dewey, T. and E. Ellis. 2007. "Tamiasciurus hudsonicus" (On-line), Animal Diversity Web. Accessed July 04, 2008 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Tamiasciurus_hudsonicus.html.

Disclaimer: The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

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