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Tamiasciurus douglasii

Tamiasciurus douglasii (*)

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Cladus: Synapsida
Cladus: Eupelycosauria
Cladus: Sphenacodontia
Cladus: Sphenacodontoidea
Cladus: Therapsida
Cladus: Theriodontia
Subordo: Cynodontia
Infraordo: Eucynodontia
Cladus: Probainognathia
Cladus: Prozostrodontia
Cladus: Mammaliaformes
Classis: Mammalia
Subclassis: Trechnotheria
Infraclassis: Zatheria
Supercohors: Theria
Cohors: Eutheria
Infraclassis: Placentalia
Cladus: Boreoeutheria
Superordo: Euarchontoglires
Ordo: Rodentia
Subordo: Sciuromorpha

Familia: Sciuridae
Subfamilia: Sciurinae
Tribus: Sciurini
Genus: Tamiasciurus
Species: Tamiasciurus douglasii
Subspecies: T. d. douglasii – T. d. mollipilosus

Tamiasciurus douglasii (Bachman, 1839)
Vernacular names
Deutsch: Douglas-Hörnchen
English: Douglas squirrel
français: écureuil de Douglas
polski: Wiewiórka czikari

Tamiasciurus douglasii in Mammal Species of the World.
Wilson, Don E. & Reeder, DeeAnn M. (Editors) 2005. Mammal Species of the World – A Taxonomic and Geographic Reference. Third edition. ISBN 0-8018-8221-4.


North American Mammals: Tamiasciurus douglasii [1]

The Douglas squirrel (Tamiasciurus douglasii) is a pine squirrel found in the Pacific Northwest of North America, including the northwestern coastal states of the United States as well as the southwestern coast of British Columbia in Canada, with an isolated subspecies in northern Baja California. It is sometimes known as the chickaree or pine squirrel, although these names are also used for the American red squirrel. Variant spellings of the common name are Douglas' squirrel and Douglas's squirrel. The Native Americans of Kings River called it the "Pillillooeet", in imitation of its characteristic alarm call.[4]


John Muir described the Douglas squirrel, Tamiasciurus douglasii, as "by far the most interesting and influential of the California Sciuridæ". Adults are about 33 cm in length (including its tail, which is about 13 cm long), and weigh between 150 and 300 grams. Their appearance varies according to the season. In the summer, they are greyish or almost greenish-brown on their backs, and pale orange on the chest and belly, while legs and feet appear brown. In the winter, the coat is browner and the underside is grayer; also, the ears appear even tuftier than they do in summer. Like many squirrels, Douglas squirrels have a white eye-ring.
Anacortes Community Forest Lands (Washington)

Mating can occur as early as February. Gestation is about four weeks, and the young (which are altricial) are weaned at about eight weeks of age. There may be up to six kits in a litter, though four is more usual. In the southern and lower parts of their range, they produce two litters each year.

Douglas squirrels live in coniferous forest habitats along the Pacific Coast, from the Sierra Nevada (mountains) of California, northwards to the southwestern coast of British Columbia. Tamiasciurus douglasii prefer old-growth forests or mature second-growth forests, and some authors regard them as dependent on its presence. Mearns's squirrel is a distinctive subspecies of the Douglas squirrel that instead inhabits xeric pine forests in a small portion of Baja California.[5]

Throughout most their range, Douglas squirrels essentially replace the American Red Squirrel, which inhabits the coniferous forests of the rest of North America, in these areas. The two species have very minimal overlap in the territory.

Douglas squirrels are territorial; in winter, each squirrel occupies a territory of about 10 000 square metres, but during the breeding season a mated pair will defend a single territory together. Douglas squirrels are active by day, throughout the year, often chattering noisily at intruders. On summer nights, they sleep in ball-shaped nests that they make in the trees, but in the winter they use holes in trees as nests. Groups of squirrels seen together during the summer are likely to be juveniles from a single litter.

Douglas squirrels mostly eat seeds of coniferous trees such as Douglas fir (Pseudotsuga menziesii), Sitka spruce (Picea sitchensis) and shore pine (Pinus contorta). They also eat the fleshy scales of green giant sequoia cones, as well as acorns, berries, mushrooms, the eggs of birds such as yellow warblers, and some fruit including strawberries and plums. Douglas squirrels are larder hoarders,[6] storing their food in a single location or 'larder' called a midden. As the squirrel peels the scales of cones to get at the seeds, the discarded scales accumulate into piles that can grow to several meters across as the same site is used by generations of squirrels.

Their predators include American martens, Bobcats, domestic cats, northern goshawks, and owls; although they quickly acclimatize to human presence, humans can be a threat to them, through robbing of their cone caches to find seeds for tree cultivation and through the destruction of old-growth forest. However, the squirrels' numbers appear to be unaffected by commercial thinning of forests.[7]
Pacific silver fir cone debris from Douglas squirrels feeding, North Cascades National Park
Tamiasciurus douglasii alarm call
Alarm call of the Douglas squirrel (Tamiasciurus douglasii)
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Linzey, A. V. & Hammerson, G. (2008). "Tamiasciurus douglasii". IUCN Red List of Threatened Species. 2008. Retrieved 8 January 2009.
Bachman, J. (1839) Archived January 7, 2009, at the Wayback Machine. Description of several new Species of American quadrupeds. Journal of the Academy of Natural Sciences of Philadelphia, 8, 57-74.
Thorington, R.W. Jr.; Hoffmann, R.S. (2005). "Family Sciuridae". In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: a taxonomic and geographic reference (3rd ed.). The Johns Hopkins University Press. pp. 754–818. ISBN 0-8018-8221-4. OCLC 26158608.
Muir, John (1989). "The Douglas Squirrel". The Mountains of California. The Sierra Club. p. 173. ISBN 0-87156-663-X.
Hope, Andrew G.; Malaney, Jason L.; Bell, Kayce C.; Salazar-Miralles, Fernando; Chavez, Andreas S.; Barber, Brian R.; Cook, Joseph A. (2016-07-01). "Revision of widespread red squirrels (genus: Tamiasciurus) highlights the complexity of speciation within North American forests". Molecular Phylogenetics and Evolution. 100: 170–182. doi:10.1016/j.ympev.2016.04.014. ISSN 1055-7903. PMID 27083861.
"Gray squirrels and scatter hoarding". 24 September 2013. Retrieved 2015-11-20.
Ransome, D. B., & Sullivan, T. P. (2002). Short-term population dynamics of Glaucomys sabrinus and Tamiasciurus douglasii in commercially thinned and unthinned stands of coastal coniferous forest. Canadian Journal of Forest Research, 32, 2043-2050.

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