California gray squirrel, Western gray squirrel
The western gray squirrel (Sciurus griseus ) is an arboreal rodent found along the western coast of the United States and Mexico. It is a tree squirrel.In some places, this species has also been known as the silver-gray squirrel, the California gray squirrel, the Oregon gray squirrel, the Columbian gray squirrel and the banner-tail. There are three geographical subspecies: Sciurus griseus griseus (central Washington to the western Sierra Nevada in central California); S. g. nigripes (from south of San Francisco Bay to San Luis Obispo County, California); and S. g. anthonyi (which ranges from San Luis Obispo to northern Baja California).
In some landscapes, the Western grey squirrel has lost habitat or experienced local extinction due to competition with other squirrel species and other pressures on their population.
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DiurnalDiurnal animals are active during the daytime, with a period of sleeping or other inactivity at night. The timing of activity by an animal depends ...
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GranivoreSeed predation, often referred to as granivory, is a type of plant-animal interaction in which granivores (seed predators) feed on the seeds of pla...
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FrugivoreA frugivore is an animal that thrives mostly on raw fruits or succulent fruit-like produce of plants such as roots, shoots, nuts, and seeds. Approx...
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InsectivoresAn insectivore is a carnivorous plant or animal that eats insects. An alternative term is entomophage, which also refers to the human practice of e...
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ArborealArboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some anima...
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AltricialAltricial animals are those species whose newly hatched or born young are relatively immobile. They lack hair or down, are not able to obtain food ...
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
Among animals, viviparity is the development of the embryo inside the body of the parent. The term 'viviparity' and its adjective form 'viviparous'...
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Generally solitaryGenerally solitary animals are those animals that spend their time separately but will gather at foraging areas or sleep in the same location or sh...
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Not a migrantAnimals that do not make seasonal movements and stay in their native home ranges all year round are called not migrants or residents.
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starts withWestern gray squirrel has a long, bushy and white-edged tail, which helps the animal balance while jumping from tree to tree. The limbs are considerably large. During the winter months, the prominent ears are usually colored in reddish-brown at the back. This rodent is actually the largest tree squirrel, native to Washington. The animal exhibits white under-parts and a salt-and-pepper to steel gray coloration of its back.
The range of this rodent extends across Pacific region of the western U.S. and northern Mexico, from northern Washington State to northern edges of Baja (California). Western grey squirrel typically inhabits woodlands and coniferous forests.
Western gray squirrel is a diurnal animal that is active during the daytime hours. This rodent spends a lot of its active time outside the nest, grooming, exploring the environment, foraging and resting. They usually combine exploring and foraging, whereas grooming takes 3 - 15 minutes, during which most of the time is spent on the head. Excess food is carried to the nest and buried within the individual's territory. When necessary, they can find stored food through the well-developed sense of smell. Each individual has its own territory of 0.5 - 7 hectares on average. Territories of female individuals are considerable smaller that these of males. These rodents don't hibernate. However, during the winter, they generally prefer remaining within their nests. Western gray squirrels are generally solitary and not territorial, except for estrus females. If the squirrel is threatened, it will give out barking sounds, accompanying it by tail-flicking and foot-stamping.
The diet of Western grey squirrel is characterized by its habitat. Populations in coniferous forests generally consume pinecone seeds, whereas those in hardwood forests eat nuts and acorns. Overall, these rodents favor berries, fungus, bark, sap as well as various insects.
Little is known about the mating system of Western gray squirrels. During the breeding period, mating individuals are known to bite and injure each other. Females display highly territorial behavior, engaging in fights and not tolerating one another in their territories. Breeding takes place once a year, from December to June. Gestation period lasts for 43 days, yielding 3 - 5 young per litter. The litter size typically depends on female's age: older females produce larger litters that younger ones. Newborn squirrels are born with closed eyes and ears and lack fur. Weaning takes about 3 months from 7 to 10 weeks old. The age of sexual maturity is 10 - 11 months old.
Since the early 1900s, when Eastern fox squirrels were introduced to Los Angeles area (Southern California), the local Western grey squirrel population has greatly suffered from this aggressive species. A great part of their population has been lost due to various diseases, road accidents as well as habitat degradation. The remaining population had to move into foothills and mountains because of urbanization, wild fires, excessive grazing and degradation of their forest habitat.
According to IUCN, the Western gray squirrel is uncommon but widely distributed and no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List.
