Spermophilus beecheyi
California ground squirrel

Spermophilus beecheyi is found throughout most of California, most of Western Oregon and portions of Western Nevada. This species also occurs in portions of southwestern Washington, and Baja California. (MacClintock, 1970; Whitaker and Jr., 1980)

Spermophilus beecheyi has successfully exploited many habitat types. California ground squirrels are terrestrial, and semifossorial, requiring habitats with some loose soil where they can excavate an appropriate burrow.

You may find them colonizing fields, pastures, grasslands and in open areas such as oak woodlands. The only habitat they do not use is deserts. You may find them down in valleys and up on rocky outcrops in the mountains, to an elevation of 2,200 m. They can be found in urban, suburban and agricultural areas. By and large this species is widely distributed within its range. (Evans and Holdenried, 1943; MacClintock, 1970; Whitaker and Jr., 1980)

California ground squirrels have mottled fur, with gray, light and dark brown, and white present in their pelage. They typically have a darker mantle. The shoulders, neck and sides of this species are a lighter gray. The bushy tail is a combination of the colors that appear on the back. The underside is a lighter combination of light brown, gray and white. California ground squirrels have a white ring around each eye.

The body length can range from 330 to 508 mm and tail length from 127-229 mm. These animals range in weight from 280 to 738 g. The ears are > 10 mm and < 25.4 mm. The dental formula is 1/1 : 0/0 : 2/1 : 3/3 = 22. (Alden et al., 1998; Ingles, 1947; Linsdale, 1946; MacClintock, 1970; Whitaker and Jr., 1980)

The lifespan of a California ground squirrel can be up to 6 years in the wild. They have lived as long as 10 years in captivity. (MacClintock, 1970)

California ground squirrels live in burrow systems that can house many generations, forming a sort of colony. Each individual has an entrance of their own. They tend to stay within 150 yards of their burrow system and retreat, usually only to their entrance of that burrow system. They frequently spend time sunning themselves. Depending on the climate, they may hibernate, or aestivate to escape undesirable temperatures. Males are more aggressive than females and sometimes appear territorial. (Alden et al., 1998; Evans and Holdenried, 1943; Linsdale, 1946; MacClintock, 1970; Whitaker and Jr., 1980)

California ground squirrels use a variety of sounds, tail signals and scent production as means of communication. For example, glandular folds anterior to the tail region are used for individual identification. When finding a mate or mates, females may approach or males may approach, but scent cues are important in identifying reproductive condition. (Evans and Holdenried, 1943; Linsdale, 1946)

California ground squirrels use cheek pouches while they are foraging to collect more food than would otherwise be possible in one sitting. They are also known to cache or store food. They exploit a variety of food sources, which probably contributes to their success as a species.

The diet of these animals, as their genus name would suggest, is primarily seed-based. California ground squirrels consume seeds, barley, oats, and acorns (Quercus): valley oak, blue oak, coast oak). They also eat fruits, like gooseberries and pears, and quail (Callipepla) eggs. They include insects in their diets when they are available, and have been known to eat grasshoppers, crickets, beetles and caterpillars. They also eat roots, bulbs, and fungi, such as mushrooms. (Linsdale, 1946; MacClintock, 1970; Whitaker and Jr., 1980)

These ground squirrels are highly vulnerable to predation due to their diurnal habits, open habitat, and the concentrations of conspecifics found in any particular colony. They are known to be preyed upon by red-tailed hawks, golden eagles, coyotes, foxes, badgers, weasels, house cats, dogs, and wild cats such as bobcats and pumas. In addition, large snakes may prey upon them.

Spermophilus beecheyi individuals probably avoid predation mainly through the use of burrow systems and vigilance. They are also cryptically colored. Also, they have skin glands on their back, just posterior to the shoulders, which secrete an odorous oil which could deter predators. (Alden et al., 1998; Linsdale, 1946)

Due to their diet, California ground squirrels could play a role in regulating some insect populations. They may aid in seed dispersal when a cache is forgotten. they help to aerate the soil through their excavation of burrows, and create habitat for many other animals, such as other rodents and snakes, which occupy empty burrows. (Linsdale, 1946)

This species may threaten agricultural crops, such as grain fields and orchards, through their foraging activities. They are potential carriers of diseases, such as tularemia, bubonic plague, and sylvatic plague. The two latter diseases are from fleas the squirrels carry. (Alden et al., 1998; Boellstorff et al., 1994; MacClintock, 1970)

There are no special conservation practices currently for S. beecheyi. Some control of their numbers has been attempted, costing several hundred thousand dollars. These are generally targeted responses to crop damage or disease outbreaks. (Boellstorff et al., 1994; MacClintock, 1970)

Spermophilus beecheyi was named for Frederick William Beechey, who spent time exploring Northern California from 1826-1828. This species used to be known as Otospermophilus beecheyi.