Ground Squirrel, Spermophilus
This little guy showed no fear in November while collecting his (or her) season's cache of Valley oak acorns from the oak he lives under. He's got a big job ahead of him because a single mature Valley oak can produce a ton of acorns in a good year.
You may recognize this location... it's the hole under the first oak tree as you enter the Conference Room near the end of the Grapevine Trail. That's where grapevines cascading from four mature Valley oaks form a large 'room'. It's also a great location to take a close look at the soil under oaks. It's a fun little study so go ahead and play in the dirt!
Description: Gray, light brown and dusky fur are mixed to give the California Ground Squirrel's upperparts a mottled appearance. A band of slightly darker fur, flecked with light gray, extends from the head over the middle of the back. Gray fur forms a cape over the sides of the head and shoulders. This gray cape may have a protective function, breaking up the animal's body outline and making it more difficult for a predator to spot. Light buff or grayish yellow fur covers the undersides.
Whitish fur rings the eyes and perhaps protects the squirrel's eyes from too intense sunlight. Black fur edges the outer rims of the ears. The tail, five to seven inches long and more than half the length of the head and body, is covered with mixed yellowish gray and black hairs and is lighter on the underside. Generally, California Ground Squirrels measure between sixteen and nineteen inches total length.
Distribution: From central Washington through western Oregon, California and into the northern part of Baja California, this squirrel is found in plains, small meadows, tree-covered hillsides, rocky outcrops and granite taluses. The northern extent of its range was once bounded by the Columbia River, but the California Ground Squirrel has crossed the river into south-central Washington.
Habits: California Ground Squirrels live in burrows. Hillsides or low earth banks are preferred sites because the burrows can be excavated horizontally, although many burrows are dug down vertically several feet to assure protection. Burrows, which are about four or five inches in diameter, may vary in length from five feet to more than thirty-five feet and may be used by many generations of ground squirrels. Some burrows house single squirrel occupants, while others may be colonial homes for several squirrels. Short burrows many have a single opening, but longer branched burrows often have two or more openings. In studying California Ground Squirrels, one group of scientists found a squirrel home with six females and five males which consisted of tunnels totaling 741 feet in length and had thrity-three openings. The deepest tunnel was twenty-eight feet below ground. Although most tunnel excavation work is done in the spring, digging and burrow improvement is a continuing process.
During the breeding season, from about February to April, and during the summer months, California Ground Squirrels are above ground for long periods each day. They often spend their time feeding (they eat a variety of seeds, fruits, acorns, roots, mushrooms, and even insects such as grasshoppers, crickets, and caterpillars), sunning, dust-bathing, and grooming. In one of their favorite sun bathing positions the squirrel lies with its belly on the ground, elbows on the ground with forearms extended and head raised. They also like to sit straight up, motionless, with their arms hanging down across their chest and their paws resting one upon the other. From this position they love to look about. In fact, their vision is thought to be about equivalent to a human's.
California Ground Squirrels are ever vigilent and ready to sound an alarm if danger is perceived. If frightened, a squirrel often makes long leaps and emits a sharp, metallic alarm cry several times in rapid succession. The squirrel may pause near its burrow and clink at intervals, or it may drop down into its tunnel system.
Generally, ground squirrels spend most of their life within a fairly small area. In fact, most of their time is spent within about 100 feet of their burrow and rarely does a ground squirrel go beyond a 150-yard radius of its burrow.
California Ground Squirrels hibernate for several months of the year. How long they hibernate depends on where they live. In some areas, adult squirrels may spend as much as eight months dormant in their burrows. Sometime in the fall or eary winter the squirrels will settle in for the winter. It is interesting that the males are the first to begin hiberation. Females and young squirrels may not begin hibernation for over a month later. California Ground Squirrels go into "true hibernation," that is, unlike a bear which merely enjoys a long period of sleep, the ground squirrel goes into what might be thought of as a state of near suspended animation. Their heart rate slows down to as little as only a tenth of its normal heart rate and their respiration may slow down to the point where they only take a breath every couple of minutes. Even in this state, they wake up every four to five days for short periods. During these times they eat food they stored away in special chambers during the summer months and they use special "bathroom" chambers before climbing back into their underground nests. The males are the first to emerge from hibernation, usually in the early spring.
The breeding season, from February to April, is a busy time for California Ground Squirrels. Mating chases are common, with males chasing females until she is ready to accpet one. Females may mate with more than one male and often mate more than one time. After about a month-long gestation period, a mother squirrel may give birth from three to as many as fifteen babies, with from five to six being an average number. The babies remain underground with the mother. Their eyes open at about five weeks and by about the eighth week, they are ready to come out of the burrow for the first time. At first the youngesters will play and feed very near the burrow entrance under the mother's close and attentive supervision.
California Ground Squirrels may live as long as six years, but three or four years is probably their average life span in the wild. Captive ground squirrels have lived for ten years.