Sciuridae, Squirrels
Brownish, with 13 alternating brown and whitish longitudinal lines (sometimes partially broken into spots) on back and sides. Rows of whitish spots within dark lines.
Similar Species Spotted Ground Squirrel has scattered spots, and Mexican Ground Squirrel has 9 rows of squarish spots; neither has lines. However, Mexican Ground Squirrel may be difficult to distinguish; the two species occasionally hybridize when they have contact.
Mates in April; 1 litter per year of 10 young born in May, after gestation of 27 days.
Originally shortgrass prairies; now along roadsides, in yards, cemeteries, golf courses, and wherever grass is kept mowed.
Much of c North America, from se Alberta and s Manitoba south to n New Mexico, n and se Texas, and east through Minnesota and Missouri to Michigan and Ohio.
Strictly diurnal, this ground squirrel is especially active on warm days. A solitary or only somewhat colonial hibernator, it often occurs in aggregations in suitable habitats. In late summer, it puts on a heavy layer of fat and stores some food in its burrow. It enters its nest in October (some adults retire much earlier), rolls into a stiff ball, and decreases its respiration from 100 to 200 breaths per minute to one breath about every five minutes. It emerges in March or early April. The burrow may be 15 to 20 feet long, with several side passages. Most of the burrow is within 1 to 2 feet (about half a meter) of the surface, with only the hibernation nest in a special deeper section. Shorter burrows are dug as hiding places. The Thirteen-lined Ground Squirrel's home range is 2 to 3 acres . Grass and weed seeds, caterpillars, and grasshoppers, are its dietary staples, but it sometimes also eats bird flesh and even mice and shrews. This squirrel sometimes damages gardens by digging burrows and eating vegetables, but also devours weed seeds and harmful insects. It often stands upright to survey its domain, diving down into its burrow when it senses danger, then sometimes poking out its nose and giving a bird-like trill. It has a maximum running speed of 8 mph (13 km/h), and reverses direction if chased. Great numbers of these squirrels are killed by automobiles.