||The Mammals of Texas -
Spotted Ground Squirrel
Rodentia : Family Sciuridae : Spermophilus
Description. A small ground squirrel with
scattered, more or less squarish, light spots on back
(spots not in rows as in S. mexicana and
inconspicuous; tail about one-third of total length,
pinkish buff or cinnamon buff beneath; upperparts smoke
gray, light drab or fawn color, the white spots small and
obsolete, especially on shoulder; underparts white.
External measurements average: total length, 214 mm;
tail, 65 mm; hind foot, 32 mm. Weight, 100-125 g.
Distribution in Texas. Known from western
one-half of state (not on Edwards Plateau) and southward
on Rio Grande Plain.
Habits. Spotted ground squirrels
seem to prefer dry, sandy areas, but they are also found
in grassy parks, open pine forests, scattered brush, and
occasionally on rocky mesas. On Mustang Island, off the
coast of Texas, they live in the sand dunes and share
their runways through the sparse vegetation with kangaroo
rats, grasshopper mice, and other small rodents. Near Van
Horn, they are rather common in the sandhills covered
with yuccas and other desert shrubs, and in the southern
part of the Big Bend they occur in small numbers on
rather hard ground covered with creosote bushes. The
opening to their burrows is usually under bushes or
overhanging rocks. One excavated burrow had three
openings, was about 4 m long, descended no more than 50
cm, and terminated in a nest chamber. A burrow in the Big
Bend had an opening about 5 cm in diameter and was marked
by a slight mound.
These squirrels are extremely shy. One
can work in an area several days without seeing them.
They are most active in early morning and late afternoon
to avoid the midday heat. They seldom go far from their
burrows and retreat to them at the slightest sign of
danger. Their movements are rapid and interrupted by
abrupt stops, reminding one of a lizard. In running, the
body and tail are held close to the ground.
Hibernation probably is not complete in
these squirrels, especially in the southern part of their
range. Specimens have been taken in November, December,
January, and February in Texas.
Their food is largely green vegetation
and seeds. Specific items are cactus pulp, mesquite
beans, saltbush seeds, sandbur, sunflower, gourd, iris,
grasshoppers, and beetles.
Their breeding habits are not
well-known. Females captured in mid-June, at which time
half-grown young were common, contained five to seven
embryos. This indicates that two litters may be reared
yearly. Young, presumably about a month old, have been
observed above ground as early as April 28 and as late as
September 17, which would suggest that mating begins in
February and continues into mid-July. The gestation
period is not known, but is probably about 30 days. Six
young spotted ground squirrels reared in captivity were
found to weigh an average of 17 g at 34 days of age,
their eyes opened at 27-28 days, and they were weaned at
about 48 days.
Photo credit: R. D. Porter.