206 Xerus inaurissize: Female—TL 435–446 mm; T 196–207 mm; Mass 444–
600 g.
Male—TL 452–476 mm; T 194–211 mm; Mass 423–649 g.
Subtle sexual dimorphism exists, with males slightly
larger.
distribution: The South African ground squirrel is dis-
tributed widely in Namibia, Botswana, South Africa, and
Lesotho.
geographic variation: None.
conservation: IUCN status—least concern. Population
trend—stable.
habitat: The South African ground squirrel lives in open
terra i n w it h spa rse veget at ion (somet i mes dom i nated by t he
annual grass Schmidtia kalahariensis), such as karroid areas,
grasslands, overgrazed land, fl oodplains, or dry water-
courses. They prefer solid ground for making their burrows,
but are also found in the dunes of the Kalahari Desert.
natural history: This squirrel is a well-studied terres-
trial and diurnal species, renowned for its ability to tolerate
high temperatures and its sex-segregated social structure. It
exhibits several behaviors that enable it to continue actively
foraging when temperatures exceed 40°C. To decrease heat
absorption, the animal turns its back to the sun and raises
its dorsoventrally fl attened tail over its back like a parasol,
shielding its body from the sun. In an eff ort to minimize
contact with the hot soil, an animal stands on its tiptoes
while foraging. To further dissipate heat, the squirrel en-
gages in “hearth rugging,” in which it lies fl at in a shady area
with its limbs outstretched and its sparsely haired belly in
close contact with the cool earth. The animal also utilizes
“hearth rugging” to warm its body on cold mornings. These
behaviors can raise or lower a squirrel’s body temperature
by over 5°C, and they allow an individual to forage for twice
the amount of time. When temperatures become too ex-
treme, the squirrels return to their burrows, which are built
60–70 cm below the ground and provide an insulated cool
haven from the desolate heat above.
They spend their days feeding near burrow entrances.
Their diet changes with the season, shifting from grasses
and fruits during the wetter summer months to roots,
stems, seeds, fruits, and insects during the drier season. The
squirrels move over vast areas as they forage. For example,
burrows spread over an area of 200–400 m^2 and have 22–30
access holes. Burrow clusters of individual female groups
may be separated by several hundred meters, and males
maintain home ranges as large as 12.5 ha. Neither males nor
females are particularly aggressive, and colonies overlap
their foraging grounds by an average of 26 percent, with indi-
viduals from diff erent groups typically ignoring one another
while feeding within close proximity. The social structure
is segregated by sex and genetic relatedness into two kinds
of colonies: matrilineal kin groups of adult females and
mixed-sex groups of subadults that inhabit individual bur-
row clusters, and unrelated assemblies of males that rotate
among their burrows. Both female and male colonies are
composed of 6–12 animals. Only three reproductive females
may exist at one time in a single female group, forcing sub-
adult females to shift to another colony with fewer repro-
ductive females once they are old enough to mate. Males live
in vacant burrows except during mating, when they sleep
in female burrow clusters. Bachelor groups occupy wide
home ranges that span the home ranges of several female
groups. Small groups of these males move among the fe-
males searching for receptive animals.
Females become sexually mature at approximately 8
months of age when only one adult female is present in a
social group, and at 12 months when more than one repro-
ducing female is present. Females spontaneously ovulate
and remain in estrus for only four hours, mating with ap-
proximately four males during this time. The females give
birth to one to three young in a nest burrow that they dig
themselves, away from the group cluster. They remain there
to raise the litter until the kittens are developed enough to
emerge from the burrow, at which time they rejoin the so-
cial group. Lactation lasts an average of 52 days, and the
young are weaned within seven days of joining the largerXerus inauris. Photo courtesy Pitchaya and Rattapon Kaichid.