Cape Ground Squirrel
Encyclopedia
The Cape Ground Squirrel (Xerus inauris) is found in most of the drier parts of southern Africa
from South Africa
, through to Botswana
, and into Namibia
.
The name Cape Ground Squirrel is somewhat misleading as it actually has a much wider area of habitation. This common name may have been arrived at to distinguish it from a tree squirrel
(the Eastern Grey Squirrel) found around Cape Town
, which was imported from Europe
by Cecil John Rhodes
.
of the males are relatively large with a well-developed terminal baculum
and turns downwards at the apex. This species is notable for its enlarged testes which are around 20% of the length of the head and body. Molting occurs between August and September and between March and April, once per year.
s and grasslands with hard ground. They can also be found in scrub on the fringes of pans, on floodplains and in cultivated fields Ground squirrel are generally diurnal and do not hibernate. They are burrowing animals that dig and live in clusters of burrows averaging around 700 m square with 2-100 entrances. Burrow serve to protect the squirrel from extreme temperatures at the surface as well as predators. Nevertheless most of the day is spent foraging above ground. For thermoregulation, ground squirrels position their bush tail towards the sun while covering the head and back. Dust bathing is also done. Ground squirrels eat bulbs, fruits, grasses, herbs, insects and shrubs. They do not hoard food so foraging is a daily activity. The Cape ground squirrel gets its minimal water requirements from herbaceous vegetation and rarely drinks. A ground squirrel’s daily activities are made of around 70% feeding, 15-20% vigilant behavior and around 10% social interactions. The burrows of Cape ground squirrels are also used by meerkats and mongooses for the same reasons the squirrels use them. The association between Cape ground squirrels and meerkats appears to be mutually beneficial, whereas mongooses appear to be only commensals
of the squirrels. Predators of grounds squirrels include jackals, snakes and monitor lizards. Ground squirrels may be able to differentiate between scent cues from the feces of predators and non-predators. When threatened by predators, like snakes, ground squirrel will engage in mobbing behavior. Multiple squirrels will lung at the predator while placing their bush tails between themselves and the predator. When the predator lunges back, all the squirrels retreat. However, multiple mobbings are usually successful in driving anyway predators.
. After copulation, males will mastrubate which could function as a form of genital grooming and serve to reduce the chance of getting sexually transmitted infection
s. Estrous lasts three hours and occurs in one female of the group at a time. Gestation last ca. 48 days or 42-49 days. Lactation in females begins before they give birth. A lactating female move to a separate burrow to care for their young but she returns to the groups after weaning or losing her litter. There are 1-3 pups in a litter. They are born altrical, hairless and blind. The pups stay in the burrows for their first 45 days. By 35 days, the eyes are open. Seven days after emerging from the burrows, the pups can eat soild food. Lactation ends at around. 52 days. Males reach sexual maturity at eight months and leave their natal group while female mature at 10 months and remain in their natal group.
Southern Africa
Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...
from South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
, through to Botswana
Botswana
Botswana, officially the Republic of Botswana , is a landlocked country located in Southern Africa. The citizens are referred to as "Batswana" . Formerly the British protectorate of Bechuanaland, Botswana adopted its new name after becoming independent within the Commonwealth on 30 September 1966...
, and into Namibia
Namibia
Namibia, officially the Republic of Namibia , is a country in southern Africa whose western border is the Atlantic Ocean. It shares land borders with Angola and Zambia to the north, Botswana to the east and South Africa to the south and east. It gained independence from South Africa on 21 March...
.
The name Cape Ground Squirrel is somewhat misleading as it actually has a much wider area of habitation. This common name may have been arrived at to distinguish it from a tree squirrel
Tree squirrel
Tree squirrels include over a hundred species that are found on all continents except Antarctica, and are the members of the squirrel family most commonly referred to as "squirrels"...
(the Eastern Grey Squirrel) found around Cape Town
Cape Town
Cape Town is the second-most populous city in South Africa, and the provincial capital and primate city of the Western Cape. As the seat of the National Parliament, it is also the legislative capital of the country. It forms part of the City of Cape Town metropolitan municipality...
, which was imported from Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
by Cecil John Rhodes
Cecil John Rhodes
Cecil John Rhodes PC, DCL was an English-born South African businessman, mining magnate, and politician. He was the founder of the diamond company De Beers, which today markets 40% of the world's rough diamonds and at one time marketed 90%...
.
Description
The Cape ground squirrel has bristly and coarse short hair that covers its body and lacks underfur. The dorsal parts of the fur are cinnamon colored and have lighter and darker variation among individuals. The face, underbelly, sides of neck and ventral parts of limbs are white, while the skin is black. The ground squirrel has small exterior ear pinnae. The sides of its body each have a white stripe that extends from shoulder to thigh. The eyes have white lines around them. The tail is flattened dorsoventrally and is cover with white hair and 2 black bands at the base. The Cape ground is sexually dimorphic, although it is not pronounced. Males usually weigh 8-12% more than females, with the former weighing 423-649 g and the latter weighing 444-600 g. The Cape ground squirrel has a total length of 424-476 mm for males and 435-446 mm for females. The dental formula of the ground squirrel is . There are nine transverse intermolar palatal ridges that are interrupted at midline to form a furrow with two continuous ridges anterior to the molar. The females have two pairs of mammary: one being inguinal and the other being abdominal. The glans penisGlans penis
The glans penis is the sensitive bulbous structure at the distal end of the penis. The glans penis is anatomically homologous to the clitoral glans of the female...
of the males are relatively large with a well-developed terminal baculum
Baculum
The baculum is a bone found in the penis of most mammals. It is absent in humans, but present in other primates, such as the gorilla and chimpanzee.The bone aids in sexual intercourse.-Purpose:...
and turns downwards at the apex. This species is notable for its enlarged testes which are around 20% of the length of the head and body. Molting occurs between August and September and between March and April, once per year.
Distribution
The Cape ground squirrel lives thoughpot southern Africa; through Botswana, South Africa and Namibia. It is widely distributed throughout much of Namibia but is absent from coastal regions and the northwest. Ground squirrels inhabit central and southwestern Kalahari in Botswana. In South Africa, it can be found in the southwest region of Northwest province and ranges to the Free State east to 30 and in Lesotho. It can also be found in Northern Cape Province but is limited to the northeast. The southernmost limit of its range is Graaff Reinet district.Behavior and ecology
Cape ground squirrels live mainly in arid or semiarid areas. They prefer to live in open sandy veldVeld
The term Veld refers primarily to the wide open rural spaces of South Africa or southern Africa and in particular to certain flatter areas or districts covered in grass or low scrub...
s and grasslands with hard ground. They can also be found in scrub on the fringes of pans, on floodplains and in cultivated fields Ground squirrel are generally diurnal and do not hibernate. They are burrowing animals that dig and live in clusters of burrows averaging around 700 m square with 2-100 entrances. Burrow serve to protect the squirrel from extreme temperatures at the surface as well as predators. Nevertheless most of the day is spent foraging above ground. For thermoregulation, ground squirrels position their bush tail towards the sun while covering the head and back. Dust bathing is also done. Ground squirrels eat bulbs, fruits, grasses, herbs, insects and shrubs. They do not hoard food so foraging is a daily activity. The Cape ground squirrel gets its minimal water requirements from herbaceous vegetation and rarely drinks. A ground squirrel’s daily activities are made of around 70% feeding, 15-20% vigilant behavior and around 10% social interactions. The burrows of Cape ground squirrels are also used by meerkats and mongooses for the same reasons the squirrels use them. The association between Cape ground squirrels and meerkats appears to be mutually beneficial, whereas mongooses appear to be only commensals
Commensalism
In ecology, commensalism is a class of relationship between two organisms where one organism benefits but the other is neutral...
of the squirrels. Predators of grounds squirrels include jackals, snakes and monitor lizards. Ground squirrels may be able to differentiate between scent cues from the feces of predators and non-predators. When threatened by predators, like snakes, ground squirrel will engage in mobbing behavior. Multiple squirrels will lung at the predator while placing their bush tails between themselves and the predator. When the predator lunges back, all the squirrels retreat. However, multiple mobbings are usually successful in driving anyway predators.
Social behavior
Social groups of Cape ground squirrels usually consist of 2-3 adult females and up to nine sub-adults of either sex an well as the females’ dependant offspring. Groups that have more than three females fission into smaller groups. Adult males live separately from females and only join when the latter is an estrous. Males live in permanent, non-aggressive groups of unrelated individuals that can number up to 19. Within a male groups, 4-5 males may form temporary subgroups that change size and composition daily. Females groups live in separate burrow clusters. A female group’s home range is ca. 4 ha with core areas of around 0.25 ha. Home ranges can overlap however core areas are defended though agonistic behavior. Male group home ranges encompass those of several female group home ranges and average 12.1 ha. Within a female group, members share feeding and sleeping ranges. No dominance hierarchy exists between them. Male groups, by contrast, have distinct linear dominance hierarchies based on age and are maintained by displacements. Competition between males usually consists of nonviolent leaping displays that cause no injuries. In addition, males groups are not territorial like female groups are. There is frequent immigration and emigration of members of male groups. During estrous, a female will be approached, solicited and chased by males trying to mate with her. The most dominant males get the first matings. A female will allow multiple copulations with the original males as well as subsequent males. If a male has not yet mated with a female, he will disrupt the copulations she has with other males. However, mate guarding is rare.Communication
When perceiving something at a threat, ground squirrels will emit a whistle-like call as an alarm call. The alarm call comes in two forms; a short, shrill "bi-jo" which is the greater of the alarms and elicits the greater reactions from the others, and a medium-pitched "bi-joo" sound with is used for less imminent threats. During agonistic encounters, individuals emit deep, aggressive growls. Juvenile squirrels make play calls, nest-chirpings, and protest squeaks.Reproduction
Cape ground squirrel mate throughout the year but peaks in mating occur in dry winter months. Since females copulate with multiple males, the males' large testes are useful for sperm competitionSperm competition
Sperm competition is a term used to refer to the competitive process between spermatozoa of two different males to fertilize an egg of a lone female. Competition occurs whenever females engage in promiscuous mating to increase their chances in producing more viable offspring...
. After copulation, males will mastrubate which could function as a form of genital grooming and serve to reduce the chance of getting sexually transmitted infection
Sexually transmitted disease
Sexually transmitted disease , also known as a sexually transmitted infection or venereal disease , is an illness that has a significant probability of transmission between humans by means of human sexual behavior, including vaginal intercourse, oral sex, and anal sex...
s. Estrous lasts three hours and occurs in one female of the group at a time. Gestation last ca. 48 days or 42-49 days. Lactation in females begins before they give birth. A lactating female move to a separate burrow to care for their young but she returns to the groups after weaning or losing her litter. There are 1-3 pups in a litter. They are born altrical, hairless and blind. The pups stay in the burrows for their first 45 days. By 35 days, the eyes are open. Seven days after emerging from the burrows, the pups can eat soild food. Lactation ends at around. 52 days. Males reach sexual maturity at eight months and leave their natal group while female mature at 10 months and remain in their natal group.