Springhares (Pedetidae)

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Springhares

(Pedetidae)

Class Mammalia

Order Rodentia

Suborder Sciurognathi

Family Pedetidae


Thumbnail description
Short front limbs, powerful hind legs; long vibrissae and eyelashes; front paws clawed for burrowing; bushy tail with a black tip; soft pelage on the body with pinkish brown to gray upperparts and brownish white underparts

Size
Head and body length 10.7–16.7 in (27.2–42.4 cm); tail length 1.8–18.4 in (30–46.8 cm); weight up to 8.8 lb (4 kg)

Number of genera, species
1 genus; 1 species

Habitat
Scrub and grassland

Conservation status
Vulnerable

Distribution
Angola, Botswana, Congo, Kenya, Mozambique, Namibia, South Africa, Tanzania, Zambia, and Zimbabwe

Evolution and systematics

The earliest known fossil of the Pedetidae was recorded from the early Miocene at Elizabethfeld in Namibia as Parapedetes namaquensis while a larger form of the modern springhare (Megapedetes) appeared later in the Miocene in East Africa. The fossil record may be traced via the early Pliocene site at Taung (P. gracilis) in the northwestern Cape Province of South Africa (where notable australopithecine remains were discovered) to Pleistocene deposits in Bulawayo, Zimbabwe (as Pedetes capensis).

Historical confusion about its taxonomic position, brought about in part by a lack of substantive palaeontlogical records, saw Pedetes placed initially in a subfamily of jerboas (Dipodidae). The family Pedetidae was positioned subsequently in the suborder Hystricomorpha before its reclassification within the suborder Sciurognathi. In the 1920s, the "Pedetini" were placed by some taxonomists in the family Anomaluridae considered by others to be part of the superfamily Anomaluroidea. The family Pedetidae has now been returned to the suborder Sciurognathi.

The taxonomy for this species is Yerbua capensis (Forster, 1778), Cape of Good Hope, South Africa.

Physical characteristics

Resembling a small kangaroo, the springhare has short, front limbs and powerful hind legs, the latter adapted to ricochetal locomotion. The front paws are clawed for use in digging. The hind feet have four long toes with straight claws. The heel, the sole of the foot, and the base of each toe are hairless. Its large eyes are set in a blunt, short head. It has long vibrissae and eyelashes and long, narrow ears, which are thinly haired at the tip and naked inside. A well-developed tragus keeps sand from the ears when the animal is burrowing

The bushy tail is roughly the same length as the head and body and is tawny in color. The distal third is dark brown to black and the tip is noticeably black

The pelage of the body is composed of long, straight hairs and is soft and well-furred. The hairs of the dorsal area are a pinkish brown to sand in color with black tips and dark gray roots. The ventrum is buffy-white with a similarly-colored strip running upwards in front of the thighs and on the

inside of the leg. The coloration of the springhare varies geographically: specimens from eastern South Africa are paler than those found further to the west.

Distribution

Springhares are widely distributed throughout southern and eastern Africa. Their range extends from South Africa

north to Angola and the southern Congo and northeast to Kenya but excludes eastern Zambia, southeastern and western Tanzania, and eastern and northern Kenya. They are present in areas of higher elevation (e.g., in Natal) but are absent from some coastal regions of South Africa, Tanzania, and Kenya and from the coastal fringes of the Namib Desert in Namibia. Some reports state that they occur neither in the east nor the northeast of Zimbabwe and in Mozambique only from the Sabi River southwards to about 25ºS but no further. Distribution patterns indicate that springhares avoid rocky ground. In Kenya, they are sometimes found on "black cotton" soil that has a high clay contents and becomes quite hard when dry.

Habitat

Springhares are found most commonly in arid and semiarid country with scant cover. Open, sandy areas are also favored, especially if these support light woodland. Heavily wooded areas are avoided. Pedetes is rarely documented in tall grass land but may enter these to feed on rhizomes. Heavily grazed areas are known to provide a useful food source because where the upper layers of grasses have been removed by larger ungulates, springhares will feed on the more succulent lower stems, often digging for roots when the aboveground plant growth has been consumed.

Behavior

The springhare is terrestrial and nocturnal, although individuals are occasionally observed during daylight hours. Although usually solitary, springhares may form male-female pairs. They are well equipped for burrowing and excavate one or more burrows with a diameter of 7.8–9.8 in (20–25 cm) up to 3 ft (0.9 m) below ground level, preferably in firm, sandy soil. They commence their emergence at dusk with a

powerful leap into the air to avoid the threat posed by potential predators waiting outside the entrance to the burrow.

Certain feeding areas may be favored and the springhare will return to these on a nightly basis, although established paths to the areas are not created. During feeding, Pedetes will move on all fours and will sit up, using its tail as a support, when consuming food. When proceeding at full speed, the species hops using only the rear legs in the same manner as kangaroos. Although a distance of 2.2 yd (2 m) (some sources suggest leaps of up to 9.8 yd [9 m]) may be covered in a single bound, springhares avoid moving at speed downhill due to their ricochetal gait.

Pedetes capensis has keen senses of hearing, smell, and vision and will run away at the least sign of danger due to its limited fighting abilities. When sleeping, Pedetes will sit on its

haunches with head and forelimbs buried between the thighs and the tail coiled around the body.

Although usually silent, the species may occasionally emit low grunts.

Feeding ecology and diet

The diet of the springhare incorporates stems and rhizomes of grasses (particularly fine leaf couch grasses), bulbs, and grain. In areas of cultivated land, maize (corn), barley, wheat, peanuts, and oats may be consumed. Beetles, locusts, and other insects may supplement the diet, when several miles per night need to be covered in the search for food. Feeding at some sites may damage commercial crops.

Reproductive biology

Young may be born at any time of the year, a possible reason for which may be the continuous availability of the rhizomes and shoots of couch grasses. The young are born in bare chambers in the burrows. One offspring is produced, although in very rare circumstances pregnant females may carry twin fetuses. Accurate data are lacking on the gestation period but this is believed to be in the region of two months. It has been suggested that the period between conceptions is on the order of 101 days, that the average interval between parturition and conception is 24 days, and that 3.6 is the mean number of pregnancies per year. At birth, the young weigh 9.8–10.6 oz (280–300 g), are well haired and open their eyes on the second day. Juveniles are suckled in the burrow by their mothers, who have two pairs of pectoral mammae, until they reach a weight of 2.75 lb (1,250 g) at six to seven weeks. When they emerge, they are weaned rapidly on a diet of grasses. Spermatogenesis occurs in males when they attain a body weight of 5.5 lb (2,500 g).

Conservation status

Although relatively abundant throughout its range, Pedetes capensis is classified as Vulnerable, largely, it is presumed, on account of the decline in the quality of its habitat and its exploitation by humans. Its natural predators are birds of prey and the larger carnivores. Humans hunt springhares both as pests and as food.

Significance to humans

Owing to the damage they can inflict on commercial crops by destroying both planted seeds and established root systems,

humans hunt springhares, while to indigenous people they represent a favorite source of food. It is estimated that the total number of springhares falling prey to hunters in a single year in Botswana was in excess of 2.5 million (of which 2.2 million were accounted for by pest hunters).

Springhares are known hosts of numerous parasites and, accordingly, play a role in the transmission to humans and cattle of bubonic plague, rickettsiasis, babesiasis, theileriosis, and toxicosis paralysis.


Resources

Books

De Graaff, G. The Rodents of Southern Africa. Durban and Pretoria: Butterworths, 1981.

Dieterlen, Fritz. "Family Pedetidae." In Mammal Species of the World. 2nd ed. Edited by Don E. Wilson and DeeAnn M. Reeder. Washington, DC: Smithsonian Institute Press, 1992.

International Union for Conservation of Nature and Natural Resources. Red List of Threatened Species. Gland and Cambridge: IUCN, 2002.

Kingdon, J. East African Mammals. Vol. 2. New York: Academic Press, 1974.

Smithers, Reay H. N. The Mammals of the Southern African Subregion. Pretoria: University of Pretoria, 1983.

Walker, Ernest P. Mammals of the World. Vol. 2. Baltimore: Johns Hopkins University Press, 1964.

Malcolm Pearch, PhD