Rock Hyrax

Rock Hyrax[1]
Conservation status
Least Concern (IUCN 3.1)[2]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Hyracoidea
Family:	Procaviidae
Genus:	Procavia Storr, 1780
Species:	P. capensis
Binomial name
Procavia capensis (Pallas, 1766)
Range map

The characteristic foot pads

The unusual incisors

The Rock Hyrax (Procavia capensis), or Cape Hyrax, is one of the four living species of the order Hyracoidea, and the only living species in the genus Procavia. Like all hyraxes, it is a medium-sized (~4kg) terrestrial mammal, superficially resembling a guinea pig with short ears and tail. The rock hyrax is found across Africa and the Middle East, in habitats with rock crevices in which to escape from predators. Hyraxes typically live in groups of 10–80 animals, and forage as a group. Their most striking behaviour is the use of sentries: one or more animals take up position on a vantage point and issue alarm calls on the approach of predators.

The rock hyrax has incomplete thermoregulation, and is most active in the morning and evening, although their activity pattern varies substantially with season and climate.

Over most of its range, the rock hyrax is not endangered, and in some areas is considered a minor pest. In Ethiopia, Israel and Jordan, they have been shown to be a reservoir of the leishmaniasis parasite.

Distribution

The rock hyrax occurs across sub-Saharan Africa, with the exception of the Congo basin and Madagascar. The distribution continues into northern Algeria, Libya and Egypt, and the Middle East, with populations in Israel, Jordan, Syria, the Arabian peninsula and eastern Turkey^[3]

Etymology

They are known as dassies in South Africa, and sometimes rock rabbits. . The Swahili names for them are pimbi, pelele and wibari, though the latter two names are nowadays reserved for the tree hyraxes. This species has many subspecies, many of which are also known as Rock or Cape Hyrax, although the former usually refers to African varieties. In Hebrew, the rock hyrax is called שפן סלע (shafan sela), meaning rock "shafan", where the meaning of shafan is obscure. ^[4]

Anatomy and physiology

The rock hyrax is squat and heavily built, adults reaching a length of 50cm and weighing around 4kg, with a slight sexual dimorphism; males being approximately 10% heavier than females. Their fur is thick and grey-brown color, although this varies strongly between different environments; from dark brown in wetter habitats, to light gray in desert living individuals.^[5] Hyrax size (as measured by skull length and humerus diameter) is correlated to precipitation, probably because of the effect on preferred hyrax forage.^[6]

Prominent in and apparently unique to hyraxes is the dorsal gland, which excretes a odour used for social communication and territorial marking. The gland is most clearly visible in dominant males.^[3]

The dorsal gland can be seen here as a patch of fur with a lighter colouration

The head of the rock hyrax is pointed, having a short neck with rounded ears. They have long black whiskers on their muzzles.^[7] The rock hyrax has a prominent pair of long, pointed tusk-like upper incisors which are reminiscent of the elephant, to which the hyrax is distantly related (see below). The forefeet are plantigrade, and the hindfeet semi-digitigrade. The soles of the feet have large, soft pads that are kept moist with sweat-like secretions. In males, the testes are permanently abdominal, another anatomical feature that hyraxes share with their relatives elephants and sirenians.^[3]

Thermoregulation in the rock hyrax has been subject to much research, as their body temperature varies with a diurnal rhythm. However, animals kept in constant environmental conditions also display such variation^[3] and this internal mechanism may be related to water balance regulation.^[8]

Ecology and behaviour

Basking in the sun

Hyraxes live in herds of up to 80 individuals. These herds are subdivided into smaller flocks consisting of a few families. These families consist of 3 to 7 related adult females, a dominant male, and several young. The dominant male defends and watches over the group. The male also marks its territory to avoid any altercations ^[9]. In Africa, hyraxes are preyed on leopards, egyptian cobras, puff adders, caracals, wild dogs, and eagles.^[10] In Israel, the rock hyrax is probably rarely predated by terrestrial predators, as their system of sentries and their reliable refuges provide considerable protection. Hyrax remains are almost absent from the droppings of wolves in the Judean Desert.^[11]

Feeding and foraging

Hyraxes feed on a wide variety of different plants, including both grasses ^[9] and broad leafed plants^[12]. They also have been reported to eat insects and grubs^[7]. The rock hyraxes forage for food up to about 50 metres from their refuge, usually feeding as a group and with one or more animals acting as sentries from a prominent lookout position. On the approach of danger, the sentries give an alarm call, and the animals quickly retreat to their refuge^[13]. They are able to go for many days without water due to the moisture they obtain through their food ^[14]. Despite their seemingly clumsy build, they are able to climb trees, and will readily enter residential gardens to feed on the leaves of citrus and other trees.

Reproduction

Rock hyrax give birth to two or three young after a 6-7 month gestation period. The young are well-developed at birth with fully-opened eyes and complete pelage. Young can ingest solid food after two weeks and are weaned at ten weeks. Young are sexually mature after 16 months, reach adult size at three years, and typically live about ten years^[3]. During seasonal changes, the weight of male reproduction organs (testis, seminal vesicles) changes due to sexual activity. Hyraxes were examined and found that between May and January, the males were inactive sexually. From February, there was a dramatic increase to the weight of these organs, and the males are able to copulate ^[15].

Social behaviour

The characteristic chewing/grunting behaviour

Rock hyraxes are very noisy and sociable ^[9]. Adults make use of at least 21 different vocal signals. The most familiar signal is a high trill, and is given in response to perceived danger^[7]. Rock hyrax calls are referred to as “songs.” Hyrax songs can provide important biological information such as size, age social status, body weight, condition, and hormonal state of the singer, as determined by measuring their song length, patterns, complexity, and frequency ^[16]. The rock hyrax also makes a loud grunting sound while moving its jaws as if chewing. This behaviour may be an aggressive reaction, and has been postulated as the origin of the misconception given in Leviticus 11:4-8 that the hyrax chews the cud.^[4]

The rock hyrax spends approximately 95% of its time resting^[3]. During this time, they can often be seen basking in the sun, which is thought to be an element of their complex thermoregulation.

Dispersal

Males have been categorised into four classes: territorial, peripheral, early, and late dispersers. The territorial males are the most dominant. Peripheral males are more solitary and sometimes take over a group when the dominant male is missing. Early peripheral males are juveniles that leave the birth site around 16 to 24 months of age. Late dispersers are also juvenile males, but they leave the birth site much later; around 30 or more months of age ^[17].

Other

Rock Hyraxes produce large quantities of hyraceum (sticky mass of dung and urine) that has been employed by people in the treatment of several medical disorders, including epilepsy and convulsions^[18].

Gallery

Foraging on Table Mountain, Cape Town	Demonstrating its rock climbing prowess.	Hyraxes will readily come into car parks and such areas adjacent to rural areas.	Basking on Table Mountain
A colony of hyrax in northern Israel

References

External links

Wikimedia Commons has media related to: Procavia capensis

Wikispecies has information related to: Procavia capensis

• Animal Diversity Website - Procavia capensis