Hyraxes (from Ancient Greek ὕραξ (húrax) 'shrewmouse'), also called dassies,[1][2] are small, thickset, herbivorous mammals in the orderHyracoidea. Hyraxes are well-furred, rotund animals with short tails. Typically, they measure between 30 and 70 cm (12 and 28 in) long and weigh between 2 and 5 kg (4 and 11 lb). They are superficially similar to pikas and marmots, but are more closely related to elephants and sea cows.
Hyraxes have a life span from 9 to 14 years. Five extant species are recognised: the rock hyrax (Procavia capensis) and the yellow-spotted rock hyrax (Heterohyrax brucei), which both live on rock outcrops, including cliffs in Ethiopia[3] and isolated granite outcrops called koppies in southern Africa;[4] the western tree hyrax (Dendrohyrax dorsalis), southern tree hyrax (D. arboreus), and eastern tree hyrax (D. validus).[5] Their distribution is limited to Africa, except for P. capensis, which is also found in the Middle East.
Hyraxes retain or have redeveloped a number of primitive mammalian characteristics; in particular, they have poorly developed internal temperature regulation,[6] for which they compensate by behavioural thermoregulation, such as huddling together and basking in the sun.
Unlike most other browsing and grazing animals, they do not use the incisors at the front of the jaw for slicing off leaves and grass; rather, they use the molar teeth at the side of the jaw. The two upper incisors are large and tusk-like, and grow continuously through life, similar to those of rodents. The four lower incisors are deeply grooved "comb teeth". A diastema occurs between the incisors and the cheek teeth. The dental formula for hyraxes is 1.0.4.32.0.4.3.
Although not ruminants, hyraxes have complex, multichambered stomachs that allow symbiotic bacteria to break down tough plant materials, but their overall ability to digest fibre is lower than that of the ungulates.[7] Their mandibular motions are similar to chewing cud,[8] but the hyrax is physically incapable of regurgitation[9][10] as in the even-toed ungulates and the merycism of some of the macropods. This behaviour is referred to in a passage in the Bible which describes hyraxes as "chewing the cud".[11] This chewing behaviour may be a form of agonistic behaviour when the animal feels threatened.[12]
The hyrax does not construct dens, as most rodents and rodent-like mammals do, but over the course of its lifetime rather seeks shelter in existing holes of great variety in size and configuration.[13]