; cohort Ferungulata, superorder Paenungulata (or Mesaxonia))
An order of primitive ungulates, containing the single family Procaviidae, which are small, gregarious, herbivorous, terrestrial or arboreal mammals, superficially resembling rabbits and occupying similar niches. The hyrax has short ears and no tail. The fore limb has four digits and the hind limb three. The second digit of the hind limb has a long claw, used possibly for grooming or for climbing, the remaining digits have hoof-like nails. The gait is plantigrade. The single pair of upper incisors grow continually and are used for defence; the lower incisors are comb-like and are used in grooming. The intestine has chambers containing symbionts which digest cellulose. A variety of ancestors, some the size of small horses but others similar to modern forms, are encountered first in the lower Oligocene of N. Africa: they lived throughout the Tertiary, so modern hyraxes may be very similar to early small ungulates. There are about five species, in three genera: Procavia and Heterohyrax (rock hyraxes), and Dendrohyrax (tree hyrax). These are distributed throughout Africa, the Mediterranean region, and Arabia, some living in deserts, where they survive with very little water.
Subjects: Zoology and Animal Sciences.