page_title: Hyrax
section_title: Evolution
hierarchical_section_title: Hyrax / Evolution
caption_attribution_description: Italiano: Fossil of Pachyhyrax championi, an extinct mammal -- Took the photo at Natural History Museum, London
context_page_description: Hyraxes, also called dassies, are small, thickset, herbivorous mammals in the order Hyracoidea. Hyraxes are well-furred, rotund animals with short tails. Typically, they measure between 30 and 70 centimetres long and weigh between 2 and 5 kilograms. They are superficially similar to pikas and marmots, but are more closely related to elephants and manatees.
  Five extant species are recognised; the rock hyrax and the yellow-spotted rock hyrax, which both live on rock outcrops, including cliffs in Ethiopia and isolated granite outcrops called koppies in southern Africa, the western tree hyrax, southern tree hyrax, and eastern tree hyrax. Their distribution is limited to Africa, except for Procavia capensis, which is also found in the Middle East.
context_section_description: All modern hyraxes are members of the family Procaviidae (the only living family within Hyracoidea) and are found only in Africa and the Middle East. In the past, however, hyraxes were more diverse, and widespread. The order first appears in the fossil record at a site in the Middle East in the form of Dimaitherium, 37 million years ago. For many millions of years, hyraxes, proboscideans, and other afrotherian mammals were the primary terrestrial herbivores in Africa, just as odd-toed ungulates were in North America.
  Through the middle to late Eocene, many different species existed, the largest of them weighing the same as a small horse and the smallest the size of a mouse. During the Miocene, however, competition from the newly developed bovids, which were very efficient grazers and browsers, displaced the hyraxes into marginal niches. Nevertheless, the order remained widespread and diverse as late as the end of the Pliocene (about two million years ago) with representatives throughout most of Africa, Europe, and Asia.
  The descendants of the giant 'hyracoids' (common ancestors to the hyraxes, elephants, and sirenians) evolved in different ways. Some became smaller, and evolved to become the modern hyrax family. Others appear to have taken to the water (perhaps like the modern capybara), ultimately giving rise to the elephant family and perhaps also the sirenians. DNA evidence supports this hypothesis, and the small modern hyraxes share numerous features with elephants, such as toenails, excellent hearing, sensitive pads on their feet, small tusks, good memory, higher brain functions compared with other similar mammals, and the shape of some of their bones.
  Hyraxes are sometimes described as being the closest living relative of the elephant, although whether this is so is disputed. Recent morphological- and molecular-based classifications reveal the sirenians to be the closest living relatives of elephants. While hyraxes are closely related, they form a taxonomic outgroup to the assemblage of elephants, sirenians, and the extinct orders Embrithopoda and Desmostylia.
  The extinct meridiungulate family Archaeohyracidae, consisting of four genera of notoungulate mammals known from the Paleocene through the Oligocene of South America, is a group unrelated to the true hyraxes.
caption: Pachyhyrax championi, a large fossil hyrax from the Miocene of Rusinga, Kenya (Natural History Museum collection)
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