Hyrax

style="background:#Template:Taxobox colour;"|Hyraxes Fossil range: Early Eocene - Recent
Heterohyrax brucei Heterohyrax brucei
style="background:#Template:Taxobox colour;" | Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Infraclass: Eutheria Superorder: Afrotheria Order: Hyracoidea Huxley, 1869 Family: Procaviidae Thomas, 1892
Genera
Procavia Heterohyrax Dendrohyrax

A hyrax (from Greek Template:Polytonic 'shrewmouse'; Afrikaans: klipdassie, from Dutch: klipdas 'rockbadger') is any of four species of fairly small, thickset, herbivorous mammals in the order Hyracoidea. They live in Africa and the Middle East.

Hyraxes are well-furred rotund creatures with a mere stump for a tail. They are about the size of a Corgi; most measure between about 30 and 70 cm long and weigh between 2 and 5 kg. From a distance, a hyrax could be mistaken for a very well-fed rabbit or guinea pig.

Characteristics

File:Tree-hyrax.jpg

Tree Hyrax in the Serengeti, Tanzania

Hyraxes retain a number of early mammal characteristics; in particular they have poorly developed internal temperature regulation (which they deal with by huddling together for warmth, and by basking in the sun like reptiles). Unlike other browsing and grazing animals, they do not use the incisors at the front of the jaw for slicing off leaves and grass, and use the molar teeth at the side of the jaw instead. The incisors are nonetheless large, and grow continuously through life, in a similar manner to those of rodents. There is a short diastema between the incisors and the cheek teeth. The dental formula for hyraxes is:Template:Dentition2

Unlike the even-toed ungulates and some of the macropods, hyraxes do not chew cud to help extract nutrients from coarse, low-grade leaves and grasses. They do, however, have complex, multi-chambered stomachs which allow symbiotic bacteria to break down tough plant materials, and their overall ability to digest fibre is similar to that of the ungulates.

Hyraxes inhabit rocky terrain across sub-Saharan Africa. Their feet have rubbery pads with numerous sweat glands, which help the animal maintain its grip when moving fast up steep rocky surfaces. They also have efficient kidneys, retaining water so that they can survive in arid environments.

Female hyraxes give birth to up to four young after a gestation period of between seven and eight months, depending on the species. The young are weaned at one to five months of age, and reach sexual maturity at sixteen to seventeen months.

Hyraxes live in small family groups, dominated by a single male who aggressively defends the territory from rivals. Where there is abundant living space, the male may dominate multiple groups of females, each with their own range. The remaining males live solitary lives, often on the periphery of areas controlled by larger males, and mate only with younger females .

Historical accounts

File:Klipdas.jpg

Hyrax on Mount Kenya.

Early Phoenician navigators mistook the rabbits of the Iberian Peninsula for hyraxes (Hebrew Shaphan); hence they named it I-Shapan-im, meaning "land of the hyraxes", which possibly became the Latin word "Hispania", the root of Spain's modern Spanish name España and the English name Spain.

The word "rabbit, or "hare" was used instead of "hyrax" many times in some earlier English Bible translations. European translators of those times had no knowledge of the hyrax (Hebrew שָּׁפָן Shaphan), and therefore no name for them. There are references to hyraxes in the Old Testament which describe hyraxes and rabbits as cud-chewing animals, but the Hebrew phrase means literally, "raising up what has been swallowed." and they are not true cud chewers in the modern sense of the term, but rather coprophages. After eating, they ferment and partially digest their food; their cecum plays a similar role in this process to a cow's rumen. After passing this partially-digested food, they re-ingest it and complete the digestive process. Once digestion is complete, they pass feces of a different texture which they do not re-ingest.

Evolution

Hyraxes are sometimes described as being the closest living relative to the elephant. This is because they may share an ancestor in the distant past when hyraxes were larger and more diverse. However, the details of their relationship remain open to debate.

All modern hyraxes are members of the family Procaviidae (the only living family within the 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 over 40 million years ago, and for many millions of years hyraxes were the primary terrestrial herbivore in Africa, just as odd-toed ungulates were in the Americas. There were many different species, the largest of them about the weight of a small horse, the smallest the size of a mouse. During the Miocene, however, competition from the newly-developed bovids—very efficient grazers and browsers—pushed the hyraxes out of the prime territory and into marginal niches. Nevertheless, the order remained widespread, diverse and successful 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 evolved in different ways. Some became smaller, and gave rise to the modern hyrax family. Others appear to have taken to the water (perhaps like the modern capybara), and ultimately gave rise to the elephant family, and perhaps also the Sirenians (dugongs and manatees). 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, high brain functions compared to other similar mammals, and the shape of some of their bones.

Not all scientists support the proposal that hyraxes are the closest living relative of the elephant. Recent morphological and molecular based classifications reveal the Sirenians to be the closest living relatives of elephants, while hyraxes are closely related but form an outgroup to the assemblage of elephants, sirenians, and extinct orders like Embrithopoda and Desmostylia..

List of extinct species

• Pliohyracidae
  • Geniohyinae
    • Seggeurius
    • Geniohyus
  • Saghatheriinae
    • Microhyrax
    • Meroehyrax
    • Selenohyrax
    • Bunohyrax
    • Pachyhyrax
    • Megalohyrax
    • Saghatherium
    • Thyrohyrax
  • Titanohyracinae
    • Antilohyrax
    • Titanohyrax
  • Pliohyracinae
    • Sogdohyrax
    • Kvabebihyrax
    • Prohyrax
    • Parapliohyrax
    • Pliohyrax
    • Postschizotherium
• Procaviidae
  • Procaviinae
    • Gigantohyrax
    • Procavia (Cape Hyrax)
      • Procavia antigua
      • Procavia transvaalensis

Living species

Scientists have recently reduced the number of distinct species of hyrax recognized. As recently as 1995 there were eleven or more recognized species; only four are recognized today. The remaining species are regarded as subspecies of the remaining four. There are over 50 recognized subspecies and species, many of which are considered highly endangered.

• ORDER HYRACOIDEA
  • Family Procaviidae
    • Genus Dendrohyrax
      • Southern Tree Hyrax, Dendrohyrax arboreus
      • Western Tree Hyrax, Dendrohyrax dorsalis
    • Genus Heterohyrax
      • Yellow-spotted Rock Hyrax, Heterohyrax brucei
    • Genus Procavia
      • Cape Hyrax, Procavia capensis

External links

• A BBC Science and Nature article on Hyrax
• A reference to Hyrax on a website about elephants (includes video of Procavia capensis- video link dead-many links broken)