Difference between revisions of "Hyrax" - New World Encyclopedia

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**** [[Rock hyrax]], ''Procavia capensis''
 
**** [[Rock hyrax]], ''Procavia capensis''
  
==See also==
 
{{Wikispecies|Procaviidae}}
 
{{Commons}}
 
* [[Altungulata]]
 
  
 
==References==
 
==References==
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{{Mammals}}
 
{{Mammals}}
 
{{Hyracoidea}}
 
{{Hyracoidea}}
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[[Category:Life sciences]]
 
[[Category:Life sciences]]

Revision as of 11:42, 29 January 2014

Not to be confused with Palatal expander.

Template:Automatic Taxobox Hyraxes (from the Greek ὕραξ "shrewmouse") 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 cm long and weigh between 2 and 5 kg. They are often mistaken for rodents, but are more closely related to elephants. Four species are recognised; the rock hyrax (Procavia capensis), the yellow-spotted rock hyrax (Heterohyrax brucei), the western tree hyrax (Dendrohyrax dorsalis) and the southern tree hyrax (Dendrohyrax arboreus). Their distribution is limited to Africa and the Middle East.

Characteristics

Hyraxes retain a number of primitive mammalian characteristics; in particular, they have poorly developed internal temperature regulation, which they compensate for by behavioural thermoregulation such as huddling and by 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 incisors are nonetheless large, and grow continuously through life, similar to rodents. There is a small diastema between the incisors and the cheek teeth. The dental formula for hyraxes is .

File:Hyraxchewing.ogv
A hyrax showing the characteristic chewing/grunting behaviour. Note the incisor tusks.

Although not ruminants, hyraxes have complex, multi-chambered stomachs that allow symbiotic bacteria to break down tough plant materials; their overall ability to digest fibre is similar to that of the ungulates.[1] Their mandibular motions (see video) have often been described as chewing cud,[2] although there is no evidence this behaviour is associated with the regurgitation of stomach contents[3] as in the even-toed ungulates and some of the macropods. This behaviour is referred to in a passage in the Bible (Leviticus 11:5) which describes hyraxes as chewing the cud. Some authors believe these chewing motions are a form of agonistic behaviour when the animal feels threatened, rather than being related to ingestion or mastication.[4]

Hyraxes inhabit rocky terrain across sub-Saharan Africa and the Middle East. Their feet have rubbery pads with numerous sweat glands, which help the animal maintain its grip when quickly moving up steep, rocky surfaces. Hyraxes have stumpy toes with hoof-like nails; there are four toes on each front foot and three on each back foot.[5]They also have efficient kidneys, retaining water so that they can better 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 16 to 17 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.[6]

Hyraxes have highly charged myoglobin, which has been inferred to reflect an aquatic ancestry.[7]

Similarities with elephants and sirenia

Hyraxes share several unusual characteristics with elephants and sirenia (manatees and dugongs) which have resulted in them all being placed in the taxon Paenungulata. Male hyraxes lack a scrotum and their testicles remain tucked up in their abdominal cavity next to the kidneys;[8][9] the same as elephants, manatees, and dugongs.[10] Female hyraxes have a pair of teats near their arm pits (axilla), as well as four teats in their groin (inguinal area); elephants have a pair of teats near their axillae, and dugongs and manatees have a pair of teats, one located close to each of the front flippers. The tusks of hyraxes develop from the incisor teeth as do the tusks of elephants; in most other mammals, tusks develop from the canines. Hyraxes, like elephants, have flattened nails on the tips of their digits, rather than curved, elongated claws which are usually seen on mammals (see[11]).

Historical accounts

Hyrax on Mount Kenya

The words "rabbit", "hare", or "coney" appear as terms for the hyrax in some English translations of the Bible. Early English translators had no knowledge of the hyrax (Hebrew שָּׁפָן shaphan),[12] and therefore no name for them. There are references to hyraxes in the Old Testament,[13] particularly in Leviticus 11, where they are described as lacking a split hoof and therefore being not kosher. It also incorrectly claims that the hyrax chews its cud. Some of the modern translations refer to them as rock badgers. Shaphan was also the name of a scribe of King Josiah.

Phoenician sailors visiting the coast of Spain circa 1100s B.C.E., mistaking the European rabbit for the rock hyrax from their native homeland, gave it the name i-shepan-ham. A theory exists that an adaptation and/or corruption of this name, used by the Romans, became Hispania, leading to Spanish España and English Spain, although this theory is somewhat controversial.[14]

Evolution

Tree hyrax in the Serengeti, Tanzania

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 at a site in the Middle East in the form of Dimaitherium, 37 million years ago.[15] For many millions of years, hyraxes were the primary terrestrial herbivore in Africa, just as odd-toed ungulates were in North America. Through the middle to late Eocene, there were many different species,[16] 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 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 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 to other similar mammals, and the shape of some of their bones.[17]

Hyraxes are sometimes described as being the closest living relative to the elephant,[18] 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 extinct orders such as Embrithopoda and Desmostylia.[19]

The extinct meridiungulate family Archaeohyracidae, consisting of four genera of notoungulate mammals known from the Paleocene through the Oligocene of South America[20] is a group unrelated to the true hyraxes.

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 (Rock hyrax)
        • Procavia antigua
        • Procavia transvaalensis

Extant species

In the 2000s, taxonomists reduced the number of recognized species of hyrax. In 1995, there were eleven or more recognized species; in 2013, only four are recognized. The animals which are no longer recognised as species are regarded as subspecies of the recognized four. There are over 50 recognized subspecies and species, many of which are considered highly endangered.[21]

  • 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
        • Rock hyrax, Procavia capensis


References
ISBN links support NWE through referral fees

  1. von Engelhardt et al. (1978) Production of methane in two non-ruminant herbivores. Comparative Biochemistry and Physiology Part A: Physiology 60 (3) 309-311
  2. Hendrichs, Hubert (1966). Vergleichende Untersuchung des Wiederkauverhaltens. Biologisches Zentralblatt 84 (6): 671–751.[verification needed]
  3. JB Sale - JE Afr. Nat. Hist. Soc, 1966
  4. http://www.zootorah.com/hyrax/hyrax.pdf
  5. http://www.awf.org/wildlife-conservation/hyrax
  6. Hoeck, Hendrik (1984). in Macdonald, D.: The Encyclopedia of Mammals. New York: Facts on File, 462–5. ISBN 0-87196-871-1. 
  7. One Protein Shows Elephants and Moles Had Aquatic Ancestors.
  8. Trevor Carnaby (1 January 2008). Beat about the Bush: Mammals. Jacana Media. ISBN 978-1-77009-240-2. 
  9. Septimus Sisson (1914). The anatomy of the domestic animals. W.B. Saunders Company. 
  10. Marshall Cavendish Corporation (1 September 2010). Mammal Anatomy: An Illustrated Guide. Marshall Cavendish. ISBN 978-0-7614-7882-9. 
  11. Picture of hyrax feet
  12. "Shaphan" in Strong's Concordance
  13. Lev 11:4-8; Deut 14:7; Ps 104:18; Prov 30:26
  14. Anthon, Charles. A System of Ancient and Mediæval Geography for the Use of Schools and Colleges pg.14
  15. Eugenie Barrow; Erik R. Seiffert; Elwyn L. Simons. (2010). A primitive hyracoid (Mammalia, Paenungulata) from the early Priabonian (Late Eocene) of Egypt. Journal of Systematic Palaeontology 8 (2): 213–244.
  16. Prothero, Donald R. (2006). After the Dinosaurs: The Age of Mammals. Bloomington, Indiana: Indiana University Press, 132. ISBN 978-0-253-34733-6. 
  17. "Hyrax: The Little Brother of the Elephant", Wildlife on One, BBC TV.
  18. Hirax song is a menu for mating. The Economist (15 January 2009). Retrieved 15 January 2009.
  19. Asher, R.J., Novacek, M.J., Geisher, J.H. (2003). Relationships of endemic African mammals and their fossil relatives based on morphological and molecular evidence. J. Mamm. Evol. 10: 131–194.
  20. McKenna, Malcolm C., and Bell, Susan K. 1997. Classification of Mammals Above the Species Level. Columbia University Press, New York, 631 pp. ISBN 0-231-11013-8
  21. Template:MSW3 Shoshani
Mammals
Monotremata (platypus, echidnas)

Marsupialia: | Paucituberculata (shrew opossums) | Didelphimorphia (opossums) | Microbiotheria | Notoryctemorphia (marsupial moles) | Dasyuromorphia (quolls and dunnarts) | Peramelemorphia (bilbies, bandicoots) | Diprotodontia (kangaroos and relatives)

Placentalia: Cingulata (armadillos) | Pilosa (anteaters, sloths) | Afrosoricida (tenrecs, golden moles) | Macroscelidea (elephant shrews) | Tubulidentata (aardvark) | Hyracoidea (hyraxes) | Proboscidea (elephants) | Sirenia (dugongs, manatees) | Soricomorpha (shrews, moles) | Erinaceomorpha (hedgehogs and relatives) Chiroptera (bats) | Pholidota (pangolins)| Carnivora | Perissodactyla (odd-toed ungulates) | Artiodactyla (even-toed ungulates) | Cetacea (whales, dolphins) | Rodentia (rodents) | Lagomorpha (rabbits and relatives) | Scandentia (treeshrews) | Dermoptera (colugos) | Primates |

Template:Hyracoidea

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