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- This article refers to the sheep genus. For the species commonly referred to simply as "sheep", see Domestic sheep.
A sheep is an individual of any of the five or more mammal species that comprise the genus Ovis, part of the goat-antelope subfamily. Sheep are bovids (members of the family Bovidae) and ruminants, meaning they chew cud. The domestic sheep is thought to be descended from the wild mouflon of central and southwest Asia. Members of the genus are highly gregarious.
Female sheep are called ewes, males are called rams (sometimes also called bucks or tups) and young sheep are called lambs. The adjective applying to sheep is ovine and the collective term for sheep is flock or mob. The term herd is also occasionally used in this sense. See Glossary of sheep husbandry for other terms related to domestic sheep.
Sheep are usually stockier than other bovines and some have horns which are more divergent than those of goats. Sheep have scent glands on the face and hind feet. Communication through the scent glands is not well understood but is thought to be important for sexual signaling. Males can smell females which are fertile and ready to mate, and rams mark their territories by rubbing scent on to rocks. They have a four-chambered stomach which plays a vital role in digesting, regurgitating, and redigesting food. Domestic sheep are important for their wool, milk, and meat (which is called mutton or lamb).
Five species and numerous subspecies of sheep are currently recognized, although some subspecies have also been considered full species. The following are the main ones:
|120px||Ovis aries aries||Domestic sheep|
|120px||Ovis orientalis orientalis group||Mouflon|
|120px||Ovis orientalis vignei group||Urial|
|120px||Ovis canadensis||Bighorn sheep|
|120px||Ovis dalli||Dall Sheep|
|Ovis nivicola||Snow sheep|
Wild sheep are mostly found in hilly or mountainous habitats. They are fairly small compared to other ungulates; in most species adults weigh less than 100 kg (220 lb) (Nowak 1983). Their diet consists mainly of grasses, as well as other plants and lichens. Like other bovids their digestive system enables them to digest and live on low-quality, rough plant materials. Sheep conserve water well and can live in fairly dry environments. Their bodies are covered by a coat of thick hair to protect them from cold. The coat contains long, stiff hairs, called kemps, and a short woolly undercoat, called fleece, which grows in fall and is shed in spring.
Wild sheep are social animals and live in groups, called flocks. This helps them to avoid predators and also helps them stay warm in bad weather by huddling together. Flocks of sheep need to keep moving to find new grazing areas and more favorable climate as the seasons change. In each flock there is a sheep, usually a mature ram, which the others follow as a leader .
In wild sheep both rams and ewes have horns, with those of rams being much larger. The horns of a mature bighorn ram can weigh 14 kg (30 lb) – as much as the rest of its bones put together. Rams use their horns to fight with each other for dominance and for the right to mate with females. In most cases they do not injure each other because they hit each other head to head and their curved horns do not strike each other's bodies. They are also protected by having very thick skin and a double-layered skull.
Wild sheep have very keen senses of sight and hearing. When detecting predators wild sheep most often flee, usually uphill to higher ground. However they can also fight back. The Dall sheep has been known to butt wolves off the face of cliffs.
- Barbary Sheep (Ammotragus lervia), another type of goat antelope, not closely related to Ovis sheep.
- Blue sheep or bharal (Pseodois), two species of goat antelopes, not closely related to Ovis sheep.
- Domestic sheep
Because of their economic importance and ease of access most psychological orientated resarch on sheep has been conducted on the domestic sheep so the majority of references are in that article.
- Wilson & Reeder's Mammal species of the world 3rd edition online
- ICZN (International Commission on Zoological Nomenclature) opinion 2027
- Clutton-Brock, J. 1999. A Natural History of Domesticated Mammals. Cambridge, UK : Cambridge University Press ISBN 0521634954
- Voelker, W. 1986. The Natural History of Living Mammals. Medford, New Jersey: Plexus Publishing, Inc. ISBN 0937548081
- Bulanskey, S. 1992. The Covenant of the Wild. New York: William Morrow and Company, Inc. ISBN 0688096107
- Ciuti, S., Pipia, A., Ghiandai, F., Grignolio, S., & Apollonio, M. (2008). The key role of lamb presence in affecting flight response in Sardinian mouflon (Ovis orientalis musimon): Behavioural Processes Vol 77(3) Mar 2008, 408-412.
- Green, D. J. (2005). Review of Soay Sheep: Dynamics and Selection in an Island Population: Applied Animal Behaviour Science Vol 93(1-2) Sep 2005, 179-180.
- Mooring, M. S., Hart, B. L., Fitzpatrick, T. A., Reisig, D. D., Nishihira, T. T., Fraser, I. C., et al. (2006). Grooming in desert bighorn sheep (Ovis Canadensis Mexicana) and the ghost of parasites past: Behavioral Ecology Vol 17(3) May-Jun 2006, 364-371.
- Langbein, J., Streich, J., & Scheibe, K. M. (1998). Characteristic activity patterns of female mouflons (Ovis orientalis musimon) in the lambing period: Applied Animal Behaviour Science Vol 58(3-4) Jul 1998, 281-292.
- Loehr, J., Carey, J., Ylonen, H., & Suhonen, J. (2008). Coat darkness is associated with social dominance and mating behaviour in a mountain sheep hybrid lineage: Animal Behaviour Vol 76(5) Nov 2008, 1545-1553.
- Nowak, R. M. and J. L. Paradiso. 1983. Walker's Mammals of the World. Baltimore, Maryland: The Johns Hopkins University Press. ISBN 0801825253
- Parker, D. 2001. The Sheep Book. Athens, Ohio, USA : Ohio University Press ISBN 0804010323
- Perez-Barberia, F. J., Walker, D. M., & Marion, G. (2007). Maximizing intake under challenging foraging conditions at two spatial scales in Soay sheep: Animal Behaviour Vol 73(2) Feb 2007, 339-348.
- Toomer, E. E. (1997). The ethological characteristics and habitat of the desert bighorn sheep. Dissertation Abstracts International: Section B: The Sciences and Engineering.
- Miller, S. 1998. "Sheep and Goats". United States Department of Agriculture, Foreign Agricultural Service
- Oklahoma State University (OSU). 2003 Breeds of Livestock: Sheep Retrieved January 13, 2007
- Huffman, B. 2006. The Ultimate Ungulate Page Website Retrieved January 13, 2007
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