''Ovis'' is a genus of

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

s, part of the Caprinae

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

of the ruminant family Bovidae. Its seven highly sociable species are known as sheep or ovines. Domestic sheep are members of the genus, and are thought to be descended from the wild mouflon of

central Central is an adjective usually referring to being in the center of some place or (mathematical) object. Central may also refer to: Directions and generalised locations * Central Africa, a region in the centre of Africa continent, also known as ...

and southwest Asia.

Terminology

Female sheep are called ''ewes'', males are called ''rams'' or less frequently ''bucks'' or ''tups'', neutered males are called ''wethers'', 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 A herd is a social group of certain animals of the same species, either wild or domestic. The form of collective animal behavior associated with this is called ''herding''. These animals are known as gregarious animals. The term ''herd'' is ...

'' is also occasionally used in this sense, generally for large flocks. Many specialist terms relating to domestic sheep are used.

Characteristics

Sheep are fairly small compared to other ungulates; in most species, adults weigh less than .Nowak, R. M. and J. L. Paradiso. 1983. ''Walker's Mammals of the World''. Baltimore, Maryland: The Johns Hopkins University Press. Males are usually heavier than females by a significant amount. Wild sheep are mostly found in hilly or mountainous habitats. Their diets consist mainly of grasses, as well as other plants and

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.ruminants, they have four-chambered stomachs, which play a vital role in

digesting Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intest ...

food; they eructate, and rechew the

cud Cud is a portion of food that returns from a ruminant's stomach to the mouth to be chewed for the second time. More precisely, it is a bolus of semi-degraded food regurgitated from the reticulorumen of a ruminant. Cud is produced during the phy ...

to enable them to digest and live on low-quality, rough plant materials. Sheep conserve water well, and can live in fairly dry environments. The bodies of wild sheep (and some domestic breeds) are covered by a coat of thick

hair Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and f ...

to protect them from cold. This coat contains long, stiff hairs, called kemps, over a short, woolly undercoat, which grows in autumn and is shed in spring.Clutton-Brock, J. 1999. ''A Natural History of Domesticated Mammals''. Cambridge, UK : Cambridge University Press This woolly undercoat has been developed in many domestic sheep breeds into a fleece of long wool, with selection against kemp hairs in these breeds. The fleece covers the body (in a few breeds also the face and legs) and is used for

fibre Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...

. Domestic sheep are also reared for their milk and

meat Meat is animal flesh that is eaten as food. Humans have hunted, farmed, and scavenged animals for meat since prehistoric times. The establishment of settlements in the Neolithic Revolution allowed the domestication of animals such as chic ...

(which is called lamb or mutton depending on the age of the animal). In wild sheep, both rams and ewes have

horn Horn most often refers to: *Horn (acoustic), a conical or bell shaped aperture used to guide sound ** Horn (instrument), collective name for tube-shaped wind musical instruments *Horn (anatomy), a pointed, bony projection on the head of various ...

s, while in domestic sheep (depending upon

breed A breed is a specific group of domestic animals having homogeneous appearance (phenotype), homogeneous behavior, and/or other characteristics that distinguish it from other organisms of the same species. In literature, there exist several slig ...

) horns may be present in both rams and ewes, in rams only, or in neither. Rams' horns may be very large – those of a mature bighorn ram can weigh – as much as the bones of the rest of its body put together. Rams use their horns to fight with each other for dominance and 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 double-layered skulls.Voelker, W. 1986. ''The Natural History of Living Mammals''. Medford, New Jersey: Plexus Publishing, Inc. Wild sheep have very keen

senses A sense is a biological system used by an organism for sensation, the process of gathering information about the world through the detection of stimuli. (For example, in the human body, the brain which is part of the central nervous system rec ...

of sight and hearing. When detecting predators, wild sheep most often flee, usually to higher ground, but they can also fight back. The Dall sheep has been known to butt wolves off the face of cliffs. Sheep have scent glands on their faces and feet. Communication through the scent glands is not well understood, but is thought to be important for sexual signaling. Males can smell females that are in estrus, and rams mark their territories by rubbing scent on rocks.

Species

Seven species (and numerous subspecies) of sheep are currently recognized. The main recognized divisions are:

Behaviour

Sheep are social animals and live in groups, called flocks. This helps them to avoid predators and stay warm in cold weather by huddling together. Flocks of sheep need to keep moving to find new grazing areas and more favourable weather as the seasons change. In each flock, a sheep, usually a mature ram, is followed by the others. This "leader to follower" relationship can be both a positive and negative for flocks of ''Ovis aries''. Although there is safety in numbers, it has been reported that the following of one mature ram can bring flocks to slaughter in many situations where the mature ram misguides the flock.

Mating

Mating in sheep is characterized by males competing for females in estrus.

Social rank A social class is a grouping of people into a set of hierarchical social categories, the most common being the upper, middle and lower classes. Membership in a social class can for example be dependent on education, wealth, occupation, incom ...

in rams is established by male-male competition, known as the rut. Females select from dominant males based on sexually selected characteristics such as body size and horn size, as those traits are desirable in offspring. Females typically are separated from males outside the rut, but during the rut, females and males are found together. Females that are oestrous isolate themselves from other ewes, and may be less mobile. The rut is also linked with different ewe behaviour than during nonrutting periods. These changes are characterized by decreased feeding, increased time observing their surroundings, and increased behaviour changes. Ewes are also predicted to be slightly receptive to the displays of the rams.

References

*Bulanskey, S. 1992. ''The Covenant of the Wild''. New York: William Morrow and Company, Inc. *Parker, D. 2001. ''The Sheep Book''. Athens, Ohio, USA : Swallow Press / Ohio University Press

External links

Miller, S. 1998. "Sheep and Goats". United States Department of Agriculture, Foreign Agricultural Service
{{Authority control Sheep Mammal genera Taxa named by Carl Linnaeus