Sheep or domestic sheep (''Ovis aries'') are domesticated,

ruminant Ruminants ( suborder Ruminantia) are hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. Th ...

mammals typically kept as

livestock Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to anima ...

. Although the term ''sheep'' can apply to other species in the genus '' Ovis'', in everyday usage it almost always refers to domesticated sheep. Like all ruminants, sheep are members of the

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

Artiodactyla The even-toed ungulates (Artiodactyla , ) are ungulates—hoofed animals—which bear weight equally on two (an even number) of their five toes: the third and fourth. The other three toes are either present, absent, vestigial, or pointing poste ...

, the

even-toed ungulate The even-toed ungulates (Artiodactyla , ) are ungulates—hoofed animals—which bear weight equally on two (an even number) of their five toes: the third and fourth. The other three toes are either present, absent, vestigial, or pointing post ...

s. Numbering a little over one billion, domestic sheep are also the most numerous species of sheep. An adult female is referred to as a ''ewe'' (), an intact male as a ''ram'', occasionally a ''tup'', a

castrated Castration is any action, surgical, chemical, or otherwise, by which an individual loses use of the testicles: the male gonad. Surgical castration is bilateral orchiectomy (excision of both testicles), while chemical castration uses phar ...

male as a ''wether'', and a young sheep as a ''lamb''. Sheep are most likely descended from the wild mouflon of Europe and Asia, with Iran being a geographic envelope of the domestication center. One of the earliest animals to be domesticated for

agricultural Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled peopl ...

purposes, sheep are raised for fleeces, meat (lamb, hogget or mutton) and

milk Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digest solid food. Immune factors and immune-modulati ...

. A sheep's

wool Wool is the textile fibre obtained from sheep and other mammals, especially goats, rabbits, and camelids. The term may also refer to inorganic materials, such as mineral wool and glass wool, that have properties similar to animal wool. ...

is the most widely used animal fiber, and is usually harvested by shearing. In Commonwealth countries,

ovine Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus '' Ovis'', in everyday usage it almost always refers to domesticated ...

meat is called

lamb Lamb or The Lamb may refer to: * A young sheep * Lamb and mutton, the meat of sheep Arts and media Film, television, and theatre * ''The Lamb'' (1915 film), a silent film starring Douglas Fairbanks Sr. in his screen debut * ''The Lamb'' (1918 ...

when from younger animals and mutton when from older ones; in the United States, meat from both older and younger animals is usually called lamb. Sheep continue to be important for wool and meat today, and are also occasionally raised for pelts, as

dairy A dairy is a business enterprise established for the harvesting or processing (or both) of animal milk – mostly from cows or buffaloes, but also from goats, sheep, horses, or camels – for human consumption. A dairy is typically located on ...

animals, or as model organisms for science. Sheep husbandry is practised throughout the majority of the inhabited world, and has been fundamental to many civilizations. In the modern era, Australia,

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 List of islands of New Zealand, smaller islands. It is the ...

, the southern and central

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

n nations, and the

British Isles The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles (O ...

are most closely associated with sheep production. There is a large lexicon of unique terms for sheep husbandry which vary considerably by region and

dialect The term dialect (from Latin , , from the Ancient Greek word , 'discourse', from , 'through' and , 'I speak') can refer to either of two distinctly different types of linguistic phenomena: One usage refers to a variety of a language that ...

. Use of the word ''sheep'' began in

Middle English Middle English (abbreviated to ME) is a form of the English language that was spoken after the Norman conquest of 1066, until the late 15th century. The English language underwent distinct variations and developments following the Old English ...

as a derivation of the Old English word '; it is both the singular and plural name for the animal. A group of sheep is called a flock. Many other specific terms for the various life stages of sheep exist, generally related to lambing, shearing, and age. Being a key animal in the history of farming, sheep have a deeply entrenched place in human culture, and find representation in much modern language and

symbology A symbol is a mark, sign, or word that indicates, signifies, or is understood as representing an idea, object, or relationship. Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very different conc ...

. As livestock, sheep are most often associated with

pastoral A pastoral lifestyle is that of shepherds herding livestock around open areas of land according to seasons and the changing availability of water and pasture. It lends its name to a genre of literature, art, and music ( pastorale) that de ...

Arcadian Arcadian may refer to: * Arcadian, someone or something from, or related to: ** Arcadia (region), the ancient Greek region ** Arcadia (regional unit), the region in modern Greece ** Accademia degli Arcadi, the Italian literary academy founded in ...

imagery. Sheep figure in many

mythologies Myth is a folklore genre consisting of Narrative, narratives that play a fundamental role in a society, such as foundational tales or Origin myth, origin myths. Since "myth" is widely used to imply that a story is not Objectivity (philosophy), ...

—such as the

Golden Fleece In Greek mythology, the Golden Fleece ( el, Χρυσόμαλλον δέρας, ''Chrysómallon déras'') is the fleece of the golden-woolled,, ''Khrusómallos''. winged ram, Chrysomallos, that rescued Phrixus and brought him to Colchis, wh ...

—and major religions, especially the

Abrahamic The Abrahamic religions are a group of religions centered around worship of the God of Abraham. Abraham, a Hebrew patriarch, is extensively mentioned throughout Abrahamic religious scriptures such as the Bible and the Quran. Jewish tradition ...

traditions. In both ancient and modern religious ritual, sheep are used as sacrificial animals.

History

The exact line of descent from wild ancestors to domestic sheep is unclear. The most common hypothesis states that ''Ovis aries'' is descended from the Asiatic (''O. gmelini'') species of mouflon; the European mouflon (''Ovis aries musimon'') is a direct descendant of this population. Sheep were among the first animals to be domesticated by humankind (although the domestication of dogs probably took place 10 to 20 thousand years earlier); the domestication date is estimated to fall between 11,000 and 9,000 B.C in

Mesopotamia Mesopotamia ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن or ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the northern part of the F ...

Ensminger, p. 4Weaver, pp. 11–14Simmons & Ekarius, p. 2 and possibly around 7,000 B.C. in

Mehrgarh Mehrgarh (; ur, ) is a Neolithic archaeological site (dated ) situated on the Kacchi Plain of Balochistan in Pakistan. It is located near the Bolan Pass, to the west of the Indus River and between the modern-day Pakistani cities of Quetta ...

in the Indus Valley. The rearing of sheep for secondary products, and the resulting breed development, began in either southwest Asia or western Europe. Initially, sheep were kept solely for meat, milk and skins. Archaeological evidence from statuary found at sites in

Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkm ...

suggests that selection for woolly sheep may have begun around 6000 BC,Ensminger, p. 5Weaver, p. 11 and the earliest woven wool garments have been dated to two to three thousand years later.Smith et al., p. 8 Sheep husbandry spread quickly in Europe. Excavations show that in about 6000 BC, during the

Neolithic The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several part ...

period of prehistory, the Castelnovien people, living around Châteauneuf-les-Martigues near present-day

Marseille Marseille ( , , ; also spelled in English as Marseilles; oc, Marselha ) is the prefecture of the French department of Bouches-du-Rhône and capital of the Provence-Alpes-Côte d'Azur region. Situated in the camargue region of southern Fran ...

in the south of France, were among the first in Europe to keep domestic sheep. Practically from its inception, ancient Greek civilization relied on sheep as primary livestock, and were even said to name individual animals.Weaver, p. 13

Ancient Romans In modern historiography, ancient Rome refers to Roman civilisation from the founding of the city of Rome in the 8th century BC to the collapse of the Western Roman Empire in the 5th century AD. It encompasses the Roman Kingdom (753–509 B ...

kept sheep on a wide scale, and were an important agent in the spread of sheep raising.

Pliny the Elder Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman author, naturalist and natural philosopher, and naval and army commander of the early Roman Empire, and a friend of the emperor Vespasian. He wrote the encyclopedic ...

, in his Natural History (''Naturalis Historia''), speaks at length about sheep and wool. European colonists spread the practice to the

New World The term ''New World'' is often used to mean the majority of Earth's Western Hemisphere, specifically the Americas."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: Oxford University Press, p. ...

from 1493 onwards.EnsmingerWeaver, p. 12

Characteristics

Domestic sheep are relatively small ruminants, usually with a crimped hair called wool and often with horns forming a

lateral Lateral is a geometric term of location which may refer to: Healthcare *Lateral (anatomy), an anatomical direction * Lateral cricoarytenoid muscle * Lateral release (surgery), a surgical procedure on the side of a kneecap Phonetics *Lateral co ...

spiral In mathematics, a spiral is a curve which emanates from a point, moving farther away as it revolves around the point. Helices Two major definitions of "spiral" in the American Heritage Dictionary are:neotenic as a result of selective breeding by humans. A few primitive breeds of sheep retain some of the characteristics of their wild cousins, such as short tails. Depending on breed, domestic sheep may have no horns at all (i.e. polled), or horns in both sexes, or in males only. Most horned breeds have a single pair, but a few breeds may have several. Turkmen sheep

Another trait unique to domestic sheep as compared to wild ovines is their wide variation in color. Wild sheep are largely variations of brown hues, and variation within species is extremely limited. Colors of domestic sheep range from pure white to dark chocolate brown, and even spotted or

piebald A piebald or pied animal is one that has a pattern of unpigmented spots (white) on a pigmented background of hair, feathers or scales. Thus a piebald black and white dog is a black dog with white spots. The animal's skin under the white backgro ...

. Selection for easily dyeable white fleeces began early in sheep domestication, and as white wool is a dominant trait it spread quickly. However, colored sheep do appear in many modern breeds, and may even appear as a

recessive In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and ...

trait in white flocks. While white wool is desirable for large commercial markets, there is a niche market for colored fleeces, mostly for handspinning.Weaver The nature of the fleece varies widely among the breeds, from dense and highly crimped, to long and hairlike. There is variation of wool type and quality even among members of the same flock, so

wool classing Wool classing is the production of uniform, predictable, low-risk lines of wool, carried out by examining the characteristics of the wool in its raw state and classing (grading) it accordingly. Wool classing is done by a wool classer. Basis for ...

is a step in the commercial processing of the fibre. Take ours!

Depending on breed, sheep show a range of heights and weights. Their rate of growth and mature weight is a

heritable Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic inf ...

trait that is often selected for in breeding. Ewes typically weigh between , and rams between . When all deciduous teeth have erupted, the sheep has 20 teeth. Mature sheep have 32 teeth. As with other ruminants, the front teeth in the lower jaw bite against a hard, toothless pad in the upper jaw. These are used to pick off vegetation, then the rear teeth grind it before it is swallowed. There are eight lower front teeth in ruminants, but there is some disagreement as to whether these are eight

incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, w ...

s, or six incisors and two incisor-shaped canines. This means that the

dental formula Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiolog ...

for sheep is either or There is a large diastema between the

s and the

molars The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...

. In the first few years of life one can calculate the age of sheep from their front teeth, as a pair of

milk teeth Deciduous teeth or primary teeth, also informally known as baby teeth, milk teeth, or temporary teeth,Illustrated Dental Embryology, Histology, and Anatomy, Bath-Balogh and Fehrenbach, Elsevier, 2011, page 255 are the first set of teeth in th ...

is replaced by larger adult teeth each year, the full set of eight adult front teeth being complete at about four years of age. The front teeth are then gradually lost as sheep age, making it harder for them to feed and hindering the health and productivity of the animal. For this reason, domestic sheep on normal

pasture Pasture (from the Latin ''pastus'', past participle of ''pascere'', "to feed") is land used for grazing. Pasture lands in the narrow sense are enclosed tracts of farmland, grazed by domesticated livestock, such as horses, cattle, sheep, or s ...

begin to slowly decline from four years on, and the life expectancy of a sheep is 10 to 12 years, though some sheep may live as long as 20 years.Smith et al. Crâne mouton

Sheep have good hearing, and are sensitive to noise when being handled.Smith et al., p. 5. Sheep have horizontal slit-shaped pupils, with excellent

peripheral vision Peripheral vision, or ''indirect vision'', is vision as it occurs outside the point of fixation, i.e. away from the center of gaze or, when viewed at large angles, in (or out of) the "corner of one's eye". The vast majority of the area in the ...

; with visual fields of about 270° to 320°, sheep can see behind themselves without turning their heads. Many breeds have only short hair on the face, and some have facial wool (if any) confined to the poll and or the area of the mandibular angle; the wide angles of peripheral vision apply to these breeds. A few breeds tend to have considerable wool on the face; for some individuals of these breeds, peripheral vision may be greatly reduced by "wool blindness", unless recently shorn about the face. Sheep have poor

depth perception Depth perception is the ability to perceive distance to objects in the world using the visual system and visual perception. It is a major factor in perceiving the world in three dimensions. Depth perception happens primarily due to stereopsi ...

; shadows and dips in the ground may cause sheep to baulk. In general, sheep have a tendency to move out of the dark and into well-lit areas, and prefer to move uphill when disturbed. Sheep also have an excellent sense of smell, and, like all species of their genus, have

scent gland Scent gland are exocrine glands found in most mammals. They produce semi-viscous secretions which contain pheromones and other semiochemical compounds. These odor-messengers indicate information such as status, territorial marking, mood, and s ...

s just in front of the eyes, and interdigitally on the feet. The purpose of these glands is uncertain, but those on the face may be used in breeding behaviors. The foot glands might also be related to reproduction, but alternative functions, such as secretion of a waste product or a scent marker to help lost sheep find their flock, have also been proposed.Smith et al., p. 4.

Comparison with goats

Sheep and

goat The goat or domestic goat (''Capra hircus'') is a domesticated species of goat-antelope typically kept as livestock. It was domesticated from the wild goat (''C. aegagrus'') of Southwest Asia and Eastern Europe. The goat is a member of ...

s are closely related: both are in the subfamily

Caprinae The subfamily Caprinae, also sometimes referred to as the tribe Caprini, is part of the ruminant family Bovidae, and consists of mostly medium-sized bovids. A member of this subfamily is called a caprine, or, more informally, a goat-antelope ( ...

. However, they are separate species, so hybrids rarely occur and are always infertile. A hybrid of a ewe and a buck (a male goat) is called a sheep-goat hybrid, known as ''geep''. Visual differences between sheep and goats include the beard of goats and divided upper lip of sheep. Sheep tails also hang down, even when short or docked, while the short tails of goats are held upwards. Also, sheep breeds are often naturally polled (either in both sexes or just in the female), while naturally polled goats are rare (though many are polled artificially). Males of the two species differ in that buck goats acquire a unique and strong odor during the rut, whereas rams do not.

Breeds

The domestic sheep is a multi-purpose animal, and the more than 200

breeds 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 ...

now in existence were created to serve these diverse purposes. Some sources give a count of a thousand or more breeds, but these numbers cannot be verified, according to some sources. However, several hundred breeds of sheep have been identified by the

Food and Agriculture Organization of the UN The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...

(FAO), with the estimated number varying somewhat from time to time: e.g. 863 breeds as of 1993, 1314 breeds as of 1995 and 1229 breeds as of 2006.FAO. 2007. State of the world's animal genetic resources for food and agriculture (These numbers exclude extinct breeds, which are also tallied by the FAO.) For the purpose of such tallies, the FAO definition of a breed is "either a subspecific group of domestic livestock with definable and identifiable external characteristics that enable it to be separated by visual appraisal from other similarly defined groups within the same species or a group for which geographical and/or cultural separation from phenotypically similar groups has led to acceptance of its separate identity." Almost all sheep are classified as being best suited to furnishing a certain product: wool, meat, milk, hides, or a combination in a dual-purpose breed. Other features used when classifying sheep include face color (generally white or black), tail length, presence or lack of horns, and the

topography Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary s ...

for which the breed has been developed. This last point is especially stressed in the UK, where breeds are described as either upland (hill or mountain) or lowland breeds. A sheep may also be of a fat-tailed type, which is a dual-purpose sheep common in Africa and Asia with larger deposits of fat within and around its tail. Barbados Blackbelly

Breeds are often categorized by the type of their wool. Fine wool breeds are those that have wool of great crimp and density, which are preferred for textiles. Most of these were derived from

Merino The Merino is a breed or group of breeds of domestic sheep, characterised by very fine soft wool. It was established in Spain near the end of the Middle Ages, and was for several centuries kept as a strict Spanish monopoly; exports of the bree ...

sheep, and the breed continues to dominate the world sheep industry. Downs breeds have wool between the extremes, and are typically fast-growing meat and ram breeds with dark faces.D’Arcy, J.B., Sheep Management & Wool Technology, NSW University Press, 1986, Some major medium wool breeds, such as the

Corriedale The Corriedale is a New Zealand breed of sheep. It was bred from about 1882 in the South Island by James Little, who cross-bred Merino and Lincoln Longwool sheep. The breed was officially recognised in 1911. It has been exported to Australia a ...

, are dual-purpose crosses of long and fine-wooled breeds and were created for high-production commercial flocks. Long wool breeds are the largest of sheep, with long wool and a slow rate of growth. Long wool sheep are most valued for crossbreeding to improve the attributes of other sheep types. For example: the American

Columbia Columbia may refer to: * Columbia (personification), the historical female national personification of the United States, and a poetic name for America Places North America Natural features * Columbia Plateau, a geologic and geographic region in ...

breed was developed by crossing Lincoln rams (a long wool breed) with fine-wooled

Rambouillet Rambouillet (, , ) is a subprefecture of the Yvelines department in the Île-de-France region of France. It is located beyond the outskirts of Paris, southwest of its centre. In 2018, the commune had a population of 26,933. Rambouillet l ...

ewes. Coarse or

carpet A carpet is a textile floor covering typically consisting of an upper layer of pile attached to a backing. The pile was traditionally made from wool, but since the 20th century synthetic fibers such as polypropylene, nylon, or polyester hav ...

wool sheep are those with a medium to long length wool of characteristic coarseness. Breeds traditionally used for carpet wool show great variability, but the chief requirement is a wool that will not break down under heavy use (as would that of the finer breeds). As the demand for carpet-quality wool declines, some breeders of this type of sheep are attempting to use a few of these traditional breeds for alternative purposes. Others have always been primarily meat-class sheep.Wooster A minor class of sheep are the

breeds. Dual-purpose breeds that may primarily be meat or wool sheep are often used secondarily as milking animals, but there are a few breeds that are predominantly used for milking. These sheep produce a higher quantity of milk and have slightly longer lactation curves. In the quality of their milk, the fat and protein content percentages of dairy sheep vary from non-dairy breeds, but lactose content does not.Pulina et al. p. 2. A last group of sheep breeds is that of fur or hair sheep, which do not grow wool at all. Hair sheep are similar to the early domesticated sheep kept before woolly breeds were developed, and are raised for meat and pelts. Some modern breeds of hair sheep, such as the

Dorper The Dorper is a South African breed of domestic sheep developed by crossing Dorset Horn and the Blackhead Persian sheep. The breed was created through the efforts of the South African Department of Agriculture to breed a meat Meat is ...

, result from crosses between wool and hair breeds. For meat and hide producers, hair sheep are cheaper to keep, as they do not need shearing. Hair sheep are also more resistant to parasites and hot weather. With the modern rise of corporate

agribusiness Agribusiness is the industry, enterprises, and the field of study of value chains in agriculture and in the bio-economy, in which case it is also called bio-business or bio-enterprise. The primary goal of agribusiness is to maximize profit w ...

and the decline of localized

family farm A family farm is generally understood to be a farm owned and/or operated by a family; it is sometimes considered to be an Estate (land), estate passed down by inheritance. Although a recurring conceptual model, conceptual and archetype, archet ...

s, many breeds of sheep are in danger of extinction. The

Rare Breeds Survival Trust The Rare Breeds Survival Trust is a conservation charity whose purpose is to secure the continued existence and viability of the native farm animal genetic resources (FAnGR) of the United Kingdom. It was founded in 1973 by Joe Henson to pres ...

of the UK lists 22 native breeds as having only 3,000 registered animals (each), and The Livestock Conservancy lists 14 as either "critical" or "threatened". Preferences for breeds with uniform characteristics and fast growth have pushed heritage (or heirloom) breeds to the margins of the sheep industry. Those that remain are maintained through the efforts of conservation organizations, breed registries, and individual farmers dedicated to their preservation.

Diet

Sheep are

herbivorous A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

mammals. Most breeds prefer to graze on

grass Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in law ...

and other short

roughage Dietary fiber (in British English fibre) or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Dietary fibers are diverse in chemical composition, and can be grouped generally by the ...

, avoiding the taller woody parts of plants that goats readily consume.Pugh, pp. 19. Both sheep and goats use their lips and

tongue The tongue is a muscular organ in the mouth of a typical tetrapod. It manipulates food for mastication and swallowing as part of the digestive process, and is the primary organ of taste. The tongue's upper surface (dorsum) is covered by taste bu ...

s to select parts of the plant that are easier to digest or higher in nutrition. Sheep, however, graze well in

monoculture In agriculture, monoculture is the practice of growing one crop species in a field at a time. Monoculture is widely used in intensive farming and in organic farming: both a 1,000-hectare/acre cornfield and a 10-ha/acre field of organic kale a ...

pastures where most goats fare poorly. Rumen-sheep2

Like all ruminants, sheep have a complex digestive system composed of four chambers, allowing them to break down

cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall ...

from stems, leaves, and seed hulls into simpler

carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or ...

s. When sheep graze, vegetation is chewed into a mass called a

bolus Bolus may refer to: Geography * Bolus, Iran, a village in Ardabil Province, Iran * Bolus, or Baulus, an Anatolian village on the site of ancient Berissa Medicine * Bolus (digestion), a ball-shaped mass moving through the digestive tract * Bolus ...

, which is then passed into the

rumen The rumen, also known as a paunch, is the largest stomach compartment in ruminants and the larger part of the reticulorumen, which is the first chamber in the alimentary canal of ruminant animals. The rumen's microbial favoring environment allow ...

, via the reticulum. The rumen is a 19- to 38-liter (5 to 10 gallon) organ in which feed is

fermented Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food p ...

.Simmons & Ekarius, p. 146. The fermenting organisms include bacteria, fungi, and protozoa. (Other important rumen organisms include some archaea, which produce methane from carbon dioxide.) The bolus is periodically regurgitated back to the mouth as cud for additional chewing and

salivation Saliva (commonly referred to as spit) is an extracellular fluid produced and secreted by salivary glands in the mouth. In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which DNA can b ...

. After fermentation in the rumen, feed passes into the reticulum and the omasum; special feeds such as grains may bypass the rumen altogether. After the first three chambers, food moves into the

abomasum The abomasum, also known as the maw,The Cham ...

for final digestion before processing by the

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans a ...

s. The abomasum is the only one of the four chambers analogous to the human stomach, and is sometimes called the "true stomach". Other than forage, the other staple feed for sheep is hay, often during the winter months. The ability to thrive solely on pasture (even without hay) varies with breed, but all sheep can survive on this diet. Also included in some sheep's diets are

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ...

s, either in a trace mix or in licks. Feed provided to sheep must be specially formulated, as most cattle, poultry, pig, and even some goat feeds contain levels of

copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish ...

that are lethal to sheep. The same danger applies to mineral supplements such as

salt lick A mineral lick (also known as a salt lick) is a place where animals can go to lick essential mineral nutrients from a deposit of salts and other minerals. Mineral licks can be naturally occurring or artificial (such as blocks of salt that farm ...

Grazing behavior

Sheep follow a diurnal pattern of activity, feeding from dawn to dusk, stopping sporadically to rest and chew their cud. Ideal pasture for sheep is not lawnlike grass, but an array of

es,

legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock fo ...

s and

forb A forb or phorb is an herbaceous flowering plant that is not a graminoid (grass, sedge, or rush). The term is used in biology and in vegetation ecology, especially in relation to grasslands and understory. Typically these are dicots without woo ...

s. Types of land where sheep are raised vary widely, from pastures that are seeded and improved intentionally to rough, native lands. Common plants toxic to sheep are present in most of the world, and include (but are not limited to) cherry, some oaks and acorns, tomato,

yew Yew is a common name given to various species of trees. It is most prominently given to any of various coniferous trees and shrubs in the genus ''Taxus'': * European yew or common yew (''Taxus baccata'') * Pacific yew or western yew (''Taxus br ...

, rhubarb, potato, and

rhododendron ''Rhododendron'' (; from Ancient Greek ''rhódon'' "rose" and ''déndron'' "tree") is a very large genus of about 1,024 species of woody plants in the heath family (Ericaceae). They can be either evergreen or deciduous. Most species are nativ ...

Effects on pasture

Sheep are largely

grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and other ...

herbivores, unlike browsing animals such as goats and deer that prefer taller foliage. With a much narrower face, sheep crop plants very close to the ground and can overgraze a pasture much faster than cattle. For this reason, many shepherds use

managed intensive rotational grazing In agriculture, rotational grazing, as opposed to continuous grazing, describes many systems of pasturing, whereby livestock are moved to portions of the pasture, called paddocks, while the other portions rest. Each paddock must provide all the n ...

, where a flock is rotated through multiple pastures, giving plants time to recover. Paradoxically, sheep can both cause and solve the spread of invasive plant species. By disturbing the natural state of pasture, sheep and other livestock can pave the way for invasive plants. However, sheep also prefer to eat invasives such as cheatgrass,

leafy spurge Leafy spurge may refer to several species of plant in the genus ''Euphorbia'', including: * '' Euphorbia esula'', native to central and southern Europe * ''Euphorbia virgata ''Euphorbia virgata'', commonly known as leafy spurge, wolf's milk leaf ...

kudzu Kudzu (; also called Japanese arrowroot or Chinese arrowroot) is a group of climbing, coiling, and trailing deciduous perennial vines native to much of East Asia, Southeast Asia, and some Pacific islands, but invasive in many parts of the wor ...

and spotted knapweed over native species such as

sagebrush Sagebrush is the common name of several woody and herbaceous species of plants in the genus '' Artemisia''. The best known sagebrush is the shrub '' Artemisia tridentata''. Sagebrushes are native to the North American west. Following is an al ...

, making grazing sheep effective for

conservation grazing Conservation grazing or targeted grazing is the use of semi- feral or domesticated grazing livestock to maintain and increase the biodiversity of natural or semi-natural grasslands, heathlands, wood pasture, wetlands and many other habitats.

. Research conducted in

Imperial County, California Imperial County is a county on the southeast border of the U.S. state of California. As of the 2020 census, the population was 179,702, making it the least populous county in Southern California. The county seat is El Centro. Imperial is the ...

compared lamb grazing with

herbicides Herbicides (, ), also commonly known as weedkillers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page fo ...

for

weed A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place", or a plant growing where it is not wanted.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. ...

control in seedling alfalfa fields. Three trials demonstrated that grazing lambs were just as effective as herbicides in controlling winter weeds.

Entomologist Entomology () is the scientific study of insects, a branch of zoology. In the past the term "insect" was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such as arach ...

s also compared grazing lambs to

insecticides Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed t ...

for insect control in winter alfalfa. In this trial, lambs provided insect control as effectively as insecticides.

Behavior

Flock behavior

Sheep are flock animals and strongly gregarious; much sheep behavior can be understood on the basis of these tendencies. The

dominance hierarchy In biology, a dominance hierarchy (formerly and colloquially called a pecking order) is a type of social hierarchy that arises when members of animal social groups interact, creating a ranking system. A dominant higher-ranking individual is so ...

of sheep and their natural inclination to follow a leader to new pastures were the pivotal factors in sheep being one of the first domesticated livestock species.Budiansky Furthermore, in contrast to the

red deer The red deer (''Cervus elaphus'') is one of the largest deer species. A male red deer is called a stag or hart, and a female is called a hind. The red deer inhabits most of Europe, the Caucasus Mountains region, Anatolia, Iran, and parts of wes ...

and

gazelle A gazelle is one of many antelope species in the genus ''Gazella'' . This article also deals with the seven species included in two further genera, ''Eudorcas'' and '' Nanger'', which were formerly considered subgenera of ''Gazella''. A third ...

(two other ungulates of primary importance to meat production in prehistoric times), sheep do not defend territories although they do form

home ranges A home range is the area in which an animal lives and moves on a periodic basis. It is related to the concept of an animal's territory which is the area that is actively defended. The concept of a home range was introduced by W. H. Burt in 1943. He ...

.Clutton-Brock, J., (1987). A Natural History of Domesticated Mammals. Cambridge University Press, Cambridge pp.55 All sheep have a tendency to congregate close to other members of a flock, although this behavior varies with breed, and sheep can become stressed when separated from their flock members. During flocking, sheep have a strong tendency to follow, and a leader may simply be the first individual to move. Relationships in flocks tend to be closest among related sheep: in mixed-breed flocks, subgroups of the same breed tend to form, and a ewe and her direct descendants often move as a unit within large flocks. Sheep can become

hefted The raising of domestic sheep has occurred in nearly every inhabited part of the globe, and the variations in cultures and languages which have kept sheep has produced a vast lexicon of unique terminology used to describe sheep husbandry. Terms ...

to one particular local pasture (heft) so they do not roam freely in unfenced landscapes. Lambs learn the heft from ewes and if whole flocks are culled it must be retaught to the replacement animals. Flock behaviour in sheep is generally only exhibited in groups of four or more sheep; fewer sheep may not react as expected when alone or with few other sheep. Being a prey species, the primary defense mechanism of sheep is to flee from danger when their flight zone is entered. Cornered sheep may charge and butt, or threaten by hoof stamping and adopting an aggressive posture. This is particularly true for ewes with newborn lambs. In regions where sheep have no natural predators, none of the native breeds of sheep exhibit a strong flocking behavior.

Herding

Farmers exploit flocking behavior to keep sheep together on unfenced pastures such as hill farming, and to move them more easily. For this purpose shepherds may use

herding dog A he