Sheep – Fluffy Ruminants And Other Sleep Clichés

Fall asleep learning about sheep, the wooly, sleepy icons of bedtime boredom. Learn about their grazing habits and social structure while not staying awake for any of it. Perfect for insomnia relief and sleepy trivia buffs.

Transcript

Welcome to the I Can Sleep Podcast,

Where I help you learn a little and sleep a lot.

I'm your host,

Benjamin Boster.

Tonight's episode is about sheep.

Sheep,

Or domestic sheep,

Are a domesticated,

Ruminant mammal,

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 sheep.

Like all ruminants,

Sheep are members of the order Arteodactyla,

The even-toed ungulates.

Numbering a little over one billion,

Domestic sheep are also the most numerous species of sheep.

A domestic sheep is an adult female is referred to as a ewe,

An intact male as a ram,

Occasionally a tup,

A castrated male as a weather,

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 purposes,

Sheep are raised for fleeces,

Meat,

And milk.

A sheep's wool is most widely used animal fiber,

And is usually harvested by shearing.

In Commonwealth countries,

Bovine meat is called lamb 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 animals,

Or as model organisms for science.

Sheep husbandry is practiced throughout the majority of the inhabited world,

And has been fundamental to many civilizations.

In the modern era,

Australia,

New Zealand,

The Southern and Central South American nations,

And the British Isles 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.

Use of the word sheep began in Middle English as a derivation of the Old English word sheep,

S-c-e-a-p.

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.

As a key animal in the history of farming,

Sheep have a deeply entrenched place in human culture,

And are represented in much modern language and symbolism.

As livestock,

Sheep are most often associated with pastoral,

Arcadian imagery.

Sheep figure in many mythologies,

Such as the Golden Fleece,

And major religions,

Especially the Abrahamic traditions.

In both ancient and modern religious ritual,

Sheep are used as sacrificial animals.

The exact line of descent from wild ancestors to domestic sheep is unclear.

The most common hypothesis states that Ovis ares is descended from the Asiatic species of Mufflin.

The European Mufflin 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,

000 to 20,

000 years earlier.

The domestication date is estimated to fall between 11,

000 and 9,

000 BC in Mesopotamia,

And possibly around 7,

000 BC in Mergar 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 suggests that selection for woolly sheep may have begun around 6,

000 BC,

And the earliest woven wool garments have been dated to 2,

000 to 3,

000 years later.

Sheep husbandry spread quickly in Europe.

Excavations show that in about 6,

000 BC,

During the Neolithic period of prehistory,

The Castelnovian people living around present-day Marseilles 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.

Ancient Romans kept sheep on a wide scale,

And were an important agent in the spread of sheep-raising.

Pliny the Elder in his Natural History,

Naturalis Historia,

Speaks at length about sheep and wool.

European colonists spread the practice of the New World from 1493 onwards.

Domestic sheep are relatively small ruminants,

Usually with a crimped hair called wool,

And often with horns forming a lateral spiral.

They differ from their wild relatives and ancestors in several respects,

Having become uniquely 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.

Pulled,

Or horns in both sexes,

Or in males only.

Most horned breeds have a single pair,

But a few breeds may have several.

Another trait unique to domestic sheep as compared to wild hovinds,

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.

Sheepkeepers also sometimes artificially paint smid marks onto their sheep in any pattern or color for identification.

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 trait in white flocks.

While white wool is desirable for large commercial markets,

There is a niche market for colored fleeces,

Mostly for hand spinning.

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 is a step in the commercial processing of the fiber.

Depending on breed,

Sheep show a range of heights and weights.

The rate of growth and mature weight is a heritable trait that is often selected for in breeding.

Ewes typically weigh between 45 and 100 kg,

And rams between 45 and 160 kg.

When all deciduous teeth have erupted,

The sheep have 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 upper jaw.

These are used to pick off vegetation,

Then the rear teeth grind it before it is swallowed.

There are 8 lower front teeth in ruminants,

But there is some disagreement as to whether these are 8 incisors,

Or 6 incisors and 2 incisor shaped canines.

This means that the dental formula for sheep is either 0.

0.

3.

34.

0.

3.

3,

Or 0.

0.

3.

33.

1.

3.

3.

There is a large diastema between the incisors and the molars.

In the first few years of life,

One can calculate the age of sheep from their front teeth,

As a pair of milk teeth is replaced by larger adult teeth each year.

The full set of 8 adult front teeth being complete at about 4 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 begin to slowly decline from 4 years on,

And the life expectancy of a sheep is 10-12 years,

Though some sheep may live as long as 20 years.

Sheep have good hearing,

And are sensitive to noise when being handled.

Sheep have horizontal,

Slid-shaped pupils,

With excellent peripheral vision,

With visual fields of about 270 degrees to 320 degrees.

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 pole 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.

Shadows and dips in the ground may cause sheep to balk.

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 glands 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.

Sheep and goats are closely related.

Both are in the subfamily Capernae.

However,

They are separate species,

So hybrids rarely occur.

And are always infertile.

A hybrid of a ewe and a bug,

A male goat,

Is called a sheep-goat hybrid,

Known as a jeep.

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.

The domestic sheep is a multi-purpose animal,

And the more than 200 breeds 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,

FAO,

With the estimated number varying somewhat from time to time,

E.

G.

863 breeds as of 1993,

1,

314 breeds as of 1995,

And 1,

229 breeds as of 2006.

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 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.

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 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.

Some major medium wool breeds,

Such as the Corydale,

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 cross-breeding to improve the attributes of other sheep types.

For example,

The American Columbia breed was developed by crossing Lincoln Rams,

A long-wool breed,

With fine-wooled,

Rambulate ewes.

Coarse or carpet 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 demands 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.

A minor class of sheep are the dairy 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.

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,

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.

Sheep are herbivorous.

Most breeds prefer to graze on grass and other short roughage,

Avoiding the taller,

Woody parts of plants that goats readily consume.

Both sheep and goats use their lips and tongues to select parts of the plant that are easier to digest or higher in nutrition.

Sheep,

However,

Graze well in monoculture pastures,

Where most goats fare poorly.

Like all ruminants,

Sheep have a complex digestive system composed of four chambers,

Allowing them to break down cellulose from stems,

Leaves,

And seed holes into simpler carbohydrates.

When sheep graze,

Vegetation is chewed into a mass called a bolus,

Which is then passed into the rumen via the reticulum.

The rumen is a 19-38 liter organ in which feed is fermented.

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.

After fermentation in the rumen,

Feed passes into the reticulum and the omasum.

Special feeds,

Such as grains,

May bypass the rumen altogether.

Food moves into the abomasum for final digestion before processing by the intestines.

The abomasum is the only one of the four chambers analogous to the human stomach,

And is sometimes called the true stomach.

Others 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 minerals,

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 that are lethal to sheep.

The same danger applies to mineral supplements,

Such as salt licks.

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 lawn-like grass,

But an array of grasses,

Legumes,

And forbs.

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,

Rhubarb,

Potato,

And rhododendron.

Sheep are largely grazing 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,

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,

Kudzu,

And spotted knapweed over native species such as sagebrush,

Making grazing sheep effective for conservation grazing.

Research conducted in Imperial County,

California,

Compared lamb grazing with herbicides for weed control in seedling alfalfa fields.

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

Entomologists also compared grazing lambs to insecticides for insect control in winter alfalfa.

In this trial,

Lambs provided insect control as effectively as insecticides.

Sheep grazing labor has also been used to a limited extent for controlling hazardous species such as giant hogweed.

Sheep are flock animals and strongly gregarious.

Much sheep behavior can be understood on the basis of these tendencies.

The dominance hierarchy 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.

Furthermore,

In contrast to the red deer and gazelle,

Two other ungulates of primary importance to meat production in prehistoric times,

Sheep do not defend territories,

Although they do form home ranges.

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 the leader may simply be the first individual to move.

Relationships and flocks tend to be closest among related sheep,

And 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 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 cold,

It must be retaught to the replacement animals.

Flock behavior 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 bud,

Or threatened 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.

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 dogs in this effort,

With a highly bred herding ability.

Sheep are food-oriented.

An association of humans with regular feeding often results in sheep soliciting people for food.

Those who are moving sheep may exploit this behavior by leading sheep with buckets of feed.

Sheep establish a dominance hierarchy through fighting,

Threats,

And competitiveness.

Dominant animals are inclined to be more aggressive with other sheep,

And usually feed first to troughs.

Primarily among rams,

Horn size is a factor in the flock hierarchy.

Rams with different sized horns may be less inclined to fight to establish the dominance order,

While rams with similarly sized horns are more so.

Marinos have an almost linear hierarchy,

Whereas there is a less rigid structure in border elastishers when a competitive feeding situation arises.

In sheep,

Position in a moving flock is highly correlated with social dominance,

But there is no definitive study to show consistent voluntary leadership by an individual sheep.

Sheep are frequently thought of as unintelligent animals.

Their flocking behavior and quickness to flee and panic can make sheep herding a difficult endeavor for the uninitiated.

Despite these perceptions,

A University of Illinois monograph on sheep reported their intelligence to be just below that of pigs,

And on par with that of cattle.

In a study published in Nature in 2001,

Kenneth M.

Kendrick and others reported,

Sheep recognize and are attracted to individual sheep and humans by their faces,

As they possess similar specialized neural systems in the temporal and frontal lobes.

Individual sheep can remember 50 other different sheep faces for over two years.

In addition to long-term facial recognition of individuals,

Sheep can also differentiate emotional states through facial characteristics.

If worked with patiently,

Sheep may learn their names,

And many sheep are trained to be led by halter for showing and other purposes.

Sheep have also responded well to clicker training.

Sheep have been used as pack animals.

Tibetan nomads distribute baggage equally throughout a flock as it is herded between living sites.

It has been reported that some sheep have apparently shown problem-solving abilities.

A flock in West Yorkshire,

England,

Allegedly found a way to get over cattle grids by rolling on their backs.

Although documentation of this has relied on anecdotal accounts.

Sounds made by domestic sheep include bleats,

Grunts,

Rumbles,

And snorts.

Bleating is used mostly for contact communication,

Especially between dam and lambs,

But also at times between other flock members.

The bleats of individual sheep are distinctive,

Enabling the ewe and her lambs to recognize each other's vocalizations.

Vocal communication between lambs and their dam declines to a very low level within several weeks after parturition.

A variety of bleats may be heard,

Depending on sheep age and circumstances.

Apart from contact communication,

Bleeding may signal distress,

Frustration,

Or impatience.

However,

Sheep are usually silent when in pain.

Isolation commonly prompts bleeding by sheep.

Pregnant ewes may grunt when in labor.

Rumbling sounds are made by the ram during courting.

Somewhat similar rumbling sounds may be made by the ewe,

Especially when with her neonate lambs.

A snort,

Explosive exhalation through the nostrils,

May signal aggression or a warning,

And is often elicited from startled sheep.

Reviews

Gives a new meaning to counting sheep! Eeerrrrr….wool? Thanks Benjamin!! Super boring…..😂

I counted one sheep before I was out like a light.

I lost count of the 🐏🐑🐏🐑
I just have to listen again. 🥱😴