WHO ARE THEY?

Sheep are quadrupedal, herbivorous, ruminant (foregut) mammals and are kept by humans as livestock. Like most ruminants, sheep are members of the order Artiodactyla, the even-toed ungulates, their relatives include alpacas, antelopes, camels, deer, giraffes, goats, hippopotamuses, llamas, peccaries, and pigs.

An adult female sheep is referred to as a ewe, an intact male as a ram or tup, a castrated male as a wether, and a young sheep as a lamb. Sheep have a pregnancy lasting about five months, and normal labour takes one to three hours.

Sheep have horizontal slit-shaped pupils, with excellent peripheral vision; with visual fields of about 270° to 320°, sheep can see behind themselves without turning their heads.

It has been reported that some sheep have apparently shown problem-solving abilities, it has also been shown they have good spatial understanding, can map out their surroundings mentally and may be able to plan ahead.

Sheep can recognise individual human and ovine faces, and remember them for years. In addition to long-term facial recognition of individuals, sheep can also differentiate emotional states through facial characteristics.

Sheep are highly social animals. If they become separated from their flock, their heart rates and levels of stress hormones increase. The flock means security and safety. Ewes nuzzle their lambs and mother and baby call to one another to reassure and to stop the youngster getting lost. If either become isolated, the vocal patterns change.

When stressed, sheep show signs of depression that we understand ourselves, such as hanging their heads.

The life expectancy of a domesticated sheep is 10-12 years, though some sheep may live as long as 20 years.

WHERE DID THEY COME FROM?

Artificially bred from the wild mouflon of Europe and Asia for an estimated 10,000 years, there are now hundreds of breeds, and they number a little over one billion.

Domestic sheep differ from their wild relatives and ancestors in several respects, having become neotenic (also called juvenilisation) as a result of selective breeding by humans.

HOW DO HUMANS USE THEM?

Sheep are raised for fleece, flesh, and milk. A sheep's wool is the most widely used animal fibre, and is usually harvested by shearing. Sheep are also occasionally raised as model organisms for science.

 The euphemisms for their flesh are 'lamb' when from young animals and 'mutton' when from older ones. 

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

In behavioural sciences, sheep have been used in isolated cases for the study of facial recognition, as their mental process of recognition is qualitatively similar to humans.

The video below gives an overview of how sheep are treated in Britain which likes to brag about "high welfare standards".