[2] It is much smaller than modern domesticated sheep but hardier, and is extraordinarily agile, tending to take refuge amongst the cliffs when frightened.

[3] In the early twentieth century, some Soay sheep were relocated to establish exotic flocks, such as the flock of "Park Soay" at Woburn Abbey, established by the Duke of Bedford in 1910, and selected for "primitive" characteristics.

The sheep exhibit a phenomenon known as overcompensatory density dependence, in which their population never reaches equilibrium.

[10] The age and sex structure of the population are important in determining when a crash happens; for instance, adult males enter winter in a poor condition after the autumn rut, whereas females have been grazing all summer and so enter winter in a good condition.

Survival rates of males (and lambs) are influenced by weather throughout winter (dependent on the strength of the North Atlantic Oscillation), whereas survival rates of females (and adolescents) are influenced most strongly by rainfall at the end of winter, when they will normally be heavily pregnant (the rain soaks the wool, increasing energy expenditure).

[9] Another factor in mortality rates is the loading of intestinal nematode parasites, particularly damaging in malnourished hosts.

[11] The sheep have short tails and naturally shed their wool, which can be hand plucked (called rooing) in the spring and early summer.

[12] The lambs are late maturing and produce smaller carcasses relative to commercial breeds.