Colour and Coat Pattern in Soay sheep
Dark Phase, Light Phase, a Definition
Soay sheep on St. Kilda and also those on the mainland, have a wide variety of fleece colours which cause much confusion when putting a name to a colour type. Island Survivors was the first book to give descriptions of the various colours and it is the resource most subsequent literature refers to. Our comments here are based on those descriptions and our own personal observations of sheep on St. Kilda.
Dark and light phase Soay with a variety of shades resting mid-day on Ruaival
There are two basic colours of Soay; dark phase and light phase and two basic coat patterns within each of these colours, "mouflon or wild” and "self". Most of the sheep on St. Kilda are dark and about one third are light. However, this proportion seems to be changing over time. The majority of both dark and light animals have a "mouflon" pattern of markings named such because of its similarity to wild mouflon sheep, a probable ancestor. It is also referred to as "wild" because of the light belly which is found in wild sheep. Soay are the only domestic sheep to retain this primitive trait. This contrasting pale colour is also shown on the face where the area surrounding the eyes, the corner of the mouth and throat are some shade of white. The belly and rump areas and the inside of the legs often match this light marking. A very small portion are referred to "self colour " these animals have no contrasting pale fleece.
Dark and light phase sheep facing each other
Dark Phase mouflon/wild coat pattern
Most dark phase sheep have the "mouflon" or "wild" pattern but these marks vary a great deal with individual animals. Some have a distinct demarcation line between a very dark brown main fleece of the body and the very light markings of the face, legs and rump, but this is not always the case, with some the "wild "markings are almost obscured . Some dark phase sheep also have a much lighter brown coat ( these animals very likely have one light phase parent) .
Distinctly marked dark mouflon/wild Soay ram, Hirta
Two dark phase mouflon/wild Soay rams, Hirta
A variety of shades of dark phase rams Hirta
Dark phase self coat pattern
The sheep with this fleece type are described as "self black" and/or "self dark or self dark brown" They have no contrasting markings on their faces, body or belly. All such sheep are born as uniformly black or dark chocolate brown lambs and either remain dark or become much paler- "light phase in fact." (Jewell 1974)
Dark phase self ewe, Hirta
Light phase mouflon/wild coat pattern
The sheep with this colouration are a much lighter version of dark phase. The main body colour is a light fawn brown color with the same lighter markings around the eyes, mouth, throat, belly, rump and inside the legs as dark phase animals The fawn body colour varies with individuals with some almost a biscuit colour to others which are a much darker tan. These variations have caused many different names to be used for the base colour of light phase animals. They are frequently also called "Blond" or "Tan".
Light phase mouflon/wild Soay ram, Hirta
Very light light phase mouflon/wild ewes, Hirta
Light phase mouflon/wild pattern, dark phase lamb next to its mother (center), Hirta
Light phase self coat pattern
The lambs that will mature to be this colouration are usually born with a uniform dark russet chocolate colour. As they grow, their fleeces becomes lighter but the face and legs usually stay darker than the rest of the body. The contrasting eye, mouth, throat, belly and rump markings are absent.
Light phase self ewe, Hirta
Non typical colourations
The majority of the sheep on St. Kilda have the fleece colouration's described above, but there are a very few that are different. These animals stand out and are easy to distinguish. In some cases the differences are small but very occasionally a real oddity occurs, primarily white in an unusual area of the fleece. White on the poll of the head is the most common, however, white on the face which can cover the whole head and half white legs are seen. The extreme example is the piebald with large white patches on the back and flank. While very rare, they do occur.
Light phase mouflon/wild pattern ewe with white blaze (her light phase self lamb stands behind her), Hirta
Dark self ram lamb with unusual white markings, Hirta
Dark phase ewe with white mottled area on her body, Hirta Paddy Zakaria photo