Breeding grey alpacas by Elizabeth Paul. Photos courtesy of Arcadian Alpacas.
There are two pigment colours, yellow and black. The expression of both pigments across the animal is generally called agouti, and this produces the grizzled grey shade common to small wild animals such as rodents and marsupials. In large domestic animals agouti results in a more defined pattern, with the main body colour being reddish brown, produced by more intense yellow pigment, with black “points” ie muzzle, mane and tail, lower legs. This pattern is called bay in horses, and most fawn and all brown alpacas exhibit the same pattern. When analysing mating data I combine both fawn and brown under the heading Bay.
Grey In Alpacas
Grey and whitespotting genes are generally dominant alleles which produce an effect on top of the base colour. The appearance of grey fleece is not caused by a “grey” gene producing grey pigment, but usually by a diluting gene which alters the arrangement or amount of pigment within the fibre. This allows more light to pass though the fibre thus lightening the colour. Diluting genes are most effective on dark pigment, since diluting yellow colour only results in a lighter yellow.
There are at least two forms of grey in alpacas, the more common of which is what I call classic grey, where the alpaca is born with a grey coat and a white face, framed by a “bonnet” of its base colour, and a white neck. The appearance of the pigment granules in the “grey” fibre shows that they are clumped together and shifted over to one side of the fibre. This allows more light to pass through the fibre which visually softens the base colour to greyish tones.
A silvergrey alpaca is black, and a rosegrey alpaca is dark mahogany brown (ie dark bay) as the base colour. Classic grey on a fawn colour base may show up as a white faced fawn roan or rosegrey. The clumping effect of the grey gene also often produces blue or partial blue eyes in greys. Note again this is not” blue” pigment, it is simply the effect of clumping the black pigment together altering the light reflection.
The appearance of grey fleece is not caused by a “grey” gene producing grey pigment, but usually by a diluting gene which alters the arrangement or amount of pigment within the fibre