underwool

The thermal properties of reindeer fur are legendary: it has a thick felty layer of underwool and long thick guard hairs that appear to be hollow, but on inspection under a microscope each hair turns out to have a core of vacuolated, keratinised cells.

Its hair is more like that of a goat than a sheep, of a brownish gray colour, and with a dense coat of underwool.

The largest of rodents, it possesses a close underwool of bluish-brown hue, nearly an inch in depth, with coarse, bright, black or reddish-brown top hair, 3 in. long.

Underwool short and even, with a shade longer top hair.

Yellow underwool 1/3 in. deep, black top hair, 1� to 1� in. long, very fine and open in growth, and not close as in martens.