A muskox carries two coats. The outer guard hairs are coarse and can reach nearly to the ground, shedding wind and snow. Under them lies qiviut, a soft undercoat that the animal moults in large mats during spring, when it can be gathered from the tundra or combed from captive herds.
Measured fibre diameters generally fall in the low to mid teens of micrometres, placing qiviut alongside or below fine cashmere. It does not felt or shrink the way sheep wool does, and it is harvested in tiny quantities, a few kilograms per animal per year, which is why it commands very high prices.
The name misleads twice over. The muskox is not an ox but a member of the goat-antelope group, closer to takin, sheep and goats than to cattle. Claims that qiviut is a precise multiple warmer than sheep wool circulate widely but trace back to marketing rather than to published thermal testing.