A kolinsky sable is a weasel that lives in Siberia. Its tail has
the most wonderful hair on it: not only does it make the best brush
you can possibly have, ALL the hair falls out twice a year. There
are people who make their livings by going out in the woods and
picking up the big lumps of shed fur off the ground. (They have
to--they can't farm kolinsky sables because it stresses them out
too much, and the weasel relieves its stress by chewing the hair
off its tail.)