Coyotes rubbing.

[tikka250]

Was going to post this in the other thread but figured it warranted a new one.
Guys are always talking about coyotes being "rubbed" or the fur is "rubbing off" does this mean coyotes are physically finding a tree or scratching stick in -30 and rubbing off protective gaurd hairs?
My understanding of the reason for fur quality degeneration in the hips and rump was from coyotes lying down to sleep and when they rise a portion of fur gets stuck to the snow/ice.
I know if I shoot a coyote then leave him in the snow I run the risk of the body temps melting the snow a bit and gaurd hairs sticking to that snow/ice layer and pulling out when I pick it up.