Well, North American and European beavers have sacs located near their...well...the base of their tails. They produce a powerful scent when combined with the creature's urine, usually used to mark territory.

With a creature as large as a dire beaver, though, you could sicken or nauseate creatures.

Sorry if this grosses people out or anything. >> But, you know, this stuff is actually used in like, cologne and perfume.