After a fight with wolves, usually I remember which one was the leader. When I try to skin it, there is no option to do so, even after a thorough check (with animals in general, it is very hard to position yourself so as to get the skinning option anyway). When I relog to solve the problem, the leader corpse is gone.
It's not always the case (recently it happened in 3 out of 4 my fights with wolves), but it was confirmed by another forum member.