Sprung off something I read, on these boards, regarding the Death Realm and corpses. Also, working to make the game mechanics more consistent with their Settings. Frankly, I hadn't really bothered to consider such a thing for PlaneShift yet.
When any animal dies, sentient or otherwise, let's say that its soul — whatever magic animates it — goes to the Death Realm and brings its body. Sentients are able to bring their immediate possessions with them, but nonsentients lack the wherewithal to do so.
Thus, there are no corpses in-game.
From in the DR, the animal can either manage to return to the Life Realm or Vital Realm or whatever, or it remains in the DR. Or, it experiences “true death” in the DR, which occurs either immediately or gradually.
If it experiences such “true death”, then the material of its body is somehow recycled to the lands of the living again — via magic working in reverse of whatever pulled its corpse towards the DR.