Oh, the big ones and the small ones can't be distinguished from one another? That's not ideal.
Though I can tell you from the time I spend in the game, even when you use the original model of those creatures, it's hard to gauge if they are dead or not. I have definitely spend lots of time standing on rock, shooting frantically at something that turned out to be a corpse lateron.
That works? I tried it and somehow it did not do a thing for me. Maybe it was a bug.