Okay, just a quick idea that occurred to me:

Why do we not occasionally get scars from losing battles? If we get our asses whooped, it seems far more likely that our lion took damage that would result in scarring. The chance wouldn't be very high, but I think it would be a nice realistic touch perhaps.

Also, the idea of "unique" scars that you can only get from certain NCL types comes to mind. For example, puncture type wounds from rhinos after being rammed into, and what not. These scars could be based on specific injuries that you might expect to see from picking a fight with certain animals.

Just two not-so-serious suggestions. When I get back from Mayo Clinic in a few days I'll expand upon this idea.