[ericthered]

Combat Physiology is a thing -- where are all the good places to hit someone (or something). But its probably either a perk, as mentioned, or an easy skill. And an easy skill covering more than one creature.

If I was going to try and encourage that type of skill I'd certainly slightly nerf combat without it and give bonuses if you have it. I probably wouldn't bother unless it was a game with lots of exotic creatures: bug hunt, a fairly wacky DF, Old Man's War and so forth.

I actually had another thought: Physiology uses the word species, but I suspect that it actually works better on the level of Genus or family. Those are admittedly scientific terms, but how much difference is their really between a lion and a tiger? Or various forms of deer? those differences can probably be subsumed in familiarities.

Of course, the skill is almost always used for humans, which are the sole member of our genus and family. In a setting where we are not, you're likely dealing with fantasy, and fantasy writers and fond of doing things like giving dwarves two livers and other things that would make taxonomists either very frustrated or very excited.