How do you define black fur?

I've been making a lion 'suit out of this really nice black glittery fur but how do I make definition in the fur so it's not just all one lump of black? For example, the line from the nose to lip.

Edit: I tried the different shade of fur method and I think it could work! Everything is still lying flat on the head so there's none of the groove under the nose (if I push on the fur the grey starts to disappear, so I left it on top) but what do you guys think?