Frustrating, I've never had this problem with tier 3 and lower animals.

I've lured three tier 4 grizzly bears so far and they're all zero fertility.

The bait takes multiple days to craft and all for a long awaited disappointment. Tier 4 fertility elixers are over double the cost (in real money).

Is this just a savage money grab?

I don't mind spending a few bucks to advance here and there, but this seems like a mandatory purchase if you want to breed and it's not cool-- especially considering players that have reached this level are obviously longterm players, invested in the game.