I want to get this trophy, and it says to kill one of every species in the game. I've looked at my stats and it says that I have killed at least one of all of the animals. But the trophy still hasn't been achieved? Any idea as to why this is?
There are different reports about which animals are required for this trophy (see here and here). So you could check if you really got every animal. One important thing is that you have to kill each enemy either in offline or in online mode. Killing for example 50% in each mode will not unlock the trophy.