Identifying the Strange Creature

What was the situation?

 Let's first have statements by 2 creatures - 

A: B is a lying monkey. I am human.

B: A is telling the truth.

If we assume B is telling the truth then A is also telling the truth. But A in statement says B is lying which contradicts our assumption. 

Hence, B must be lying. If B is lying then statement of B suggest that A is also must be lying. That mean 'B is lying monkey' part of statement made by A is too lie. Since we have deduced already B is lying, the lying statement of A suggests that B is not monkey. Hence B is the lying man!

Other lie spoken by A is that it is human. Hence A must be a lying monkey!