What is the most clever animal in the world?

Every animal has its own talent. The chimpanzee is one of the best political/social animal. They have hierarchic structures what's comparable with that of humans.

But the best problem solving animal is the crow. The scientific researchers where looking if the animal can think over several steps. The crow can think more complex than a monkey!

The best environment adapting animal will probably a mouse or rat.

I don't think if there is any animal which can be pointed as most clever...