What is the cleverest animal?

Many people have raised dogs, which have been familiar with all kinds of human.
Why have people raised dogs for a long time?

That’s why dogs are one of the clever animals. Most know that how wonderful dogs are clever. I strongly believe that dogs are the cleverest animal in the world. After training, dogs can conduct cleverer actions than in past years. It seems that dogs understand human orders as well as sometimes behave like people.

We have seen and heard many clever dogs around in the world around us. For instance, although other animals might evacuate excrement here and there, dogs never do fundamental training. In addition, when a person, who has raised one dog in his house, moved into another place without his dog, the dog found out owner’s scent to back to the house. After all, he could find out owner’s house away from hundreds miles. Any animal can not remember a cold scent. It shows that dogs can save and distinguish information in brain.
By reason of above, dogs have been used by human in the field of stock breeding to protect other animals such as chickens, cow, and then pigs against ferocious beasts and hunting. There is no doubt that dogs have higher intellectual power than other animals.

Except above reasons, there are many reasons to prove that dogs are clever. I think what the lord of all creation select is the most important reason. If dogs are not clever, have human used them?