Some highly intelligent animals
Dolphins are well-known as intelligent animals. One thing that makes a dolphin very intelligent is the brain of the dolphin. The dolphin’s large brain is structured for awareness and emotion. Dolphins can detect emotion unlike any other animal that we know of so far. If you are swimming with a dolphin and your scared, the dolphin also knows you are scared. In fact, dolphin brains are more structurally complex than humans.
The bonobo is a close cousin to the chimpanzee, another famously intelligent animal. Extremely endangered, the bonobo is found only in central Africa. Like other great apes, bonobos have been taught to use sign language and symbols. National Geographic writes of "the bonobo Kanzi, for instance, carries his symbol-communication board with him so he can talk to his human researchers, and he has invented combinations of symbols to express his thoughts." These creatures are thought of as the closest animal to being as intellectual as a human.
Pigs may be the smartest domestic animals in the world. The New York Times reports on researchers who have found that domestic pigs can use mirror to find food and will try to deceive other pigs so they can hog more food. They also learn quickly and can do tricks ranging from jumping through hoops to playing video games with joysticks. Also when pigs get to hot they roll around in mud to cool off. This may sound gross but since pigs don't sweat its really the only way to keep cool on a hot summer day. Most animals would not even think to do that. Pigs are thought of as nasty, dumb animals but really their brain is very closely related to the brain of a human.