Betta fish are very intelligent. They have been known to be able to recognize their owners. There are even some Betta fish that can do tricks like pushing a tiny ball through a ring using their nose. This is something that most fish are incapable of.
Bears are considered by many wildlife biologists to be one of the most intelligent land animals of North America. They possess the largest and most convoluted brains relative to their size of any land mammal. In the animal kingdom, their intelligence compares with that of higher primates.
Higher intelligence is linked with higher rates of mental illness such as schizophrenia and bipolar disorder, causing the “mad scientist” stereotype to have ground in reality.
Scientists studied a parrot for 30 years and found he had the intelligence of a five-year-old human. He had a vocabulary of 150 words and could ask for a banana. If he was offered a nut instead, he would stare in silence, ask for the banana again, or take the nut and throw it at the researcher.
Cows enjoy solving problems and have been known to jump into the air excitedly when they finally crack a tough one.
Dogs will sometimes fake being sick to get attention.
A species of Indonesian parrot called Goffin’s cockatoo can solve complex mechanical puzzles.