Crows understand human faces, express complicated ideas, and plan.
Chimps are our closest animal relatives, therefore it's hardly surprise they're intelligent.
Elephants have the most intelligent brains. Elephants have as many neurons as humans in their cortex.
Primate like humans and chimps. Koko the gorilla learned sign language and had a pet cat.
Cetaceans are as intellectual as birds and monkeys. Mammals include dolphins and whales.
Pigs solve mazes, grasp emotions and symbolic language. Piglets understand reflection before humans.
Three-fifths of the octopus' neurons are in its arms.
Parrots are as smart as children. These birds grasp problems and cause-and-effect.
Man's best friend is smart and social. Dogs understand emotions, empathy, and symbolism.