Are dolphins the most intelligent animals?

Their big brains and the complex structure of the cerebral cortex long led zoologists to believe that dolphins must be extremely intelligent. Members of the toothed-whale species can learn movement sequences very quickly. But their brain isn’t useful for anything much harder than that and they are outshone by both pigeons and rats in problem-solving and memory exercises. Scientists suspect that because the dolphin’s brain contains more supportive tissue and has relatively few nerve cells, they prefer to use their large brains for regulating body temperature instead of thinking.

Quick fact