Bird brains, such as parrot and crows so that brain size is not everything. A crows brain is smaller than a chimps in overall size and body:brain ratio, yet cro

Bird brains, such as parrot and crows so that brain size is not everything. A crows brain is smaller than a chimps in overall size and body:brain ratio, yet crows show more complex social behavior, problem solving and tool use (despite not having hands). Bird's brains are much denser than mammals, so it's less size and more number of neurons, and the complexity of how these neurons are networked.