Birds have shown us a different way to shape an intelligent brain. Mammals use larger neurons to connect distant brain regions; birds keep their neurons small, close together, and locally connected and grow only a limited number of larger neurons to handle long-distance communication. In building powerful brains, says Herculano-Houzel, nature has two strategies: It can tinker with the number of neurons and their size, and also, it can change their distribution in different parts of the brain. In birds, nature uses both tactics—to brilliant effect.
