We humans pride ourselves on our big brains. We never seem to tire of bragging about how our supreme intelligence empowers us to lord over all other animals on the planet. Yet the biological facts don’t quite square with Homo sapiens’ arrogance. The fact is, people do not have the largest brains on the planet, either in absolute size or in proportion to body size. Whales, not people, have the biggest brains of any animal on earth.