Bird brains range in size from 0.13 gram for a Cuban emerald hummingbird to 46.19 grams for an emperor penguin. Tiny indeed next to the 7,800-gram brain of a sperm whale, but compared with animals of roughly the same size, not so small at all. The brain of a bantam bird weighs about ten times as much as the brain of a similar-sized lizard. Consider a bird’s brain relative to its body weight, and it comes out more like a mammal.
