“A common trend in the animal kingdom is that the sexes differ in size. People tend to assume this means males are larger, presumably because that’s what we find in our own species. Most of the time, however, it’s the opposite: Males are the midgets, and females the larger sex. This is the case with many insects and most spiders, as well as most fish, many frogs, and most birds of prey. It’s also the case with blue whales, which has the interesting implication that the largest individual animal on the planet is probably a female.”