“Why All the Fuss about Sex?” wonders Michael Ryan. He wonders enough to make it the title of the first chapter of his new book, A Taste for the Beautiful. One would be forgiven for thinking it would be a short chapter—consisting of the single word “duh”—but Ryan is a zoologist who studies evolution and animal behavior. So he has a slightly different take.

“I have a unique perspective to offer on these issues,” he writes, “as I have spent the past 40 years studying the sexual behavior of a tiny, bumpy frog in Central America.”

It’s not that he has a fetish; it’s that he uses these túngara frogs—along with bowerbirds, howler monkeys, fireflies, peacock spiders, collared lizards, corn borer moths, hairy caterpillars, surf perches, and bee orchids—to demonstrate how beauty, and the appreciation of it, may have evolved in animals. Like us.