For fans of accessible and fun popular science comes an exploration of evolution’s quirkiest puzzles and most enduring mysteries.  Why do cats live longer than dogs? Why do bees have yellow stripes? Why can we smell a skunk from a mile away? Such questions can be seen as puzzles about creatures' evolved traits. Besides triggering our curiosity, they focus our attention on beguiling designs that have been millions of years in the making. Indeed, looking at the living world through a Darwinian lens reveals its colossal depth in a way that's all too easy to miss in the age of endless distractions. You need only summon up your inner inquisitive 7-year-old to notice such puzzles, and to find yourself looking deeper while considering possible solutions.   In this lively book, science writer David Stipp ponders Darwinian puzzles about nine familiar creatures and things—bumblebees, dogs, sparrows, caffeine, earthworms, and sleep, among others—to show how rewarding it can be to look at nature in a deeper way. By revealing hidden depths of the ordinary, Why Rats Laugh and Jellyfish Sleep shows not only that fascinating intricacies lie just beneath the natural world's familiar surfaces, but that noticing them lets us make connections we didn't realize existed.  This is backyard biophilia at its most entertaining and enlightening.