Fudge tunnel. Dung funnel. Log chopper. Darwin's trumpet. Whatever you call it, your butt--yes, the one you're sitting on right now--is the fine-tuned product of millions of years of evolution. That's a fact--no ifs, a lot of butts.

In fact, inside your butt is a time vortex leading to the hole history of life on Earth, from the first butts that bubbled up from the primordial ooze to the hyper-specialized hunting machine you use to run fast, cushion your falls, and announce to the world that you were satisfied with your last meal.

Join The Crab Museum and illustrator Inga Ziemele in this hilarious kids' guide to evolution and the natural history of this noble body part. You'll come butt-to-butt with big butts, small butts, armored butts, stinky butts, multi-use butts, dino-butts, jet-engine butts, glow-in-the-dark buts, fossilized butts, and even an animal with 1,000 butts. Along the way, you'll learn the many surprising uses for butts that animals have found over the years, and even witness a terrible time in Earth's history when there were no butts at all.

Discover which animal poops cubes, how you have the biggest butt in the world (congratulations), and why deep down, you're nothing but a food tube.

Are you sitting comfortably? Yes, you are--because of your butt!