A unique look at the many varying ways, times, and places that different animals sleep Mammals, insects, fish, and reptiles all get tired like us and need to sleep. This book illustrates vividly how and where they sleep in many different ways and at different times. Fish, snakes, and insects sleep with their eyes open. Birds sleep perched in trees without falling off. Bats sleep upside down for 20 hours a day. Sleeping whales and dolphins keep a part of their brains awake at all times so that they can go to the surface when they need air. Horses, elephants, zebras, and giraffes sleep standing up and for less than 4 hours a day.