Beginning and ending with images of human children in bed, this gentle story describes where, when, how often and how long different animals sleep. Realistic paintings of particular species at rest fill three-quarters of each double-page spread. Each main idea is printed as a title; sidebars identify the species pictured and add more detail for interested listeners or readers. Beyond familiar species like lions, bats and bears, the author includes interestingly different examples: a New Zealand cricket that freezes solid, swifts that sleep while flying and parrotfish that make their own cocoons. Important terms, such as predator and prey, are introduced and explained in context. Animals are pictured naturalistically in their appropriate environments. The children reading themselves to sleep are African-American. The animal examples come from all parts of the world, reminding readers of the universality of this necessary activity. Both bedtime book and informational text, this appealing title ends with a short list of books and websites for further research. (Picture book/nonfiction. 4-7)