Did you know that a groundhog is really a type of squirrel? That squirrels control their body temperature with their tails? That most squirrels have yellow-tinted eye lenses that work like sunglasses to reduce glare? That tree squirrels can turn their hind feet completely around when climbing down a tree head-first? In Squirrels: The Animal Answer Guide, Richard W. Thorington Jr. and Katie Ferrell unveil the fascinating world of one of the "most watched" mammals on the planet.

The diversity of squirrels is astounding. There are 278 species that inhabit all continents except Antarctica and Australia—varying in size from the lumbering 18-pound gray marmot to the graceful pygmy flying squirrel that is smaller than most mice. In many parts of the world they readily share human habitats, joining us for lunch in a city park, raiding our bird feeders, and sneaking into college dorm rooms through open windows. Reviled as pests or loved as an endearing amusement, squirrels have played important roles in trade, literature, and mythology.

Thorington and Ferrell cover every aspect of this diverse animal family, from the first squirrels of 36 million years ago to the present day. With over one hundred photographs and an intuitive question-and-answer format, this authoritative and engaging guide sheds light on a common mammal that is anything but commonplace.

Richard W. Thorington, Jr. is a curator of mammals at the Smithsonian's National Museum of Natural History. He is the co-author of Squirrels of the World, published by Johns Hopkins University Press. For many years Katie Ferrell was Dr. Thorington's research assistant at the Smithsonian.