Walker's Marine Mammals of the World
A comprehensive handbook of all living and recently extinct mammals in the orders Pinnipedia (seals, sea lions, walrus), Cetacea (whales, dolphins, porpoises), and Sirenia (dugong, sea cow, manatees), plus the polar bear and the two salt-water otters... There are numerous illustrations, mostly black-and-white photographs, and extensive citations to the primary literature. The treatment is scientifically rigorous.(American Reference Books Annual)