A fine introduction to the pinnipeds (three families of mammals that include true seals, fur seals, sea lions, and walruses), discussing their ancestry, anatomy, diet, life cycle, habits, and endangered status. Patent's text is full of odd facts of the sort dear to nature browsers: e.g., that "the male hooded seal has an enlargement of the nasal cavity that can be inflated, forming a black hood over the top of the head as big as two footballs"--or that radio transmitters, attached to elephant seals with epoxy glue, recorded a record dive of "more than four fifths of a mile into the ocean depths." Ever alert to the use of such curious facts to enrich understanding, Patent also describes the special adaptations that make such spectacular dives possible. An excellent science book, carefully researched, readable, and thoughtfully presented; extensively illustrated with appealing b&w photos. Table of scientific and common names; glossary; index.