What is a Marine Mammal? (The Science of Living Things)

Whales, manatees, seals, dolphins, and sea otters are just some of the many mammals that have evolved over time in order to survive in the water. From Arctic waters to tropical seas, vivid photographs and surprising facts about these salt water mammals reveal:

-- how these air breathing creatures have adapted to the water
-- their underwater senses
-- what they eat and how they raise their young
-- cetaceans, pinnipeds, sea otters, sirenians, and polar bears
-- marine zoos
-- the dangers of pollution, commercial fishing, and poachers