Marine mammals include some of the most fascinating animals on Earth. Large, majestic whales and stunning, playful dolphins have provided mysterious companionship to humans at sea for hundreds of years. These magical creatures, along with their equally fascinating relatives, the seals and sea lions, have developed a completely different set of adaptations from their terrestrial ancestors and relatives. Volume 4 of the HMW series provides complete accounts of all species and families in these important groups. Lavishly illustrate with colour photographs showing different behaviours of all or them, the text contains the latest up-to-date information on all families of sea mammals. Contents: Familia Trichechidae, Thomas O'Shea. Familia Dugongidae, Helene Marsh. Familia Phocidae, Brent Stewart. Familia Otariidae, Marc Webber. Familia Odobenidae, Brent Stewart. Familia Platanistidae, Gill Braulik. Familia Lipotidae, Brian Smith. Familia Ziphiidae, Colin MacLeod. Familia Iniidae, Vera da Silva. Familia Pontoporiidae, Eduardo Secchi. Familia Delphinidae, John Wang, Kimberly Riehl & Sarah Dungan. Familia Monodontidae, Pierre Richard. Familia Phocoenidae, Thomas Jefferson. Familia Physeteridae, Sarah Mesnick. Familia Kogiidae, Donald McAlpine. Familia Balaenidae, Barbara Curry & Robert Brownell. Familia Neobalaenidae, Catherine Kemper. Familia Eschrichtiidae, Steven Swartz. Familia Balaenopteridae, Thomas Deméré.