Marine mammals are a diverse group of animals, globally accounting to 119 species. They include cetaceans (whales, dolphins, and porpoises), sirenians (manatees and dugong), pinnipeds (true seals, eared seals and walrus), a few otters (the sea otter and marine otter) and the polar bear (usually grouped with the marine mammals). 

Marine mammals have the same characteristics as all other mammals, but they have adapted to living all or part of their life in the ocean. To keep warm in the ocean, most of them depend on a thick layer of blubber (or fat). They have streamlined bodies to help them swim faster. Many species can stay under water for a long time, but must come to the surface to breathe. To be able to stay under water for long periods, they store extra oxygen in their muscles and blood. They also have more blood than land mammals in proportion to their body sizes, can direct their blood flow to only their vital organs (such as heart and lungs), and can slow their heartbeat down so as to use less oxygen in a dive.

In India, 31 species of marine mammals (30 species of Cetacea and one species of Sirenia) are documented accounting to one fourths of the world’s marine mammalian fauna and almost 8% of the total Indian mammalian fauna.

 

Marine mammals sighted or recorded along the coast of Gujarat are: