MARINEMAMMAL
Marine mammal
Marine mammals, which include seals, whales, dolphins, and walruses, form a diverse group of 128 species that rely on the ocean for their existence. They do not represent a distinct biological grouping, but rather are unified by their reliance on the marine environment for feeding. The level of dependence on the marine environment for existence varies considerably with species. For example, dolphins and whales are completely dependent on the marine environment for all stages of their life, whereas seals feed in the ocean, but breed on land. Marine mammals can be subdivided into four recognised groups; cetaceans, pinnipeds, sirenians, and fissipeds, which are the ...The above text is a snippet from Wikipedia: Marine mammal
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