Marine mammal Marine mammal Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence. They include animals such as seals, whales, manatees, sea otters and polar bears. They do not represent a distinct taxon or systematic grouping, but rather have a polyphyletic relation due to convergent evolution, as in they do not have an immediate common ancestor. They are also unified by their reliance on the marine environment for feeding. Marine mammal adaptation to an aquatic lifestyle varies considerably between species. Both cetaceans and sirenians are fully aquatic and therefore are obligate water dwellers. Seals
Marine mammal park and Aurora, Ohio (which has since closed down). Many animal welfare groups, such as the WSPA, consider keeping whales and dolphins in captivity a form of abuse. The main argument is that whales and dolphins do not have enough freedom of movement within their artificial environments. The existence of marine mammal parks is thus very controversially discussed. Although sizable pools for whales and dolphins require an extraordinarily technical and financial expenditure and are usually nearly impossible to provide and maintain, many marine mammal parks endeavour to improve the conditions of captivity and attempt to engage in public education as well