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
Saint Bathans mammal Saint Bathans mammal The Saint Bathans mammal is a currently unnamed extinct mammal from the Miocene of New Zealand. A member of the Saint Bathans Fauna, it is notable for being a late surviving "archaic" mammal species, neither a placental or marsupial, as well as for providing evidence that terrestrial mammals did in fact once live in Zealandia, in contrast with modern New Zealand, where bats are the only mammals in otherwise bird-dominated terrestrial faunas. The Saint Bathans mammal is currently represented by two specimens, MNZ S.40958 and MNZ S.42214, composed of a lower jaw fragment and a femur respectively.