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
Jugulator (mammal) displayed these behaviours. "Jugulator" occurs in the mid-Cretaceous deposits of the Cedar Mountain Formation, where several of North America's more iconic dinosaurs like "Utahraptor" and "Cedarosaurus" occur. A large variety of mammal species are known from here as well, including other eutriconodonts like "Astroconodon" and "Corviconodon" as well as multituberculates like "Cedaromys" and "Janumys" and several therian mammals such as "Montanalestes" and "Atokatheridium". These diverse mammal faunas offer a transition from dominant taxa in the Early Cretaceous and the multituberculate and therian dominated laurasian mammalian faunas of the Late Cretaceous. Jugulator (mammal) Jugulator is a genus of extinct mammal from