What Are Marine Mammals? Mammals are animals that breathe air
through lungs, are warm-blooded, have hair (at some time during
life), bear young alive, and suckle their young. Marine mammals
are a diverse group thought to have evolved from terrestrial
ancestors to aquatic life through a number of unique physical
adaptations. Representatives are found in every ocean, on every
continent, and in a variety of ecological roles, including
herbivores (manatees), filter feeders (baleen whales), and apex
predators (killer whales). In this website we present
information on three groups of Alaska marine mammals: cetaceans
(whales, dolphins, and porpoises), pinnipeds (seals, sea lions,
and walrus), and marine fissipeds (sea otter and polar bear).
Cetaceans and pinnipeds exhibit extraordinary anatomical and
physiological adaptations to a marine existence. Consider the
physical demands on a warm-blooded, air-breathing animal living
an amphibious or totally marine existence. Marine mammals have
adapted to the extreme tempera