Marine mammal
A mammal adapted to life in the ocean or other marine environments. Marine mammals breathe air, give birth to live young, and nurse them with milk.
Mammal: A vertebrate whose females produce milk for their young and that typically has hair and maintains a stable body temperature. Marine mammals retain defining mammalian traits despite their aquatic adaptations.
Mammalian diving reflex: A set of physiological responses to submersion that conserves oxygen, including slowed heart rate and reduced blood flow to some tissues. It helps marine mammals extend dives by directing oxygen toward vital organs.
Marine mammal conservation: The study and practice of protecting marine mammal populations, habitats, and ecological functions. Conservation efforts address threats such as bycatch, pollution, and habitat loss.
Fish: Aquatic vertebrates that generally breathe through gills and lack mammary glands. Fish share the marine habitat but do not have the defining biology of mammals.
Cetacea: The order of aquatic mammals that includes whales, dolphins, and porpoises. Cetaceans are fully aquatic marine mammals, with bodies shaped for swimming.
Countercurrent exchange: A heat-transfer arrangement in which adjacent fluids flow in opposite directions, preserving heat or other substances. Some marine mammals use it in their limbs to limit heat loss to water.
Marine mammal stranding: An event in which a live marine mammal becomes stranded on shore or in shallow water, or a dead animal washes ashore. Strandings can prompt rescue, veterinary care, and scientific investigation.
Sea turtle: A marine reptile with a shell, lungs, and limbs adapted as flippers. Sea turtles breathe air but are reptiles, not mammals.
Pinniped: A group of fin-footed marine mammals that includes seals, sea lions, and walruses. Pinnipeds divide their lives between marine feeding and, often, land or ice.
Blubber: A thick layer of vascularized fat beneath the skin of many marine mammals. Blubber insulates against cold water and also stores energy.