Marine mammals

Marine mammals are found in every ocean.

There are over 70 different species of cetaceans that spend their whole lives in water. Cetaceans are categorized into two main groups: baleen whales (mysticetes) and toothed whales (odontocetes). Pinnipeds are carnivores that use flippers for movement on land and in the water. Their name comes from the suborder called pinnipedia which means "fin-footed." Pinnipeds spend the majority of their lives swimming and eating in water and come onto land or ice floes to bear their young, sunbathe, and molt. Like cetaceans, sirenians also spend their whole lives in water. "Sirenia" comes from the word "siren." "Sirens" are legendary Greek sea beauties who lured sailors into the sea. We think historic mermaid sightings were actually sirenians, not the mythical half women, half fish. The marine fissipedsoffsite link are unique because they are considered marine mammals, but spend most of their time on land and only part of the time in the water, mainly to hunt for their food.

Springer was seen with her newborn calf on the 4th of July along British Columbia's central coast.
Springer seen with new calf
She’s back with a newborn by her side! Springer, an orphaned killer whale calf rescued from Puget Sound and returned to her family in Canada in 2002, was sighted with her new calf — adding to her already remarkable story....

They also represent a variety of ecological roles, including herbivores (manatees), filter feeders (baleen whales), and top predators (killer whales); but what is a marine mammal? Marine mammals meet the five characteristics of a mammal. They breathe air through lungs, are warm-blooded, have hair (at some time during life), bear live young, and produce milk to nurse their young. They are a diverse group of mammals with unique physical adaptations allowing them to thrive in the marine environment with extreme temperatures, depths, pressure, and darkness.

A response team led by the Hawaiian Islands Humpback Whale National Marine Sanctuary, working closely with NOAA Fisheries, successfully rescued an entangled humpback whale in 2013. Rescuers managed to cut away only 40 feet of trailing line on the first day of the response. But they also attached a satellite tag into the trailing gear, allowing them to relocate the animal a few days later. During the second attempt, they removed an additional 200 feet of line and two buoys, completing the rescue.
How to disentangle a tangled up whale
Every year, dozens of whales become entangled in fishing gear off the U.S. Atlantic coast. The Atlantic Large Whale Disentanglement Network works to save them...

Threats and protection

Threats to marine mammals are largely from human impacts, including accidental capture in fishing gear, habitat destruction, poaching, pollution, harassment, and ship strikes. All marine mammals in waters of the United States are protected under the Marine Mammal Protection Act (MMPA), which includes over 60 marine mammal species. NOAA's National Marine Fisheries Service works in collaboration with several partners to protect these species. Citizens can also help protect marine mammals by showing proper ocean etiquette. Admire them from a distance and never touch, feed, harm, or swim with a marine mammal.

Pygmy killer whale in foreground with Research Vessel Ocean Starr in background.
Marine mammal survey spots unusual species
An on-going NOAA Fisheries marine mammal and ecosystem survey off the West Coast has sighted several surprising species of tropical cetaceans and birds, never before documented so far north...


The education resources in this collection provide educators and students opportunities to explore the adaptations, population dynamics, ecology, threats, behaviors, and anatomy of marine mammals. This collection includes several videos, lessons, activities, games, data resources, and career profiles to help students better understand the biology of marine mammals as well as their role in protecting these species.