Marine Mammals

Marine mammals are warm-blooded vertebrates (animals with a backbone) that bear live young and nourish them with milk as land mammals do, but that spend most or all of their lives in the ocean. They are broken into three groups that share similar adaptations to their aquatic life, but that have very different origins and life patterns.

Sirenians, the manatees and dugongs, are slow plant feeders found in warm, shallow coastal habitats. Pinnipeds, the seals, sea lions and walruses, bear young on land, but spend most of their time in the ocean. Cetaceans, the dolphins, porpoises and whales that spend all of their lives in the ocean, include both toothed species that are carnivorous predators, and filter-feeding baleen whales that consume huge quantities of tiny plankton. In size, marine mammals range from small seals and porpoises to the largest animal that has ever lived, the blue whale. Many cetaceans and pinnipeds dive to remarkable depths to feed, feats only recently discovered using digital tags that record the animals' movements, direction, and depth over time.

Marine mammals play important ecological roles as both predator (many hunt for fish) and as prey, both for sharks and other, larger marine mammals. Humans have also long hunted marine mammals for food and fur. Although hunting pressures have declined, marine mammals still suffer from low numbers and inadvertent human activities such as certain fishing methods, boating and shipping traffic, and increasing ocean noise.

WHOI scientists have conducted marine mammal research for decades, from making the first underwater recordings of marine mammal sounds in the 1940s, to the development of digital tracking tags and CT scanning methods. The WHOI Marine Mammal Center (MMC), fosters research on whales, dolphins, and seals, including their behavior, health, anatomy, and perception; methods to free entangled whales and the causes of strandings; and marine mammal populations' link to ocean conditions and plankton abundance. A particular focus is the endangered north Atlantic right whale, an animal that was hunted nearly to extinction and whose population only includes 300 to 400 individuals.

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News & Insights

Public Talk: Tracking Humpback Whales in Antarctica

Humpbacks migrate thousands of miles to their feeding ground in the Southern Ocean, yet nothing is known about how these whales find the krill that they consume. WHOI scientists joined an expedition aboard cruise ship Polar Latitudes to study the feeding habits of humpback whales on the Antarctic Peninsula. Using Zodiacs to get close enough to the whales to attach digital recording tags, his team logged whales’ diving and feeding behaviors. They also used fish-finding acoustic systems to correlate the location of the whales with their prey. Learn their findings from this research, accompanied by stunning images of Antarctica, humpback whales, and other sea life encountered in the majestic southern continent.

Can thermal cameras prevent ship strikes?

Researchers are testing the effectiveness of thermal IR cameras for automated whale detection to help prevent ship strikes in the narrow channels of British Columbia’s Gulf Islands.

Global Oceans and the Extinction Crisis

WHOI marine biologists Michael Moore and Andrea Bogomolni weigh in on a new United Nations science report suggesting that over one million species are at risk of extinction.

Untangling Impacts on Right Whales

Whale scientists look for new ways to mitigate whale entanglements in fishing lines

Seal Spy

Drones helps WHOI scientist measure the body mass of mother and pup seals during lactation

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From Oceanus Magazine

Scientists Reveal Secrets of Whales

Researchers have known for decades that whales create elaborate songs. But a new study has revealed a component of whale…

Scientists Reveal Secrets of Whales

Using drones to fly into the misty “blows” of exhaling humpback whales, scientists have found for the first time that…

Eavesdropping on Whales

WHOI scientist Mark Baumgartner has installed a mooring in New York waters that listens for whales and sends back alerts. The prototype advance-warning system could one day help reduce shipping collisions with whales.

Whale-safe Fishing Gear

WHOI engineers are developing a new kind of lobster trap buoy that could help keep whales from getting tangled in fishing gear.

How Would ‘On-Call’ Buoys Work?

WHOI engineers are developing a new kind of lobster trap buoy that could help keep whales from getting tangled in fishing gear.…


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