Mammals

From whales and dolphins to seals and sea otters. Marine mammals are defined by their reliance on the ocean for food, along with mammalian characteristics such as hair and mammary glands. 

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In the late 1990's, researchers at the Woods Hole Oceanographic Institution (WHOI) invented the D-Tag —a radio device that can be attached by suction cups to a whale's back. Using a tiny underwater microphone,...
Killer whales ( Orcinus orca ) are master hunters, using speed, camouflage, and...
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In honor of Mother's Day, the Citizens of the Sea blog salutes ocean-going...
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How do we know where ocean animals swim day and night? Scientists are getting...

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The North Atlantic right whale is one of the world's largest animals, but scientists estimate that fewer than 450 remain. In the past, they were hunted for their oil and baleen; now they get tangled up in fishing lines, which...
A 2010 study of IUCN's Red List of Threatened Species found that one-fifth...
The ocean sustains land animals besides humans. Here, a fox looks for a meal...

DIVE DEEPER

The threat that climate change poses to polar bears has received a lot of attention, but they are not the only Arctic...
Whale baleen, the stiff bristly mouthparts that sieve small prey from the water, was strong yet flexible, and was used to provide structure in many human products, including umbrellas, corsets, and...
Three distinct types of killer whale, or orcas, can be found in the Antarctic, each with a different habitat and diet preference. One type of orca preys almost exclusively on the Antarctic minke...
A crew works on creating a life-size, meticulously detailed model of the North Atlantic right whale Phoenix—the “ambassador” of the Smithsonian’s Sant Ocean Hall in the National Museum of Natural...
Arctic scientists study a range of marine animals – from large species like polar bears to the microscopic, like phytoplankton. The amount of phytoplankton at different depths can tell us about the...
“At night, spotted dolphins move offshore into the Gulf Stream’s deep waters in search of squid.” -- Nature's Best photographer, Andrew Sallmon. See more beautiful ocean photos in our slideshow of...
The evolution of whales represents one of the great stories in macroevolution. It's a narrative that has mostly benefitted from an extraordinary series of fossils recovered from rocks around the...
A polar bear ( Ursus maritimus) in Churchill Wildlife Management Area in Manitoba, Canada smelling the scent of humans while waiting for sea ice to form on of the Hudson Bay. There are several human...
Phoenix, the North Atlantic right whale whose replica hangs from the ceiling of the Sant Ocean Hall at the National Museum of Natural History, was sighted with a calf off of Amelia Island in Florida...
A right whale opens its mouth wide, revealing huge plates of baleen hanging from its upper jaw. There are between 200 and 270 baleen plates on each side of a right whale's upper jaw. They work like a...
"Wild manatees in Belize are not used to humans. Living miles offshore in mangroves, they remain shy and elusive. After weeks searching and waiting for an opportunity to photograph them, I was...
Polar bears are threatened by the loss of sea ice in the Arctic . They walk for miles on the ice shelves to access different parts of the sea to hunt seals and other food. But as the ice melts as the...
Bottlenose dolphins ( Tursiops truncatus ) are very social animals, and often travel and hunt in groups called pods. The most common is a nursery group of 5-20 dolphins made up of females and their...
Ari Friedlaender, a research scientist at the Duke University Marine Lab, tags a blue whale.
Phoenix swimming with her calf in February 2007 in the Southeast calving grounds off the coasts of Georgia and Florida. Researchers track these highly endangered whales (there are only about 450 of...
A white scar on Phoenix’s lip (at right) was caused by her entanglement with a fishing line. Learn more about the life of Phoenix, an actual North Atlantic right whale, in the Tale of a whale photo...
In the episode of One Species at a Time , writer Karen Romano Young takes an icebreaker to Barrow, Alaska, to join in the festival of Naluqatak and learn about the intimate relationship between the...
Phoenix swims in George’s Bank, off the coast of New England, on March 13, 2009. More about whales can be found in our Tale of a whale featured story .
The bowhead whale has a massive, bow-shaped skull to break through thick Arctic ice, and more blubber than any other whale.
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