Marine Mammals

What is a Mammal? Mammals have a 4 chambered heart. Mammals are warm-blooded. They have hair/fur. Have mammary glands. Give birth to live young.

Pinnepeds Pinnepeds are marine mammals that have flippers and blubber, that need to breed on land. Seals, Walruses, and Sea Lions all belong to this Order. Pinnepeds live in cold water, they have a thick layer of blubber to keep them warm. They are mostly carnivores and feed on squid and fish. They have streamlined bodies and are excellent swimmers. Seals are the largest group of pinnepeds.

Seals Seals have rear flippers. They move forward by pulling themselves along the ground. Seals do not have ear flaps. They are hunted for their fur and are protected by the Marine Mammal Protection Act of 1972. There are approximately 19 species of Seals.

Sea Lions Are also called Eared Seals, because they have external ear flaps. They can move their rear flippers forward to walk. They are graceful and agile swimmers. These are the “guys” that you see at Marine World or an Aquarium doing neat tricks and they also work for the US Navy! At one time they were hunted for their fur, but are now protected by the MMPA of 1972.

Walruses Have large protruding tusks for digging up mollusks. They love to eat clams! They have stiff whiskers for feeling around on the ocean floor. They are the largest Pinneped, weighing up to 2700 lbs!

Sea Otters Are members of the Order Carnivora. They are the smallest Marine Mammal, weighing 60-80 lbs. They lack a layer of blubber, and make up for it by trapping air in their dense fur. They were slaughtered to the brink of extinction for their beautiful fur, but became protected by an international agreement in 1911. They are playful, and intelligent. They eat mostly shell fish and spend most of the day maintaining their fur.

Polar Bears Is the second member of the order Carnivora that is a Marine Mammal. They are semi aquatic, and inhabit both the land and the sea. They feed primarily on seals. They have recently been put on the endangered species list because of loss of habitat due to global warming.

Cetaceans This is the largest group of Marine Mammals, consisting of Whales , Dolphins, and Porpoises. These, of all the Marine Mammals, have made the most complete transition to aquatic life. These animals spend their entire lives in the water. They are streamlined, and look remarkably fish-like. They breathe air through lungs and have nostrils on the tops of their heads called a blowhole (some single, some double).

There are more than 90 species of Cetaceans. They are divided into two groups: toothed Whales (which includes Dolphins and Porpoises), and toothless Whales which have a Baleen. Instead of teeth, Baleen Whales have rows of flexible, fibrous plates, that hang from the upper jaws (called a Baleen). These are used to filter out plankton and tiny organisms from the water. Baleen Whales are the largest animals to ever have lived on this planet. There are 13 species of Baleen Whales, the Blue Whale being the largest at up to 110 ft. long, and up to 200 tons.

The remaining 80 species of Cetaceans are toothed Whales. Their teeth are adapted for a diet of squid, fish, and other prey. Teeth are used to catch and hold prey, not to chew it. The largest of the toothed Whales is the Sperm Whale, made famous by the novel “Moby Dick”. Killer Whales, or Orcas, are beautiful black and white Whales that are predators, eating seal, penguins, sea otters, and fish. They are more common in cold water, but are found round the world.

Dolphins are highly intelligent creatures, and can be easily trained.. They are very playful, and have been known to “escort” ships for miles at a time. Porpoises are really blunt nosed smaller Whales. Dolphins, Porpoises, and Whales travel in groups called Pods. They are protected by the MMPA of 1972, but are still hunted. The Japanese, and Norwegian fishing Industries have been illegally whaling under false pretenses ( scientific whaling). It is common for Cetaceans to get caught in fishing nets meant for other species.

Communication One way Cetaceans communicate is through Echolocation. They release tiny bubbles through their blowholes and make clicking sounds to communicate with each other and determine distances, and warn others about danger. This is natures version of Sonar. The Melon (fatty structure on the top of their heads) focuses and directs these sound waves. Cetaceans produce a rich variety of sounds tha are associated with different moods, sexual signaling, feeding, alarms……

Breaching When Whales leap in the air and loudly crash on the surface of the water. This can be a warning signal, getting rid of external parasites, fun, or a way of scanning the surface.

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