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Notes on Marine Mammals
Marine Mammals Pinnipeds - They are predators that usually like to hunt for fish and squid
- Pinnepeds have blubber, which a thick layer of fat under the skin that helps keeps them warm.
- They have streamlined bodies and flippers used for swimming
- Most of them live in cold water, but pinnipeds have to breed on land.
- Examples of pinnipeds: seals, sea lions, walruses
Seals - Seals are the largest group of pinnipeds
- Seals swim by primarily using their rear flippers
- On land, their rear flippers don’t allow them to walk
- The seals, instead, have to use their front flippers
- The elephant seal is the largest pinniped
Sea lions - The difference between sea lions and true seals is that sea lions have external ears
- They can also use their rear flippers to walk, allowing them to use all four limbs for walking on land.
Walrus - Walruses have a pair of tusks projecting down from their mouth
Sea Otter - Sea otters have dense, dark brown fur and are carnivorous animals
- Some of their foods are: mussels, crabs, sea urchins and fishes.
- Sea otters lack blubber, but their fur keeps them insulated by the cold air.
- Sea otters are threatened species
- Hunters are attracted by their fur.
Polar Bear - Polar bears (Ursus maritimus) have dense, white fur and are semi-aquatic carnivorous animals
- They are found in the Arctic,
- They like to feed on seals
Sirenians - Also known as sea cows: manatees and dugongs
- Manatees and dugongs have no rear limbs
- These marine animals are strictly vegetarian
- They are hunted for their meat, skin and oil.
Manatees - There are three known species of manatees
- They are found in the Atlantic Ocean
Dugong - This is a strictly marine animal
- It lives near East Africa and certain regions of western Pacific islands.
Cetaceans are the largest group of marine mammals - They include: dolphins, whales and porpoises
- Cetaceans, which are mammals, have fish-like and streamline bodies
- Cetaceans need to breathe air, or else they will drown
- They are endothermic, produce milk, and have very small amount of hair.
- Cetaceans are divided into two groups: baleen and toothed.
Baleen Whales - Toothless whales
- They have baleen, which are keratinized plates that replace the teeth
- Baleen whales comprise of the largest types of whales
- Blue whales are the largest.
- They have two blowhole openings
Toothed Whales - They have teeth, but no baleen.
- Their food is swallowed, so they only use their teeth to catch prey.
- They have one blowhole opening
- Sperm whale is the largest toothed whale.
- Dolphins and Popoises are toothed whales.
- Dolphin:
- Dolphins like to travel in groups called pods, schools or herd.
- Dolphins have a characteristic beak or snout
- Dolphins are one of the most threatened cetaceans.
- Almost all toothed whales, including porpoises and dolphins, use echolocation
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