OCEA 2000X Lecture Notes - Lecture 6: Marine Mammal, Ecoregion, Toothed Whale
31 Aug 2016
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Document Summary
Marine mammals share certain traits: air-breathing lungs, hair, live young, young nursed with milk from mammary glands, insulated, relatively long-lived and intelligence. Smallest marine mammal and most recently returned to the marine realm. Sirenia: the sea cows manatees and dugongs. Affected by human activities: boat strikes and loss of sea grass meadow feeding grounds. Walruses: benthic feeders, live in the northern hemisphere, both sexes have tusks, use vibrissae and tusks to probe the sediment for bivalve molluscs, frequent the ice edge. Sea lions and fur seals: external ears, flexible flippers, pelvis can rotate, longer necks, use front flippers for propulsion, more agile on land, form large colonies. Seals: no external ears, less flexible flippers, pelvis does not rotate, shorter necks, use rear flippers for propulsion, less agile on land, variety of sizes. Two major groups: odontocetes= toothed whales adaptable and intelligent pursuit predators. Use echolocation to detect prey: mysticetes = baleen whales feed on plankton and small nekton.
