Marine Mammals Quiz

Marine Mammals

• A marine mammal is a mammal living in a marine or aquatic environment, obtaining most of its food there.
• Dolphins, whales, and porpoises possess hair around their mouths early in life, which usually disappears.
• Seals, sea lions, walruses, sea otters, polar bears, and manatees are considered marine mammals meeting five specific criteria.
• There are four general types, including Cetaceans - whales, dolphins, and porpoises.
• Pinnipeds - seals, sea lions, and walruses.
• Sirenians - dugongs and manatees.
• Other/Carnivores - sea otters and polar bears.

Defining Features of Mammals

• Mammals have lungs and breathe air.
• They are warm-blooded, maintaining a constant body temperature.
• Most give birth to live young, with exceptions like Monotremes (duckbill platypus and echidna) who lay eggs.
• Produce milk for their young.
• Possess hair at some point in their lives (though some marine mammals lose it).

Echolocation

• Many marine mammal species use echolocation (sonar) for underwater navigation and hunting.
• A single blowhole and a wide throat are often features to accommodate large prey.

Toothed Whales

• Toothed whales include families like Ziphiidae (beaked and bottlenose whales) and Physeteridae (sperm whales).
• The white whale in Melville's Moby-Dick is actually an albino sperm whale, not a beluga.

Baleen Whales

• Baleen whales use their mouth as a giant strainer, with bony plates (baleen) hanging vertically.
• The spaces between the plates allow water to pass through but trap food particles.
• Whales swim through schools of fish with their mouths open, expanding their throat to take in both fish and water.
• They then push the water out, trapping the fish against the baleen plates for swallowing.
• Toothless whales are large (typically over 10 meters long), filter feeders, and lack teeth but have brushlike baleen sheets instead.

Specific Marine Mammals

• Walruses: Live in the Arctic, spending time in the water or on ice floes. Blubber layer over 6 inches thick.
• Manatees: Aquatic mammals called sea cows, known to prefer warm water, and being plant eaters.
• Dugongs: Live in shallow tropical seas; have pointed tails and tusk-like teeth. They usually travel in small groups.
• Sea Otters: Notably the only marine mammal species using tools for foraging.
• Polar Bears: Considered marine mammals due to their proficiency in swimming and hunting on sea ice. Have an estimated population of 21,000-28,000 animals. Polar bear males are 2-3 times the size of females.