Marine Mammals

• Endothermic
• Most have some form of insulation (blubber, fur, hair)
• Live birth, young fed milk via mammary glands
• Great ability to dive
  • Binocular vision
  • Expels every ounce of air in their lungs (fully collapses their lungs)
  • Twice as many red blood cells, or hemoglobin
  • IRBC = 390 Million
  • Muscle contains more myoglobin than regular mammals
  • Can dive for 45 minutes to 2+ hours
  • Shunts blood: delivers blood to specific parts of the body, like the brain, heart, and muscles
  • Bradycardia = the process by which your heart rate drops dramatically
  • Dropping heart rate to 3-5bpm

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Sea Otters

• No blubber, but they have very thick fur
• The thickest fur in the animal kingdom
  • 100,000 hairs in a cm²
• This prevents their skin from touching cold water
• Increased/higher metabolic rate → They must eat 25-30% of their body weight everyday
• Are able to use tools

Polar Bears

• Only found/live in the Arctic
• Very good swimmers
  • Webbed paws
• Skin is very dark, nearly black
  • Will absorb more heat from the sun
• Fur/hair is hollow
  • Traces of photosynthetic organisms that rely on the sun are in the fur that allows heat to travel to the dark skin, keeping them warm even in cold climates

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Manatees vs. Dugongs

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Seals, Sea Lions, and Walruses

Cetaceans

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Toothed Whales: Odontoceti

• One blowhole
• Teeth
• Round heads

Baleen whales: Mysticeti

• 2 blowholes
• Baleen
• Flat, telescopic heads

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• Both organisms have the ability to create echolocation, but the vast majority are the odontocetes

  

• Ignore that this whale is evil but in order for them to echolocate:

  • The blowhole must be closed
  • The flaps vibrate behind the melon filled with oil
  • The waves are sent out and they return to the whale
  • The whale can then identify shape, distance, and size
  • The energy is picked up by their lower jaw

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