Marine Mammals

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Marine Mammals

• November 27, 2007

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(No Transcript)
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Marine Mammals

• Viviparous
• Large and complex brain
• Endotherms
• Hair
• What are issues that marine mammals have to deal
  with?

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Order Pinnipedia

• Include seals, sea lions, and walruses
• Carnivores
• Streamlined bodies
• How do they keep warm?

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Seals

• 19 species
• Swim with rear flippers
• Include the largest pinniped
• Elephant Seals can reach 20 feet long and weigh
  3600 kg!

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Eared Seals

• Sea Lions - 5 species
• Fur Seals - 9 species

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Seals and Sea Lions

• What is the difference?

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Walrus

• 1 species
• Feeds on benthic invertebrates
• What are tusks for?

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Order Carnivora

• Sea Otter - 1 species
• Smallest marine mammal
• No blubber - how do they keep warm?
• Feed on benthic invertebrates
• Keystone predator of west coast kelp forests

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Order Carnivora
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Order Carnivora

• Polar Bears - 1 species
• Feed mostly on seals
• Semi-aquatic

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Order Sirenia

• Include Manatees, Dugongs, and Sea Cows
• Front flippers, no rear limbs
• Swim mostly with tail
• Thick layer of blubber
• Strictly herbivores
• Can reach 4.5 m, 600 kg

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Order Cetacea

• Includes whales, dolphins, porpoises
• Streamlined
• Blowhole on dorsal surface
• Blubber
• 2 groups
• Mysticeti (Baleen Whales)
• Odontoceti (Toothed Whales)

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Order Cetacea

• What is convergent evolution?

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Order Cetacea
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Order Cetacea

• Adaptations for Diving
• Muscles
• Heart rate
• Rib cage

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Order Cetacea

• Echolocation

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Mysticeti - Baleen Whales

• 11 species
• Baleen - made of keratin
• Attached to upper jaw

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Mysticeti - Baleen Whales
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Mysticeti - Baleen Whales
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Mysticeti - Baleen Whales
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Odontoceti - Toothed Whales

• 66 species

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Odontoceti - Toothed Whales

• Teeth adapted for different diets
• Only have 1 blowhole
• True toothed whales - 30 species
• Include Orca, Beluga, Narwhal, Pilot
• Most common in cold water
• Dolphins and Porpoises
• Distinctive beak
• Travel in pods

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Whaling

• Aboriginal whaling (Eskimos)
• Non-aboriginal whaling
• Began off New England in late 1600s
• Important Dates in Whaling History
• 1860s Explosive harpoon introduced
• Early 1900s Antarctic whales hunted
• 1946 IWC founded
• 1972 US Marine Mammal Protection Act
• 1985 IWC moratorium on commercial whaling
• Norway, Japan, Iceland still practice whaling
• IWC allows aboriginal whaling

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Whaling