Pinnipeds

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Pinnipeds

• Seals, sea lions and walruses

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Taxonomy

• Kingdom Animalia
• Phylum Chordata
• Subphylum Vertebrata
• Class Mammalia
• Order Pinnipedia
• Family Otariidae eared seals (fur seals,
  and sea lions)
• Family Phocidae true or earless seals
• Family Odobenidae walruses

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Mammalian characteristics

• Homeothermic constant temp.
• Mammary glands
• Hair
• Live birth placental connection
• Lungs

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Pinnipedia characteristics

• Streamlined
• More at home in water, but all come on land to
  breed and raise young
• Blubber most are found in cold water
• Natural predators killer whales, sharks, humans,
  polar bears
• Severely hunted, most species are stable
• Deep-diving physiological adaptations
• carnivores

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Eared seals

• Sea lions coarse coat of nothing but hairs
• Fur seals thick, dense under fur beneath the
  stiff, outer guard hairs. This is why they were
  valuable in the fur market.

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California Sea lion

• Used in zoos, shows, navy research

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Steller Sea lion

• Lives in the North Atlantic. Used to be
  extensively hunted.
• Slow to recover

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Steller sea Lion tearing apart a huge stingray
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Galapagos sea lion
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These sea lions are very trusting because they
are not exploited by humans
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South American Sea Lion

• Males are huge!

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True or earless seals

• Seals are usually found in cold climates
• Seals cant rotate either of their flippers,
  therefore, they are not able to walk on land.
  They are slow and clumsy on land.
• Most of them are solitary, the exception is the
  social elephant seal
• Describe them more as a stuffed sausage ,
  rather than sleek and fast

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Seal anatomy
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Harp seal

• Arctic
• White, furry pups hunted during first few weeks
  for their coat.
• Clubbing in Canada caused protests, bans on fur.
  Canada banned fur sales for awhile, then resumed
  in 2004.
• Now allowing up to 300,000 / yr. to be taken

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Clubbing of the harp seal pups
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The controversy is on again !
The anti-sealing campaign put pressure on Canada
to end the hunt.
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Clubbing of the babies
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Crabeater seal

• Antarctic
• Eats krill with sieve-like teeth

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Elephant seal

• Huge proboscis on males
• Largest seal bull up to 20 ft. 4 ton
• Hunted almost to extinction for blubber (100
  individuals)
• Now common along Calif. And Baja
• Only seal with a harem, most are solitary
• Males are very aggressive and territorial toward
  other males.

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Elephant seals Northern and southern populations
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Harbor seal

• Common in zoos
• Atlantic and Pacific coasts
• Spotted, large individual variation

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Mediterranean monk seal

• One of the few found in warm areas
• The most endangered now

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Hawaiian monk seal

• Another warm region seal
• Very endangered now ( appro. 1,200)

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Leopard seal

• Antarctic
• Large, ugly
• Predator to crab-eater seal pups and penguins.

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Weddell Seal

• Antarctic
• Used for research on diving physiology
• Scientist attach instruments to their backs to
  record depths, pressure, temp. time down etc.

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Eared seals compared to Earless

• External ears
• Long necks
• Posterior flippers rotate forward
• Anterior flippers rotate back
• Flippers have no nails
• Social
• Noisy, barking

• No external ears
• Short, fat necks
• Posterior flippers cant rotate forward
• Anterior flippers cant rotate back
• 5 toes, sharp nails
• Solitary (most)
• Snorts, grunts

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Walrus

• Tusks used to haul out on the ice, and defense
• Whiskers, called vibrissae, used as feelers
• Suck up benthic invertebrates such as clams.
• Very social

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Reproduction in Pinnipeds

• Breed and raise pups on ice or land
• Called bulls, cows, and pups
• Typically the pups grow quicker and become
  independent faster closer to poles.

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Seal Reproduction

• Often female gives birth alone. Male doesnt see
  the pup.
• Typically monogamous / may remain together
• High fat milk makes them grow quickly, adaptation
  to short breeding season. May be weaned in days
  to couple of weeks.

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Sea lions, Fur seals, Elephant seals

• Sexual dimorphism males larger
• Males defend territories, constant fighting
• Harems of up to 50 females
• Only the best males breed ( ensures survival of
  the species)
• Young and inferior males ? bachelor groups
• Females care for pups, nurse for long periods,
  teach them to swim

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The males arrive first and fight!
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The pups arrive
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Delayed implantation

• Ovulation occurs few days after giving birth.
• Only come on land once per year. Gestation
  period is less than a year.
• Therefore, they have delayed implantation in
  which the embryo is dormant up to 4mo.

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Diving Physiology

• Several go for 45 min.
• Exhale to reduce buoyancy
• Metabolism slows by 20
• Heart rate decreases, conserves oxygen
• Blood shunted to vital organs (brain, heart)
• Deepest divers Weddell seal 1,968 ft. / 70 min.
• Elephant seals typically 2,300 ft. Record is
  a female to 4, 125 ft.

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MMPA

• Marine Mammal Protection Act of 1972 protects
  all marine mammals and restricts sale of their
  products in the U.S.