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Northern Elephant Seals Factoids

Northern Elephant Seals Factoids. Taxonomy. Class: Mammalia Order: Pinnipedia Family: Phocidae Genus / Species: Mirounga angustirostris. Diving. Can dive to more than 5000 feet (average 1000 – 2000) 2nd deepest diving animal in the ocean Sperm whale can dive more than 1-1/2 miles

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Northern Elephant Seals Factoids

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  1. NorthernElephant Seals Factoids (C) 2008 California State Parks

  2. Taxonomy • Class: Mammalia • Order: Pinnipedia • Family: Phocidae • Genus / Species: Mirounga angustirostris (C) 2008 California State Parks

  3. Diving • Can dive to more than 5000 feet (average 1000 – 2000) • 2nd deepest diving animal in the ocean • Sperm whale can dive more than 1-1/2 miles • Average dive: 20 minutes • Longest known dive: 2 hours • Less than 5 minutes on surface between dives • Swim 10 – 15 mph (C) 2008 California State Parks

  4. Breeding, Birth & Growth • First males arrive December • First females late December • Gives birth 3 – 6 days later • Gestation 7 months but… • Delayed implantation  5 months (C) 2008 California State Parks

  5. Breeding, Birth & Growth • Females reach sexual maturity at 2 years old • Begin giving birth at 4 years old • Males reach sexual maturity at 6 or 7 • Males normally mate at 9 or 10 (C) 2008 California State Parks

  6. Breeding, Birth & Growth • Breeding season • December through mid-March • Average harem: 20 females (C) 2008 California State Parks

  7. Breeding, Birth & Growth • Females come into heat 19 days after giving birth • Receptive only 4 days (C) 2008 California State Parks

  8. Breeding, Birth & Growth • 2/3 of males don’t breed • Milk is 54.5% fat • Richer than any other mammal • Adults may lose 50% of body weight during breeding season (C) 2008 California State Parks

  9. Molt • Molting • Females: April / May • Young males: May / June • Adult males: July / August • Stay in muddy water, beach • “Catastrophic” molt (C) 2008 California State Parks

  10. Annual Cycle - Male • Life span: 14 years • Maturity: 9 years old • 8 months at sea • 4 months post breeding • 4 months post molt • On land • 3+ months for breeding • 3-4 weeks for molt (C) 2008 California State Parks

  11. Annual Cycle - Female • Life span: 20 years • Maturity: 2-4 years old • 10 months at sea • 2 months post breeding • 8 months post molt • On land • 5 weeks for breeding • 3-4 weeks for molt (C) 2008 California State Parks

  12. Annual Cycle - Juvenile 10 months at sea • 5 months post breeding • 5 months post-fall haul-out • On land • 1 month for breeding • 1 month for post-fall haul-out (C) 2008 California State Parks

  13. Annual Cycle - Weaners • 5 months at sea • Leave beach 3-1/2 months old • Return for fall haul-out (C) 2008 California State Parks

  14. Time Line • November • Sub-adult males haul-out • Mature males begin to arrive • December • Mature males arrive • Females arrive • First births mid-month (C) 2008 California State Parks

  15. Time Line • January • Females continue arriving • Peak of births last 2 weeks • February • Births continue • Peak mating mid-month • Females leave (C) 2008 California State Parks

  16. Time Line • March • Last adults leave • Weaners learn to swim • April • Females return to molt • Juveniles return to molt (C) 2008 California State Parks

  17. Time Line • May • Females molt • Juveniles molt • June • Sub-adult males return to molt (C) 2008 California State Parks

  18. Time Line • July • Sub-adult males molt • Adult males molt • August • End of male molt (C) 2008 California State Parks

  19. Time Line • September • > 1 year olds haul-out • Juveniles haul-out • October • > 1 year olds haul-out • Juveniles haul-out (C) 2008 California State Parks

  20. Population Issues • 180,000 elephant seals • Population between 8 and 20 100 years ago • Hunted for their oil for lamps • Majority of hunting over 15 year period • Just like sperm whales (C) 2008 California State Parks

  21. Population Issues • The few remaining elephant seals started a new population and there are now 2 main colonies with other little ones here in Northern California (C) 2008 California State Parks

  22. Colonization • First on Ano Nuevo in 1955 • First pup 1961 • First at Piedras Blancas 25 November 1990 • First pup 1992 (C) 2008 California State Parks

  23. Colonies (C) 2008 California State Parks

  24. Males Females Migration (C) 2008 California State Parks

  25. Miscellaneous • Meaning of “Año Nuevo” • First seen by Spanish explorers on 3rd of January 1603 • Northern elephant seal is larger than Southern (C) 2008 California State Parks

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