Northern Elephant Seals Factoids

(C) 2008 California State Parks(C) 2008 California State Parks 11

NorthernNorthernElephant Elephant

SealsSealsFactoidsFactoids


TaxonomyTaxonomy

Class: MammaliaClass: Mammalia Order: PinnipediaOrder: Pinnipedia Family: PhocidaeFamily: Phocidae Genus / Species: Mirounga Genus / Species: Mirounga

angustirostrisangustirostris


DivingDiving

Can dive to more than 5000 feet (average 1000 – Can dive to more than 5000 feet (average 1000 – 2000)2000) 2nd deepest diving animal in the ocean2nd deepest diving animal in the ocean Sperm whale can dive more than 1-1/2 milesSperm whale can dive more than 1-1/2 miles

Average dive: 20 minutesAverage dive: 20 minutes Longest known dive: 2 hoursLongest known dive: 2 hours Less than 5 minutes on surface between divesLess than 5 minutes on surface between dives

Swim 10 – 15 mphSwim 10 – 15 mph


Breeding, Birth & GrowthBreeding, Birth & Growth

First males arrive DecemberFirst males arrive December First females late DecemberFirst females late December

Gives birth 3 – 6 days laterGives birth 3 – 6 days later Gestation 7 months but…Gestation 7 months but…

Delayed implantation Delayed implantation 5 months 5 months



Females reach sexual maturity at 2 Females reach sexual maturity at 2 years oldyears old

Begin giving birth at 4 years oldBegin giving birth at 4 years old Males reach sexual maturity at 6 or 7Males reach sexual maturity at 6 or 7 Males normally mate at 9 or 10Males normally mate at 9 or 10



Breeding seasonBreeding season December through mid-MarchDecember through mid-March

Average harem: 20 femalesAverage harem: 20 females



Females come into heat 19 days Females come into heat 19 days after giving birthafter giving birth

Receptive only 4 daysReceptive only 4 days



2/3 of males don’t breed2/3 of males don’t breed Milk is 54.5% fatMilk is 54.5% fat

Richer than any other mammalRicher than any other mammal Adults may lose 50% of body weight Adults may lose 50% of body weight

during breeding seasonduring breeding season


MoltMolt

MoltingMolting Females: April / MayFemales: April / May Young males: May / JuneYoung males: May / June Adult males: July / AugustAdult males: July / August

Stay in muddy water, beachStay in muddy water, beach ““Catastrophic” moltCatastrophic” molt


Annual Cycle - MaleAnnual Cycle - Male

Life span: 14 yearsLife span: 14 years Maturity: 9 years oldMaturity: 9 years old

8 months at sea8 months at sea 4 months post breeding4 months post breeding 4 months post molt4 months post molt

On landOn land 3+ months for breeding3+ months for breeding 3-4 weeks for molt3-4 weeks for molt


Annual Cycle - FemaleAnnual Cycle - Female

Life span: 20 yearsLife span: 20 years Maturity: 2-4 years oldMaturity: 2-4 years old

10 months at sea10 months at sea 2 months post breeding2 months post breeding 8 months post molt8 months post molt

On landOn land 5 weeks for breeding5 weeks for breeding 3-4 weeks for molt3-4 weeks for molt


Annual Cycle - JuvenileAnnual Cycle - Juvenile

10 months at sea10 months at sea 5 months post breeding5 months post breeding 5 months post-fall haul-out5 months post-fall haul-out

On landOn land 1 month for breeding1 month for breeding 1 month for post-fall haul-out1 month for post-fall haul-out


Annual Cycle - WeanersAnnual Cycle - Weaners

5 months at sea5 months at sea Leave beach 3-1/2 months oldLeave beach 3-1/2 months old Return for fall haul-outReturn for fall haul-out


Time LineTime Line

NovemberNovember Sub-adult males haul-outSub-adult males haul-out Mature males begin to arriveMature males begin to arrive

DecemberDecember Mature males arriveMature males arrive Females arriveFemales arrive First births mid-monthFirst births mid-month


Time LineTime Line

JanuaryJanuary Females continue arrivingFemales continue arriving Peak of births last 2 weeksPeak of births last 2 weeks

FebruaryFebruary Births continueBirths continue Peak mating mid-monthPeak mating mid-month Females leaveFemales leave


Time LineTime Line

MarchMarch Last adults leaveLast adults leave Weaners learn to swimWeaners learn to swim

AprilApril Females return to moltFemales return to molt Juveniles return to moltJuveniles return to molt


Time LineTime Line

MayMay Females moltFemales molt Juveniles moltJuveniles molt

JuneJune Sub-adult males return to moltSub-adult males return to molt


Time LineTime Line

JulyJuly Sub-adult males moltSub-adult males molt Adult males moltAdult males molt

AugustAugust End of male moltEnd of male molt


Time LineTime Line

SeptemberSeptember > 1 year olds haul-out> 1 year olds haul-out Juveniles haul-outJuveniles haul-out

OctoberOctober > 1 year olds haul-out> 1 year olds haul-out Juveniles haul-outJuveniles haul-out


Population IssuesPopulation Issues

180,000 elephant seals 180,000 elephant seals Population between 8 and 20 100 Population between 8 and 20 100

years agoyears ago Hunted for their oil for lampsHunted for their oil for lamps

Majority of hunting over 15 year periodMajority of hunting over 15 year period Just like sperm whalesJust like sperm whales


Population IssuesPopulation Issues

The few remaining elephant seals The few remaining elephant seals started a new population and there started a new population and there are now 2 main colonies with other are now 2 main colonies with other little ones here in Northern Californialittle ones here in Northern California


ColonizationColonization

First on Ano Nuevo in 1955First on Ano Nuevo in 1955 First pup 1961First pup 1961

First at Piedras Blancas 25 November First at Piedras Blancas 25 November 19901990 First pup 1992First pup 1992


Colonies


Males

Females

Migration


MiscellaneousMiscellaneous

Meaning of “Año Nuevo”Meaning of “Año Nuevo” First seen by Spanish explorers on 3rd of First seen by Spanish explorers on 3rd of

January 1603January 1603 Northern elephant seal is larger than Northern elephant seal is larger than

SouthernSouthern

Northern Elephant Seals Factoids

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