Elephant SealsElephant SealsBy:By:

Jen CooleyJen Cooley

Megan FloxMegan Flox

Northern

OverviewOverview

Species TraitsSpecies Traits Breeding BehaviorsBreeding Behaviors Sexual DimorphismSexual Dimorphism Underwater ExpertiseUnderwater Expertise ForagingForaging HabitatHabitat EcosystemEcosystem Human ImpactHuman Impact Q & AQ & A SourcesSources

Species TraitsSpecies Traits

The northern elephant seal The northern elephant seal is a large marine mammal.is a large marine mammal.

Adult males weigh 2-7 times Adult males weigh 2-7 times more than adult females.more than adult females.

Adult males measure up to Adult males measure up to 4.5 m long and weigh up to 4.5 m long and weigh up to 2300 kg.2300 kg.

Adult females measure up Adult females measure up to 3.6 m long and with up to to 3.6 m long and with up to 750 kg.750 kg.

Males live up to 17 years Males live up to 17 years and females to 22 years.and females to 22 years.

Species TraitsSpecies Traits

Coat is dark gray to Coat is dark gray to brown.brown.They have an annual They have an annual molt on the shore molt on the shore during the warmer during the warmer months between months between March and July for March and July for about 2-3 weeks. about 2-3 weeks. It's called a “radical It's called a “radical molt” because the fur molt” because the fur comes off in sheets.comes off in sheets.

Species TraitsSpecies Traits

Each sex and age class Each sex and age class molts at a different time, molts at a different time, beginning with immature beginning with immature seals early in the season seals early in the season and ending with bulls and ending with bulls which molt in July.which molt in July.In the Autumn juvenile In the Autumn juvenile seals congregate at the seals congregate at the colony sites for around 2 colony sites for around 2 months beginning in late months beginning in late September and lasting September and lasting until November.until November.

Breeding BehaviorsBreeding Behaviors

Polygamous (one male Polygamous (one male with multiple females).with multiple females).Females reach sexual Females reach sexual maturity 3-5 years old maturity 3-5 years old and males 4-6 years.and males 4-6 years.Males reach their Males reach their productive peak at 9-12 productive peak at 9-12 years.years.Large adult males arrive Large adult males arrive at the breeding grounds at the breeding grounds in December to compete in December to compete for access to females.for access to females.

Breeding BehaviorsBreeding Behaviors

Females usually give Females usually give birth to the previous birth to the previous year’s pup in January.year’s pup in January.Pups are born 1.5 m long Pups are born 1.5 m long and 30 kg in weight.and 30 kg in weight.Pups are born with black Pups are born with black hair which is replaced by hair which is replaced by a silvery coat after they a silvery coat after they are weaned about 3-4 are weaned about 3-4 weeks later.weeks later.

Sexual DimorphismSexual Dimorphism

Male Elephant Seal Female Elephant Seal

When males reach puberty at about 7 years old, they develop a large inflatable nose, or "proboscis." Adult males inflate it during the winter

breeding season to resonate sound when vocally threatening each other.

Underwater ExpertiseUnderwater ExpertiseElephant Seals are able to dive Elephant Seals are able to dive very deeply and for extremely long very deeply and for extremely long periods of time.periods of time.Males can dive 350 to 800 meters. Males can dive 350 to 800 meters. Females can dive 300 to 600 Females can dive 300 to 600 meters.meters.Dives are average 13-17 minutes Dives are average 13-17 minutes longer for males followed by a brief longer for males followed by a brief 3 minute surface interval.3 minute surface interval.They remain submerged 80-95% of They remain submerged 80-95% of the time spent at sea.the time spent at sea.Researchers have identified 5 Researchers have identified 5 different dive patterns, they different dive patterns, they associate with travel, sleep and associate with travel, sleep and foraging.foraging.They also have a habit of holding They also have a habit of holding their breath for as long as 25 their breath for as long as 25 minutes.minutes.

Underwater ExpertiseUnderwater Expertise

ForagingForagingElephant Seals are the only Elephant Seals are the only mammals with a biannual mammals with a biannual migratory pattern.migratory pattern.Carnivorous (Kingdom Animalia, Carnivorous (Kingdom Animalia, Phylum Chordata, Class Phylum Chordata, Class Mammalia, Order Carnivora, Mammalia, Order Carnivora, Family Phocidae, Genus Family Phocidae, Genus Mirounga).Mirounga).Females will travel from California Females will travel from California and Baja all the way to Mexico to and Baja all the way to Mexico to feed.feed.Males will travel from California Males will travel from California and Baja to the Gulf of Alaska to and Baja to the Gulf of Alaska to feed.feed.Cephalopods are an important Cephalopods are an important part of the elephant seal’s diet as part of the elephant seal’s diet as well as rays, Pacific Whiting, well as rays, Pacific Whiting, sharks, skates and pelagic red sharks, skates and pelagic red crabs.crabs.

HabitatHabitatCalifornia has about California has about 84,000 northern elephant 84,000 northern elephant seals. seals. Mexico has about 32,000 Mexico has about 32,000 northern elephant seals. northern elephant seals. Northern elephant seals Northern elephant seals spend much of the year, spend much of the year, generally about 9 months, generally about 9 months, in the ocean.in the ocean. They congregate onshore They congregate onshore during breeding season, during breeding season, molt season, and the molt season, and the juvenile “haulout” period in juvenile “haulout” period in the autumn.the autumn.

Dark Blue: Breeding Colonies Light Blue: Non-Breeding

Individuals

EcosystemEcosystem

Predators of Northern Elephant Seals

Great White Sharks Orcas

Prey of Northern Elephant Seals

Fishes and Skates Rays and Sharks Pelagic Red Crabs Cephalopods

Human ImpactHuman ImpactElephant seals were nearly hunted to extinction Elephant seals were nearly hunted to extinction for their blubber in the 19th century.for their blubber in the 19th century.Received protection under U.S. and Mexican law Received protection under U.S. and Mexican law and the species recovered.and the species recovered.Genetic diversity is low because recovered Genetic diversity is low because recovered population came from only a few ancestors.population came from only a few ancestors.Entanglement in gillnets still causes around 100 Entanglement in gillnets still causes around 100 deaths per year.deaths per year.Entanglement in marine debris, fishery Entanglement in marine debris, fishery interactions, and boat collisions are their main interactions, and boat collisions are their main threats.threats.

Q & A SourcesQ & A Sources

www.elephantseals.orgwww.elephantseals.org

www.marinebio.orgwww.marinebio.org

www.nmfs.noaa.govwww.nmfs.noaa.gov