Northern Elephant Seal
Elephants Seals belong to the Mammalian Order Pinnipedia, in the
family Phocidae. Other members of Phocidae include harbor seals,
gray seals, and monk seals. Phocids are referred to as true seals.
They are distinguished from other pinnipeds by their inability to
support their body using their hind limbs. The Northern Elephant
Seal's genus name, Mirounga, is derived from the Australian
Aboriginal word for seal, miouroung. Its specific name,
augustirostis, means "narrow rostrum". This is referring to
the Northern Elephant Seal's long snout, which is narrower than the
Southern Elephant Seal's snout.
Seals are known for their sexual dimorphism, males can be almost
five times larger than females in this species. Northern Elephant
Seal males can weigh over 5,000lbs. However, females of this
species only grow as large as 1,400lbs. Another feature of these
seals that relates to male-female differences also explains how this
species got its name. The male seal's proboscis is an enlarged
Northern Elephant Seal can be found along the Pacific coast of North
America from Baja California up to the Aleutian Islands of Alaska.
Squid, rays, skates, small sharks, and Pacific hake compose the
elephant seal's diet. Elephant seals can hold their breath for up
to 80 minutes and dive to depths of 5,000ft to search for prey. The
average length of time an elephant seal will hold its breath for is
seals were named "elephant" because their "noses" resemble the
trunks of elephants. Despite this superficial similarity, the
seals' proboscis has a different purpose entirely. The male
elephant seal uses his " trunk" as a resonance chamber to help make
its roars sound as loud as possible. This is particularly important
during the breeding season when elephant seals haul out on beaches
Northern Elephant Seal's breeding season begins in early December.
This is when the males begin to establish their territories while
waiting for females to arrive. By the middle of December pregnant
females start to arrive on shore to find a spot on the same beaches
to give birth. They give birth around the third week in December
and immediately start to nurse their young. This time period known
as the pupping season continues until the first week in February.
It is only after the females have given birth, that they begin to
mate with the males on the beach.
breeding male and female elephant seals remain on the rookery and do
not feed during this whole time period. They therefore must spend
these 3-4 months subsisting on the fat stores on their body. One
can thus easily understand why it is advantageous for both male and
female elephant seals to go into their breeding season with ample
stores of fat. Large size gives males a greater advantage while
establishing dominance on a beach, and it allows them to hold onto
their territories 24hrs per day while living off their fat
provides an advantage to females by giving them the nutritive energy
to invest into their pups. Elephant seal milk is very oily and high
in fat content. A well nursed pup grows from 20 pounds at birth to
150 pounds in only three weeks! In the elephant seal world, a fat
baby is a healthy baby, and that depends entirely on its mother's
ability to tap her own fat reserves in producing milk.
elephant seal's size is so important that some elephant seal pups
will nurse not only from their
own mother but will steal milk from other females as well. This
will not only help them survive immediately when they return to sea,
but it will also make them grow to a larger size which will aid them
in the future when they return to the rookery to mate.
very important time period in an elephant seal's life is its molting
period, which takes place once a year. This is the time where
elephant seals shed their old coat of fur and grow in a new one.
Elephant Seals must come to land while molting. This is for three
reasons. First is because they are very susceptible to the cold
while losing their old fur. Secondly, their old coat needs to be
warm and dry in order to flake off. Third, they use the sand and
the rocks on the beach to rub up against to help get their old coat
Seals were easily hunted for their meat because of the return to
their customary beaches each year for breeding and molting. They
are slow moving on land. This led to massive slaughtering of
elephant seals species in both the Northern and Southern
Hemispheres. Due to the careful protection of their rookeries, the
elephant seal population on the west coast of North America is
starting to make a comeback. But we must remain vigilant and extend
this same level of protection to other areas throughout the Pacific
Ocean so that this species will once again thrive.