Elephant Seal Stats, Age Brackets, Charts, Mortality Rates & Illnesses

Elephant Seal Stats

Pups: 3-4 feet at birth 60-80lbs at birth

Weaners: 4.5+ feet 170-330 lbs

Adult Female: 8-9 feet 800-1,500+lbs

Female:

reaches sexual maturity at 3-4 years

first birth usually at 4 years

gestation lasts about 11 months, including the 3-month

delayed implantation

reaches physical maturity at about 6 years

lives up to 20 years

Adult Male: 15+ feet 3,000-5,000+lbs

Male:

reaches sexual maturity at 5-6 years proboscis starts to grow around 4 years

reaches physical maturity at about 9 years

lives up to 14 years

Age Brackets

Pups: 1 day to 4 weeks

Weaners: 4+ weeks to 1 year

Juvenile Female: 1 to 2 years

Adult Female: 3 to 20 years

Juvenile Male: 1 to 4 years

Sub-Adult Male: 4 to 7 years

Adult Male: 7 to 14 years

Charts

Mortality Rates

Pup mortality rates vary from year to year and location to location. On average. about 25% of pups die during their first month.

Weaner mortality rate is higher and averages about 50%.

As elephant seals get older and bigger, their mortality rate drops.

Adult male mortality rate is presumed higher than an adult female's.

Despite these fairly high mortality numbers, the current elephant seal population is estimated to be growing at about 10% per year.

Illnesses

Elephant seals can and do contract varying illnesses, and scientists worry that a dangerous pathogen could wipe out the entire population. The reasoning behind this is the belief that there may not be enough genetic diversity in the current northern elephant seal population, descended from the one hundred or so animals that managed to evade the hunters in the early 1900s.

One and two-year-old elephant seals often suffer from a skin disease known as the northern elephant seal skin disease or NESSD for short. This form of dermatitis is also often referred to as scabby molt. This ulcerative skin disease can either infect a small portion of the fur and underlying skin or spread to cover up to 60% or more of this outer protective layer. Although, in most cases, the elephant seals heal up without any further problems, sometimes, secondary bacterial infections and/or sepsis can lead to death.

Another disease of the skin is sealpox, which is caused by a virus. The small lumps caused by this disease occur mainly on the head and neck. These approximately one inch lumps in the skin will break open, ooze, and then heal leaving a grayish raised scar without fur.

Another fairly common illness that elephant seals can develop is bacterial pneumonia.

Besides being vulnerable to bacterial and viral illnesses, elephant seals can also become sick from fungal or parasitic infections.

So far the toxic effects from domoic acid poisoning have not appeared to affect elephant seals. This toxin usually affects the brain causing rapid neurological deterioration and eventual death. ( See Wikipedia: domoic acid. )

Sometimes you can see one or more abscesses on the backs of juvenile or sub-adult males. These fist-size swellings are the result of infected bites that were dealt out during their many fights. These swellings will eventually burst open, drain and then heal.

Injuries

The type of injuries male elephant seals mostly tend to get are those inflicted by other elephant seals such as cuts, scratches, or ripped open skin. Mostly it's the sub-adult and adult males that collect quite visble ' battle scars ' during their often intense fights for dominance, turf, or mating rights.

Other injuries to both male and female elephant seals can come from encounters with orcas, great white sharks or other types of sharks including the cookie cutter shark.

Then there's the occasional run-in with man, where the federally protected elephant seals sometimes get hurt by fishing gear or boats.

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