Northern Fur Seal
Life Span
Life span and survival rates of males
and females have been estimated from the age composition
of seals collected for scientific research by the United
States and Canada (1968 – 1974). The ages of seals
collected was determined by counting the annual growth
rings on the upper canine teeth. |  |
|
| MALES |
Males reach sexually maturity at 4 – 5 years old, but usually
don’t breed until 10 years old. |
Competition between males for breeding territories
is intense, and only the largest males are successful in obtaining
and defending territories. |
| Age and body
measurement data show that male fur seals reach their maximum
mass at age 8 – 11 years. |
The annual mortality rate of territorial
males (≥ 10 years old) is approximately 38% (mostly due
to fighting and fasting during the breeding season), and the maximum
life expectancy of a breeding male is 17 years old.
|
| FEMALES |
Females are capable of producing a single pup yearly from age
5 – 7 to age 23 years. |
After birth, females tend to have
a lower mortality rate than males (many males die between birth
and age 8 – 10 years).
|
The
maximum life expectancy for a breeding female is 26 years old. |
