Harbor Seal

More Information

Harbor seals are medium-sized pinnipeds, with front and rear flippers. Adult males can get up to 6 feet long and weigh 300 pounds. They vary in color from white to brownish-black. They have cold-water adaptations such as blubber, a high metabolic rate that lets them generate heat, and the ability to push blood to their extremities to conserve heat at their core.

They are solitary at sea but can be gregarious on land and tend to get together when food availability is high in an area. They generally group themselves with other harbor seals of the same sex or age. They molt once a year. Breeding takes place between March and August, and males mate with several females each season. Pups are born at different times depending on region. These marine mammals reach maturity between 3 and 7 years of age.

Did You Know?

• Harbor seals have the widest distribution of any seal in the world.
• Harbor seals can dive for up to 30 minutes at a time and can reach depths of 1,460 feet.
• They are well adapted to diving; they can rely on oxygen stored in their blood and muscle tissues when underwater and can move blood away from extremities to their core to maintain brain, heart, and lung function. They also slow their heart rate.