A harbor seal's age can be estimated by growth rings in their teeth. They also can stay submerged for a maximum of 40 minutes and may exceed depths of 1500'. The seals at the Brookfield Zoo often sleep on the pool bottom for 10 to 20 minute naps.
Status in the Wild
Males are slightly larger than females, but not sufficiently larger to be considered sexual dimorphism (2 distinct gender forms). Due to lack of external ear flaps and short forelimbs, harbor seals are part of the “true seal” family. Their short forelimbs limit locomotion on land. They are white-gray to dark gray-brown, with patterns of rings or spots; these patterns are light on a dark background or vice-versa. Their ventral side is generally lighter and has less spots. The pattern on the coat is unique to each seal, which can be very useful in the identification of individuals. They have torpedo-shaped bodies with round heads. They have short front flippers, used as rudders when swimming, that contain 5 digits webbed together with large claws. Their back flippers also contain 5 digits and are used mostly for forward movement while swimming.
Harbor seals are the most common seal seen along the U.S. east coast. U.S. populations are currently healthy.
Adopt a Harbor Seal
Listed as of "least concern" on the IUCN Red List (International Union for Conservation of Nature and Natural Resources)