Some Commonly Asked Questions About Seals

Q: What is the difference between a seal and a sea lion?
A: The seals that we see on Long Island are true seals, and are members of the family Phocidae. True seals are characterized by their lack of an external ear flap. True seals also have short stubby flippers that make them very clumsy on land, and they have claws on their flippers, which sea lions do not.  Sea lions are members of the family Otariidae, whose members are characterized by the presence of external ear flaps. Sea lions also have longer necks than true seals, and are able to rotate their hind flippers underneath them, while true seals cannot.  True seals have a thick layer of blubber that keeps them warm in the cold waters they inhabit, but sea lions do not need this thick blubber layer, as they live in warmer southern waters. 

California Sea Lion                           Harbor Seal

Q: How big do harbor seals get?
A: When first born, harbor seal pups weigh approximately 8-12 kg (18-26 lbs) and are around 70-100 cm (28-40 inches) in length. Juveniles grow very quickly, and adult males can grow to be up to 1.9 meters (6 ft 3 inches) in length, and can weigh up to 170 kg (370 lbs).  Adult females are slightly smaller, reaching 1.7 meters (5 ft 7 inches) in length, and weighing in at up to 130 kg (290 lbs).

Q: What do seals eat?
A: Harbor seals feed on a variety of  schooling fish, including herring, mackerel, and flounder.  Their large teeth enable the seals to catch their prey, which they then swallow whole.

Q: How long can harbor seals stay under water?
A: Harbor seals usually dive for only a few minutes, but the longest recorded dive for a harbor seal was 31 minutes long.

Q: Why do seals haul out on the rocks?
A: Seals can be found hauled out on rocks during the low tide to rest and to absorb heat from the sun.

Q: Are harbor seals the only seals found around Long Island?
A: No. There are four species of seals that are commonly found around Long Island in the winter months: Harbor seals, Harp Seals, Gray Seals, and Hooded Seals.  Harp seals are an are the most abundant pinniped in the Northern Hemisphere, and they are found in very cold, arctic waters.  Adult harp seals can be identified by the dark, harp-shaped mark on their back, after which they are named.  Newborns are known best for their bright white coat, which is replaced by a more silverish coat after they are weaned.  Gray seals are also found in Long Island waters, and can be recognized by their horselike heads.  Male gray seals are darker in color, with light spots on their coat, while females are lighter in color, with dark spots.  Hooded seals are another arctic species which can be spotted around Long Island in the wintertime.  Adult male hooded seals are known for their extrudable nasal sac, which they inflate to attract females or to threaten other males.                                                                                   

Q: Are seals protected?
A:Yes. All seals are protected under the Marine Mammal Act of 1972, which was enacted to protect and manage marine mammals such as whales, dolphins, porpoises, seals, and sea lions.

Suggested readings :
Geraci, Joseph R. And Lounsbury, Valerie J. 1993. Marine Mammals Ashore- A Field Guide for Stranding. Texas A&M Sea Grant Publication.