Learn more about the fascinating lives of marine mammals and sea turtles with our collection of informational fact sheets, activities and coloring pages!
Harbor seals are the most common seal in our waters, migrating into New Jersey and as far south as North Carolina each winter. Most stranded harbor seals in our area are yearlings or second-year animals. Adult harbor seals can grow up to 5 feet long and weight 200lbs. They are brown in color with mottled spots, and heart-shaped nostrils.
As their name implies, harbor seals often seek out the protection of quiet bays and inlets. Individuals may utilize floating docks and jetties to rest. They may also be found in large colonies of up to 200 seals, taking advantage of prime haul out locations such as sandy shoals and partially submerged rocks that are free from human contact.
Grey seals are the second most common seal found in New Jersey waters, migrating south to our area every winter. Like the harbor seals, most stranded grey seals in New Jersey are less than two years old.
Grey seals are sexually dimorphic, males are larger and primarily black in color, and the females are mostly grey with dark spots. As adults they weigh 400-800lbs. Grey seals have a large Roman nose, earning them the nickname of "horsehead seals".
Harp seals are artic seals, giving birth (whelping) on the pack ice from the Gulf of St. Lawrence and further north. In recent years, their numbers have been increasing in New Jersey during the winter. An iconic arctic species, harp seals are born with a coat that is completely snow white (lanugo). Harp seals shed their lanugo after one month, molting into a spotted coat.
At 2-5 years of age, a harp seal's markings will change again, developing a black head and the black harp-shaped pattern from which they get their name. In New Jersey we typically see young harp seals, however adults are becoming more prevalent, and we have also admitted one harp seal pup still in lanugo.
Hooded seals are arctic seals, sharing range and whelping grounds with harp seals. They are rare visitors to New Jersey, the last hooded seal stranded here in 2008. Hooded seals can be nomadic, and some have wandered far out of range, as far south as Florida. Hooded seal pups are called "bluebacks" because of their bluish-grey coat. Adult males have a dark "hood" on their forehead and a red nasal sack that they inflate to startle rivals and predators
Hooded seal pups are born in the spring and weigh about 50lbs. Due to the harsh climate they are born in, hooded seal pups only nurse from their mothers for approximately four days before they are weaned. In that short time, pups will gain up to 15lbs per day, more than doubling their birth weight. Hooded seal milk has the highest fat content of any mammal (61%).
Ringed seals are the smallest and most abundant of the arctic seal species, getting their name from light ring markings on their back. They are circumpolar, rarely straying beyond ice-covered waters. Ringed seals are the primary prey of polar bears. Mothers will give birth and nurse their pups in snow-covered lairs for protection.
Ringed seals are rare in New Jersey, with only two ever having stranded here. Both ringed seals stranded a few weeks apart in 1990. One came ashore deceased, and the other was successfully rehabilitated and flown up to Cape Cod for her return to the wild.