Seals are carnivorous aquatic mammals with front and hind feet modified as flippers, or fin-feet. The name seal is applied broadly to any of the fin-footed mammals, or pinnipeds. The two species of seal predominantly found along the Cape and island’s shoreline are the harbor and grey seal. These are sometimes joined in these waters by two or three other species of seals—harp, hooded, and, most rarely, ringed seals.
It is believed that some 30 million years ago, seals evolved from bears. As the climate gradually changed and the water cooled, the bears abandoned the land for the sea. Though their true ancestry ties them to bears, harbor seals are most commonly compared to dogs. In fact the Latin name for the harbor seal—Phoca vitulina concolor—translates loosely in English to “sea dog.” Grey seals have also been compared to horses too, and they’re often called horse-head seals because the head is horse like and massive compared to the head of the harbor seal. A male grey seal can reach 8 feet in length and weight up to 800 pounds, while the female is smaller reaching only 7 feet in length and weighing 550 pounds.
Cape Cod is a great spot to see seals. It is estimated that as many as 3,000 to 5,000 seals inhabit the waters of Cape Cod year-round, and because these waters surround our peninsula, there are lots of places where you can see them without ever leaving land. The best time to spot them is November through April. Popular viewing spots are at Chatham, Wellfleet, Provincetown, and Woods Hole.
The majority of the seals found here are harbor seals and grey seals, and, though they spend most of their time along South Monomoy Island in Chatham, out of sight of land, they have been moving in recent years to sites further north, such as North Beach, Tern Island, and Aunt Lydia’s Cove, across from the Chatham Fish Pier, as well as Nantucket Sound and Vineyard Sound.
The best time to view seals is at low tide. When the tide goes out and the sandbars are left exposed, seals generally haul themselves out on land to rest, conserving energy and gaining body heat from the sun. Generally, between September and October, the large population of grey seals begins to arrive in the waters of Cape Cod. The breeding season, especially for grey seals, runs from late September through early March. During this time, the pups are born on the barrier beaches or the Monomoy Island shores.
Of course you can also meet them in the water too. A seal cruise is a great way to view these elusive marine mammals. A trained naturalist will be on board and will instruct you to keep your eyes open as the boat approaches a seal population. At first they will appear way off in the distance as black dots bobbing in the surf, or like dark rocks protruding from the water. But as the boat draws closer, you’ll see that these dark spots are seals, and that they are everywhere—and what a thrilling sight it is. There’s nothing quite like hearing the bark and chatter of seals as they frolic in the water, and you’ll certainly have a better appreciation for these sleek mammals after seeing their big brown eyes inquisitively looking your way.
If a seal cruise interests you, there are a number of seal cruise tours that leave from
Stage Harbor in Chatham, during the summer months,
and out of Ryder’s Cove in North Chatham from October through May.
You can inquire at: