The waters surrounding Cape Cod serve as a habitat for various marine mammals, including several species of seals. These creatures have been part of the region’s ecosystem for thousands of years, with archaeological evidence indicating their presence. The marine environment here provides a suitable home for these animals, making Cape Cod a notable location for seal observations.
Common Seal Species
The most common seal species in Cape Cod are the Gray Seal (Halichoerus grypus) and the Harbor Seal (Phoca vitulina). Gray seals are larger, with adult males reaching up to 8 feet long and weighing over 800 pounds, while females are smaller. Their distinctive head shape, often horse-like, features wide-set nostrils that form a “W” shape. Gray seals exhibit varied coloration ranging from black, tan, silver, to white, with males typically darker with light patches and females lighter with dark spots.
Harbor seals are smaller, around 5 feet long, with a weight up to 285 pounds. Their coat color can vary from reddish-tan to silver or nearly black, often displaying a blue-gray back with light and dark speckling. A distinguishing feature of harbor seals is their close-set, V-shaped nostrils and a more dog-like facial structure. Less common species like Harp seals and Hooded seals can occasionally be sighted in Cape Cod, particularly during winter months.
Seal Presence and Behavior
Seals are drawn to Cape Cod’s waters due to plentiful food sources and suitable resting locations. Their diet includes a variety of fish such as cod, mackerel, and herring, alongside crustaceans, squid, and octopus. This foraging ground supports a healthy seal population. Seals utilize sandy beaches, sandbars, and rocky outcrops as “haul-out” sites for resting, molting, or giving birth.
Seals commonly “haul out,” resting on land, sometimes for extended periods. Gray seals, in particular, establish seasonal haul-out areas where they rest daily, often correlating with low tide exposures of large sandbars. Their movements and foraging patterns can also be influenced by predators; for instance, gray seals have been observed to shift to nocturnal foraging and limit offshore activity during months with higher white shark presence. This adaptation helps them manage predation risks.
Coexisting with Seals
Observing seals in their natural habitat requires adherence to guidelines that ensure both human safety and the animals’ well-being. Maintain a respectful distance from seals, generally at least 50 yards, whether in the water or on shore. This distance helps prevent disturbance to their natural behaviors. The Marine Mammal Protection Act prohibits harassing, feeding, or otherwise disturbing marine mammals, including seals.
Approaching or attempting to interact with seals can cause stress to the animals and may be illegal. If a seal appears stranded, injured, or in distress, contact a local wildlife rescue organization, such as the International Fund for Animal Welfare (IFAW) hotline for Cape Cod. Do not attempt to help the animal yourself, as trained professionals are best equipped to assess the situation and provide necessary assistance. Keeping dogs leashed near seal habitats also helps prevent disturbances.