Beyond the Aquarium
Do Not Disturb!
It is completely normal for seals to haul themselves out on the shore. Please leave them alone!
Seals that are seen on the shore in New England—even young seals on their own—are not necessarily stranded or in need of help. Seals are semi-aquatic, meaning they spend some of their lives in the water and some of it on land. They haul out on rocks or the shore to warm and dry in the sun, molt, give birth, or sometimes just to rest. Seals don’t need to stay wet and can go days without eating. Seal moms provide very high fat milk to the nursing pups, which allows the pups to wean and head out on their own very early in life.
We know the desire to help an animal can be overwhelming, especially if it’s a pup by itself, but do not disturb the seals. The vast majority of the time what they need most is valuable rest and to be left alone by humans. Our visible presence is ALWAYS stressful to a young seal that is struggling to survive.
All marine mammals, including the seals you’ll see around Boston, are protected by federal law under the Federal Marine Mammal Protection Act. The law makes it illegal to disturb, feed, hunt, or otherwise harass any marine mammal. Keep a distance of 150 feet, leash dogs, be quiet, and ask others to do so as well. Take the opportunity to observe these remarkable animals from a safe distance!
Most seals on the beach are perfectly healthy, but sometimes they do need human assistance. Know the signs so you don’t do more harm than good!
Does the seal have any obvious injuries, gunky eyes, or look skinny or underweight? If you’re concerned with the health of a seal, do not approach it. Watch it closely from a distance. Note its location, size, coloring, and odd behavior or obvious injuries. Take pictures without approaching. If the animal appears in distress, it is entangled in fishing gear or rope, or is being harassed, call the marine animal rescue team in your area or the animal control officer of the town. If the animal was seen on beaches from Plymouth to Salem, call the New England Aquarium’s stranding hotline at 617-973-5427.
Meet New England’s Neighborhood Seals!
There are two species of seals that spend all their time in Massachusetts’ waters, and a few others that stop by during migration.
Harbor Seals (Phoca vitulina)
Neighborhood Status: Always around!
Harbor seals are one of the most common marine mammals along both the East and West coasts of the United States. Like the harbor seals that live at the New England Aquarium, harbor seals in the wild have short faces and coats of tan, silver, or blue-gray with dark speckling or spots. Pups are born May through June in northern New England, and they nurse for four to six weeks. During this time, mother seals may sometimes leave the pup to forage for food. Harbor seal pups are able to swim just moments after birth! Like the adults, seal pups haul out on the shore to rest and regulate their body temperature.
When grown, harbor seals weigh 180 to 285 pounds and can be up to 6 feet long. Males are slightly larger than the females. They live to about 25 to 30 years old.
Gray Seals (Halichoerus grypus)
Neighborhood Status: Always around!
Sometimes called “horseheads” because of their longer snouts. Gray seal pups are born between December and February with fluffy gray-white fur that helps absorb sunlight and trap heat to keep the pups warm. They stop nursing at about 18 days old, which is also when they shed their fluff. After that the pups on their own. An important note from NOAA: “Gray seal pups are very vocal, and can sound like a baby crying, but this is normal behavior and doesn’t necessarily mean that the pup is in distress. This vocalization helps the mother find the pup when she returns from foraging.”
When grown, male gray seals can be up to twice as large as the females! Female gray seals are about 7.5 feet long and weigh about 550 pounds, while males can grow to 10 feet and weigh about 880 pounds! Males are dark with light spots, while females are light with dark spots, the males also have longer noses than the females. The male nose is so distinctive that the gray seals’ scientific name (Halichoerus grypus) means “hooked-nosed pig of the sea.” They live about 25 to 35 years.
Harp Seals (Pagophilus groenlandicus)
Neighborhood Status: Just Visiting!
Harp seals are part of a group called “ice seals.” They’re highly migratory and gather in groups of up to several thousand to molt and breed on cold northern pack ice. Annual migrations can be more than 3,100 miles roundtrip. Although considered a northern species, winter sightings of juvenile harp seals in the Southern Gulf of Maine (our backyard!) have been on the rise in the last 10 years. At birth, newborn harp seals have a fluffy white coat that they shed after they stop nursing about 12 days after they’re born. Juveniles have a light coat with widely spaced dark spots, and the adults have a silver-gray coat with a black face and a black patch on their backs that looks like (surprise) a harp!”
Grown harp seals have a robust body with a small, flat head and can grow to 300 pounds and up to 6 feet long. Their average lifespan is unknown.
Hooded Seals (Cystophora cristata)
Neighborhood Status: Just Visiting!
Hooded seals are sometimes known as “ice seals,” due to their reliance on pack ice. They live in the cold waters of the North Atlantic and Arctic Ocean, but can be seen as far south as Florida, California, and even the Caribbean! Most Massachusetts sightings are of the seals born that year. They’re named for the stretchy “hood” in their nose. To attract mates, a male can actually inflate its hood, which blown up looks like a pinkish-red balloon. Hooded seal pups nurse for only three to five days after birth—the shortest weaning time of any mammal! The pups have blue-gray fur on their backs and whitish bellies. This beautiful pelt earned them the nickname “blue-backs” and once made them a target for hunting. They shed that pelt at 14 months old.
Grown hooded seals have silver-gray fur with darker patches of different sizes and shapes across their bodies. When grown, males are about 8.5 feet long and can weigh up to 775 pounds. Females are about 6.5 feet long and weigh up to 660 pounds. Hooded seals live about 25 to 35 years.
Ringed Seals (Phoca (pusa) hispida)
Neighborhood Status: Rare sights!
Another species of “ice seal,” ringed seals are the smallest Arctic seal and a very rare sight in New England! They usually live in the arctic and subarctic regions, and prefer to stay on or near the arctic pack ice. Some years, a few wandering juveniles are seen resting on Cape Cod beaches in the winter.
Ringed seals have a short snout and a plump body. Adults grow to only 4.5 feet long or up to 150 pounds. They are named for the small, light-colored circles (rings) throughout the dark hair on their backs. They live about 25 to 30 years.
Advice on Sharing the Shore with Seals:
- Stay back (and keep pets) at least 150 feet from seals.
- Never chase seals back into the water.
- Never cover seals or try to pick up pups.
- Reduce your impact by disposing of trash properly so seals and other marine life won’t accidentally mistake it for food.