How to Identify Seal in New Hampshire

Harbor Seals are the smallest, reaching 5 to 6 feet long. Grey Seals are noticeably larger, typically 6 to 7 feet or more, giving them a heavier, bulkier appearance in the water. Harp Seals are medium-sized at around 5 to 6 feet, but their slender build and long body make them appear different from stocky Harbor Seals. When seals haul out on rocks or ice, size is one of the first clues. If you see a small, compact seal, it is likely a Harbor Seal. A much larger, robust animal is almost certainly a Grey Seal.

Harbor Seals have a small, rounded head and a large, dark eye set forward on the skull. Their body is plump and compact. Coloring ranges from light tan or silver to dark brown or gray, often with irregular spots or blotches. The nostrils are V-shaped and close together, giving the face a cat-like look. In the water, they often hold their heads high and bob vertically, an unmistakable behavior called 'bottling.' On land, Harbor Seals remain alert and usually slip into water if approached. They are the species most likely to be seen in New Hampshire.

Grey Seals have a long, narrow head that is flatter than a Harbor Seal's, with a more prominent brow. The nostrils are D-shaped or parallel rather than V-shaped. Large adults have a hefty, sausage-like body shape. Color is typically grey, brown, or tan, often with dark patches or a lighter belly. The eyes are set further back on the head than in Harbor Seals. Grey Seals tend to haul out in groups and are less shy than Harbor Seals. They are becoming more common in New Hampshire but still represent a smaller fraction of sightings than Harbor Seals.

Harp Seals are slender and streamlined compared to the stockier Harbor and Grey Seals. Adults often show distinctive black and white or dark gray coloring. Young Harp Seals ('whitecoats') have creamy white fur, and juveniles may show spotting or mottling. The head is small and pointed. Harp Seals are highly migratory and breed in Arctic ice, so sightings in New Hampshire are rare and usually occur in winter or early spring when individuals disperse southward or get caught in ice. Most Harp Seal records in the state come from stranding reports or rescue efforts.

Harbor Seals show the most variability in color, ranging from pale silver to almost black, and most have irregular spots or streaks. Grey Seals are typically darker and often appear more uniform in color, though they may show a lighter belly. Harp Seals, when present, are usually recognizable by their contrasting white and dark colors or by the pale, uniform coat of younger animals. Color alone can be misleading because of lighting and water conditions, so combine it with size, head shape, and behavior.

Winter and early spring offer the most opportunity to see seals. January, February, and May are peak months when numbers are highest. Look along rocky shores, jetties, and breakwaters on calm days. Binoculars are essential because seals will dive or swim away if approached too closely. Boat tours in coastal areas sometimes encounter seals in their natural habitat. Remember that all seals are wild animals and it is illegal to approach within a certain distance; regulations in New Hampshire generally require staying at least 150 feet away.

Grey Seals have expanded their range northward along the Atlantic coast over the past two decades. They were nearly hunted to extinction but their populations have recovered significantly since protection laws took hold. As their numbers grow in southern New England, more Grey Seals move into New Hampshire waters, especially in winter. This expansion has also increased sightings of Harp Seals and other Arctic species that follow prey into southern regions during cold months.

If you encounter a seal that appears injured, entangled, malnourished, or stranded on shore and unable to return to water, contact the Marine Mammal Stranding Network or a local wildlife rehabilitation center immediately. Do not attempt to touch, feed, or remove the animal yourself. Photos from a distance can help rescuers. Seals sometimes rest on shore and will leave on their own, so observe from afar and note its condition. Any seal that shows signs of distress or remains out of water for an unusually long time warrants a call to authorities.

Harbour Seals produce barks, growls, and underwater clicks, especially during breeding season. Grey Seals make deeper growls and bellows. Harp Seals have high-pitched calls and clicks used underwater for communication. On land, seals are generally quieter than sea lions, and vocalizations are rarely the primary identification tool. However, distinctive barks from a hauled-out seal might hint at which species you are watching. Most identification relies on visual field marks rather than sound.

The National Oceanic and Atmospheric Administration (NOAA) maintains identification guides and photos of northeastern seal species. The Marine Mammal Center and the New England Aquarium publish identification charts and research on seal behavior and distribution. Local naturalist guides and whale-watching tour operators often provide field-proven tips for identifying seals in your region. Books on New England marine mammals also cover seal identification and ecology in detail.