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Gray Seal - Halichoerus grypus
Photo by Glen Tepke

Gray seals are the largest seals in sanctuary waters, growing to 8 feet and weighting over 900 lbs, and are distinguished by a horse-like snout, wideset nostrils and a convex forehead profile. Their fur color ranges from light gray to brown or almost black, but fur patterns are very similar to harbor seals and cannot be used to separate them. They are typically much less curious about boats and humans than are the more gregarious harbor seals.

Gray Seal
(Halichoerus grypus)

The Western North Atlantic stock ranges from New England to Labrador. Other populations are found in northwestern Europe and the Baltic. Growing population around Massachusetts, numbering over 5,000 in 1999, may be an expansion of the Canadian population, estimated at about 150,000.

Prefers cold termperate to subartic coastal areas; will haul out on isolated rocky offshore islands, breakwaters, and jetties.

Squid, mollusks, and fish, such as sand lance, herring, whiting, skates, pollock, cod, haddock and flounders.


The status of this species is representative of the populations within the waters of this Sanctuary only, not global populations.

Quick Fact
Gray seals rest at the surface in a vertical orientation, treading water with only the head and upper neck exposed.

Learn More
- NOAA Marine Fisheries
- Duke University