Studies of adult northern diamondback terrapins (Malaclemys terrapin terrapin) in the salt marshes on the Atlantic Ocean side of Cape May Peninsula reveal that from mid-November through December, terrapins gradually migrate from the open waters of the sounds into the marsh creeks. Within the creeks, hibernating diamondbacks hibernate as isolated individuals or in small groups. Three hibernating methods are used: 1) resting on the bottom under water, 2) burial atop creek banks, and 3) taking refuge beneath undercut banks. Hibernating diamondbacks apparently remain dormant all winter.