Common dolphins turn up off Massachusetts mostly in the colder months, and Cape Cod National Seashore alone accounts for the majority of the state’s named sightings, its outer beaches giving a clear vantage on the deeper water this species prefers over the shallow bays closer to shore.
Records peak sharply in January, ease through spring, and nearly vanish by June, the reverse pattern of the state’s summer-heavy humpback and fin whale records. That winter bias likely reflects common dolphins following cold-season prey schools closer to the Massachusetts coast, then moving offshore or north as waters warm through the summer.
Full species profile
