You can’t mistake an adult Atlantic spotted dolphin for anything else—the spots are a dead giveaway.

This gregarious cetacean isn’t born with those beauty marks, however. Calves start out gray, like other dolphins. After about three years, they begin to develop speckles. After a few more years, mottled spots begin appearing. Finally, the dolphins mature into adults with light spots on their dark backs and darker ones on their pale bellies. But not all Atlantic spotted dolphins develop spots; those that live in the Gulf Stream far offshore often lack spots.

Atlantic spotted dolphins range across most of the warm Atlantic, usually keeping within 225 miles of the shore. They have long, narrow beaks and bulky heads and bodies.

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