A lucky few were treated to the sight of whales emerging from the waters of South Beach Sunday.

A few minutes' walk from the end of Katama Road, Nalin Storm, 22, saw the whales slapping the surface of the water with their fins and tails just before noon.

Mr. Storm captured the marine mammals off South Beach and shared the video with the Gazette.

“It was pretty awesome to see,” he said. “It was my first time seeing whales.”

He said the beach wasn’t crowded, and that people who were there began taking videos once they noticed the whales slowly moving along the shore towards Chappaquiddick.

Charles “Stormy” Mayo, who directs the right whale ecology program at the Center for Coastal Studies in Provincetown, said the whales were likely humpback whales, which come fairly close to the shore on occasion.

“It’s not a rare event,” he said. “It's a little close to the land, but these animals are capable of swimming right up against the shore so long as they've got enough depth of water under them.”

Mr. Mayo explained that he is aware of some air surveys that have shown a “fair number” of humpback whales off the Vineyard and Nantucket.

Slapping the surface and being close to shore isn't unusual for whales, he said, though the impetus can't be clear.

“You can imagine that's in the mind of the whale — and not for us to decipher,” Mr. Mayo said.