UPDATED: Porpoises Washed Ashore — Not Dolphins

Two young porpoises appeared ashore on King's Beach Wednesday morning.

A field volunteer with the New England Aquarium thought the dead animals were Atlantic White-sided Dolphins.

But a biologist with the aquarium arrived on the scene later in the day, about 12:30 p.m., and determined that they were harbor porpoises.

Katie Pugliares, a senior biologist with the aquarium's stranding program, took tissue samples from one of the porpoises.

The other one had floated out to sea with the tide by the time she arrived.

Pugliares said the animal she saw was about 2 years old, and weighed about 100 pounds..

She does not know how it died.

Harbor porpoises are native to these waters and feed close to shore on herring and other food this time of year, she said.

The large holes under both porpoises' jaws were likely caused by gulls.

The gulls go for the animal's acoustic fat, pecking away at their jaw.

"Really nice fat lining the the jaw line," she said.

The porpoises are dark on top and white on bottom. The two colors camouflage the animals, protecting them from predators above and below, she said.

When full grown, they are about 5 feet 6 inches and weigh about 160 pounds.

The beach spectacle drew the attention of walkers and dogs Wednesday morning.

Jack Feeley of Swampscott, a retired public relations worker,  hasn't seen a beached porpoise on the Swampscott shore before. He wonders what happened to them and why they washed ashore where they did.

"I was surprised and curious," he said.

Walker James Woodbury, 64, said he has been walking King's Beach since he was 10 and has never seen a porpoise wash ashore.

Pugliares does not know whether the mammals first died in the water and then washed ashore.

Those questions may get answers after lab workers analyze tissue samples she took.

One porpoise was near the sea wall and the outfall pipe at the town line.

The other one was farther south, about a quarter-mile away.

They were stretched on the sand by bits of shell, sea glass and sea weed.

Gulls squeeled and the surf rumbled. 

Pugliares said there are usually a number of these animals that wash ashore this time of year.

The aquarium asks for the public's help if they see beached sea mammals or turtles.

"If you see a live or dead seal, porpoise, dolphin, whale or sea turtle, please call the New England Aquarium at 617-973-5247," she said.