More than 100 dolphins stranded in shallow water off Cape Cod, Mass.

More than 100 Atlantic white-sided dolphins are stranded in shallow water off Cape Cod, Mass., in what one non-profit animal protection group called the “largest single mass stranding event in our response history.” Photo courtesy of the International Fund for Animal Welfare
More than 100 Atlantic white-sided dolphins are stranded in shallow water off Cape Cod, Mass., in what one non-profit animal protection group called the “largest single mass stranding event in our response history.” Photo courtesy of the International Fund for Animal Welfare

June 29 (UPI) -- More than 100 Atlantic white-sided dolphins are stranded in shallow water off Cape Cod, Mass., in what one nonprofit animal protection group called the "largest single mass stranding event in our response history."

At least 10 of the mammals had died by the time rescue efforts began Friday in the town of Wellfleet, Mass.

Others were stranded in extremely shallow water or were entirely exposed in the mud in an area known as the Great Island at the Herring River.

At least 10 of the mammals had died by the time rescue efforts began Friday in the town of Wellfleet, Mass., while others were stranded in extremely shallow water or were entirely exposed in the mud in an area known as the Great Island at the Herring River. Photo courtesy of the International Fund for Animal Welfare
At least 10 of the mammals had died by the time rescue efforts began Friday in the town of Wellfleet, Mass., while others were stranded in extremely shallow water or were entirely exposed in the mud in an area known as the Great Island at the Herring River. Photo courtesy of the International Fund for Animal Welfare

"Our valiant marine mammal rescue team is in the midst of what may be the largest single mass stranding event in our response history. 125 Atlantic white-sided dolphins stranded this morning in Wellfleet in an area called the Herring River Gut - the epicenter of mass strandings," the nonprofit International Fund for Animal Welfare said in a statement.

"At leasleast to herd the dolphins back out to deeper waters."

The non-profit International Fund for Animal Welfare was also using the rising tide to its advantage late Friday as it worked to rescue the animals. Photo courtesy of the International Fund for Animal Welfare
The non-profit International Fund for Animal Welfare was also using the rising tide to its advantage late Friday as it worked to rescue the animals. Photo courtesy of the International Fund for Animal Welfare

The group was also using the rising tide to its advantage late Friday as it worked to rescue the animals, which can grow up to 9.2 feet in length and weigh up to 510 pounds.

The large size was making the situation challenging for rescuers.

Atlantic white-sided dolphins can grow up to 9.2 feet in length and weigh up to 510 pounds. Image courtesy of National Marine Fisheries Service
Atlantic white-sided dolphins can grow up to 9.2 feet in length and weigh up to 510 pounds. Image courtesy of National Marine Fisheries Service

Estimates put the global population of the Atlantic white-sided dolphins at around 100,000. The species is normally found in warmer parts of the North Atlantic Ocean, according to the U.S. National Marine Fisheries Service.

The name is attributed to a distinctive white stripe on the dolphins' sides.

in the United States, Atlantic white-sided dolphins typically roam North Carolina to Maine, preferring to remain in temperate waters. Photo courtesy of National Marine Fisheries Service
in the United States, Atlantic white-sided dolphins typically roam North Carolina to Maine, preferring to remain in temperate waters. Photo courtesy of National Marine Fisheries Service

In the coastal United States, the dolphins typically roam North Carolina to Maine.

The animals are protected under the Marine Mammal Protection Act.