In the last month, 177 dolphins have been stranded on Cape Cod beaches, but researchers are at a loss to explain what's driving the dolphins into shallow muddy waters in record numbers.
So far, 124 dolphins have died, the Associated Press reports.
One group of 11 dolphins turned up in a remote inlet down Wellfleet's Herring River, were they have become stranded in grayish-brown muck that is hard for rescuers to reach, the AP reports.
One of the dolphins has already died, but the other 10 appeared healthy as they struggled to get free this week.
Rescuers from the International Fund for Animal Welfare, wearing orange vests and waders, carried dolphins in slings out to deeper water and tried to herd them in the right direction, the AP says.
Along the 35-mile stretch of the Cape's interior coastline from Barnstable to Wellfleet, WHDH TV notes, the difference between the rise and fall of the tide can be as much as 13 feet. Dolphins arrive in what looks like safe water, but are quickly trapped as the tide rushes out.
"Once they're in the bay they can't always find their way out and we think that's a big part of it," Katie Moore of the IFAW tells WHDH.
Researchers are mystified as to why five times as many dolphins as usual have been stranded on Cape Cod this year. Theories range from changes in weather, water temperature or behavior of the dolphins' prey.
