By David Adams

MIAMI (Reuters) - A great white shark being tracked by marine researchers and weighing more than a ton is keeping scientists guessing after it has made its way from Massachusetts' Cape Cod to the northeast Gulf of Mexico this week.

Tagged in 2013 with a satellite tracking device, the great white known as Katharine is charting a groundbreaking map of the shark highway as scientists seek to discover its seasonal feeding grounds.

Katherine, was most recently spotted on Wednesday morning about 52 miles (84 kilometers) south of Cape San Blas in the Florida Panhandle.

But where it is headed next is unclear, according to the team of scientists tracking her.

"We just don't know. She could either turn west towards Texas or she could turn back and go out into deeper water," said Bob Hueter, part of the scientific team monitoring the movements of Katherine, as well as Betsy, another great white who was last spotted in the Gulf about 140 miles (225 kilometers) west of Sanibel island, south Florida on June 5.

The sharks already have defied expectations by staying in the warming summer waters of the Gulf, rather than heading back to the cooler seas off Cape Cod to feed on seals, said Hueter, director of the Center for Shark Research at Mote Marine Laboratory in Sarasota, on Florida's southwest coast.

Scientists have tracked the great white before in the Pacific and off Australia and South Africa, but never off the U.S. Atlantic coast, Hueter said.

Scientists knew that great whites came to Florida and frequented the Gulf of Mexico. But exactly how they got there was a mystery until Katharine, a young 14.5-foot (4.4-meter) and 2,300-pound (1,040-kilograms) shark, showed the way.

She can be tracked when she comes to the surface so that the device on her dorsal fin pings data points to the researchers, though those moments are unpredictable as sharks spend most of the time underwater.

"It's a like a teenager that doesn't call home as often as it should," Hueter said.

Katharine's travels, and those of other great whites tagged by Ocearch, a non-profit group that researches the top predators in the marine food chain, can be followed on Ocearch’s interactive tracking maps at