Marine biologists track seagoing creatures, including adult loggerheads, with satellite tags that transmit information such as location, depth and temperature. But hatchlings are too small to tag — affix a tag with heavy batteries to these turtles, and they'll sink, Mansfield said.

Advances in tag technology have started to change all that. New tags are smaller and solar-powered (no heavy batteries needed), Mansfield said. They're still too large to affix to a newborn loggerhead, but they fit on young turtles. Mansfield and her colleagues lab-reared 17 loggerhead turtles to the age of 3.5 to 9 months, waiting until the turtles had reached between 4 inches and 7 inches (11 to 18 cm) in length before tagging them and releasing them into the Atlantic Ocean.

The long-standing expectation was that baby turtles hatch off the East Coast of the United States, launch into the Gulf Stream that carries them north up the coast and then ride into the North Atlantic Subtropical Gyre. This system of currents takes the turtles past the Azores off the coast of Western Europe and down the coast of Africa, before the animals pop back out on the East Coast again.

While the turtles do use the Gulf Stream and the Gyre, they don't always complete this ring around the Atlantic, the researchers report today (March 4) in the journal Proceedings of the Royal Society B. In fact, the turtles completed quite diverse journeys; they traveled clockwise, but on their own, individual paths. Some even dropped out of the Gyre into the still waters within that circular current, known as the Sargasso Sea. The Sea gets its name, in part, from the floating Sargassum that gathers there.