Young loggerhead turtles swim into oncoming ocean currents rather than drifting along. The authors of a new study suggest that the turtles likely use multiple sensory cues that enable them to orient and offset displacement due to wind and ocean currents.
Despite good swimming abilities, juvenile loggerhead turtles are thought to drift passively for a significant portion of their existence on the high seas
However, a study by researchers from National Oceanic and Atmospheric Administration has found that turtles were swimming against the prevailing current in a statistically significant pattern at a rate of 30 cm/sec, which indicates an ability to detect the current flow and orient themselves to swim into the current flow direction.
The authors suggest that the turtles likely use multiple sensory cues that enable them to orient and offset displacement due to wind and ocean currents.
The 42 turtles swam in a variety of directions with some tendency for either a southwest or southeast direction. However, several turtles ventured north, with one of the longest tracks to the northwest before transmission ceased in the vicinity of French Polynesia.
One remarkable trajectory went to the southwest and passed through Bass Strait between Australia and Tasmania before transmission ceased.
This study provides (...) compelling evidence that these turtles are able to resist such transport using some mechanism not yet fully understood.
—Dr. Donald Kobayashi, National Oceanic and Atmospheric Administration