July 13, 2023 — Every now and then, small groups of endangered North Pacific loggerhead turtle hatchlings swim from Japan to the coastal waters of Baja Mexico and California, a journey of nearly 8,000 miles that has mystified scientists for decades.
The crux of the mystery is not how loggerheads find their way: Scientists believe they navigate the globe using Earth’s magnetic fields, as do salmon, elephant seals, some species of shark, and other turtle species. Rather, experts have puzzled over how these young, tropical, temperature-sensitive turtles manage to cross a deep-ocean zone that’s cold enough to be nearly impassable for most creatures.
“They go past the point of no return and head toward Baja, when most of the other turtles turn back,” said Stanford marine ecologist Larry Crowder. Now, an international team of scientists has released from a ship on the high seas 25 satellite-tagged turtles in an experiment that could confirm or modify the leading explanation for how they do it. Three more cohorts are planned for release over the next four years, for a total of 100 tagged turtles.