Loggerhead turtle homes in on nests magnetically
Mother turtles find their way back to nesting beaches by looking for unique magnetic signatures along the coast, according to a new study published in Current Biology.
Loggerhead turtles, for example, leave the beach where they were born as hatchlings and traverse entire ocean basins before returning to nest, at regular intervals, on the same stretch of coastline as where they started. How the turtles accomplish this natal homing has remained an enduring mystery until now.
Turtles are long lived, and females undertake reproductive migrations periodically throughout their adult lives. Thus, the population of turtles that migrate to a given beach to nest each year consists of two subsets: a group of first-time nesters, and another, typically larger group of older “re-migrants” that have nested in the area during previous years.
Loggerhead turtles are thought to reach adulthood when they are between 23 and 29 years old. Much younger than this they return to coastal areas from the open sea and continue to mature there.
Sea turtles likely go to great lengths to find the places where they began life because successful nesting requires a combination of environmental features that are rare: soft sand, the right temperature, few predators, and an easily accessible beach.
“The only way a female turtle can be sure that she is nesting in a place favorable for egg development is to nest on the same beach where she hatched,” Brothers says. “The logic of sea turtles seems to be that ‘if it worked for me, it should work for my offspring.'”http://news.scubatravel.co.uk/loggerhead-turtles-home-nests-magnetically.html #turtle