The Surprising Importance of This Adorable Sea Turtle Dance
Sea turtles are capable of creating GPS-like magnetic maps to guide them back to foraging grounds, and they do a little dance when they recognize those spots
If you’re enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
Scientists have known for decades that sea turtles utilize Earth’s magnetic field to orient themselves in certain directions as if they have a built-in magnetic compass. But accurately navigating back to a specific location requires knowing not just the direction in which they are traveling but also the precise coordinates they are heading to. Some scientists have theorized that sea turtles are capable of learning specific magnetic coordinates of foraging grounds and nesting beaches.
To put the idea that they can create a mental magnetic map of important locations to the test, Goforth and her colleagues collected several on an island off North Carolina. (The turtles were returned to the wild the following summer.) In the lab, the turtles were placed in buckets that were hooked up to a magnetic coil system; running an electric current through the system created a magnetic field in the bucket. The scientists calibrated these fields to replicate the magnetic conditions of various locales along the Eastern Seaboard, such as spots in the Gulf of Mexico or along the coast of Maine.
The scientists discovered that, even with no food actually present, the sea turtles displayed their dancing behavior when they encountered the magnetic conditions that were associated with past feedings. This supports the notion that these animals can learn the magnetic coordinates of foraging locations. A similar ability has also been observed in salmon as they venture to and from oceanic feeding grounds. (As to why they dance, Goforth says they just “get really excited in any situation when you’re giving them food like that.”)
According to Goforth, these turtles can probably remember magnetic coordinates for several years or even decades. “In the wild, they retain feeding information from when they are hatchlings to adults, which is a 20-year time span,” she says.
Goforth and her colleagues also wanted to determine if the sea turtles’ magnetic mapping capabilities were linked to their internal magnetic compass. The researchers ran similar experiments but added radiofrequency waves, which disrupted the animals’ ability to orient themselves via magnetic fields. They discovered that the turtles could still recognize specific magnetic coordinates.
The findings suggest that sea turtles possess two distinct senses for detecting magnetic fields. Past work has suggested that some songbirds and newts also possess dual magnetoreception systems. Because birds and amphibians are only distantly related to sea turtles, Goforth and her colleagues think that magnetic compasses and maps might be a common feature in the vertebrate travel toolbox.
Jack Tamisiea is a science journalist based in Washington, D.C., who covers natural history and the environment. Follow Tamisiea on Twitter @jack_tamisiea
Source: www.scientificamerican.com