Birds are famous for migration. Species ranging from ducks to hummingbirds gather in flocks in the autumn to travel to warmer climates—sometimes thousands of miles away. The arctic tern is a champion, traveling 44000 miles each year from northern Canada to the southern tip of South America, and back.
Some mammals also migrate seasonally, especially the flocks of wildebeest on the plains of Africa. Even some of our grandparents migrate from northern cities to warmer golf courses in southern Florida each winter.
But turtles? Yes, some sea turtles are among the champion migrants, traveling farther in the world’s oceans than many birds and mammals of similar size. The leatherback sea turtle travels about 7500 miles from its birthplace on subtropical beaches to areas of the open ocean areas where it feeds. Normally, females return to the beach where they were born to lay their eggs.
“What’s amazing is that they are these big and ancient animals, and their brain is the size of your index finger,” says Bryan Wallace, a scientist at the Duke University Marine Lab. “What this shows is that something as fundamental to a species survival as migration – finding the habitats you need to survive and doing so over such vast distances – doesn’t need a lot of brain power if you’re a sea turtle. Evolution has equipped them with lots of other tools to be able to migrate. And a lot of those tools are similar to those used by other migratory animals like birds – using the Earth’s magnetic field, using celestial queues.”
Where sea turtles migrate and when, is of more than passing interest. The leatherback turtle is an endangered species, and knowing when it passes through certain ocean waters helps us to recommend a schedule for fishermen, so that turtles are not inadvertently captured in their nets.
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Web Extra
Interview with Bryan Wallace, a scientist at the Duke University Marine Lab
[audio:http://wamcradio.org/EarthWise/wp-content/uploads/2013/07/wallace_web_extra.mp3|titles=wallace_web_extra]
Web Links
See Hays and Scott, in Functional Ecology,2013
Photo, taken on June 16, 2011, courtesy of USFWS via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio. Support for Earth Wise comes from the Cary Institute of Ecosystem Studies in Millbrook, NY.