of animals represent one of the great wonders of the natural world.In the marine environment, migratory movements
sometimes reach astonishing extremes: for example, some sea turtles,
sharks, and elephant seals travel distances that exceed the width of
before returning to their home areas to reproduce.How animals find their way during such migrations has remained a
central mystery of sensory and behavioral biology.
turtles are among the most impressive navigators
in the animal kingdom. As hatchlings, turtles that have never before
the ocean are able to establish unerring courses towards the open sea
maintain their headings after swimming beyond sight of land.
turtles follow complex migratory pathways that often lead across
expanses of seemingly featureless ocean. After completing their years
open sea, juvenile turtles take up residence in coastal feeding grounds
show great fidelity to their feeding sites, homing back to specific
after long migrations and experimental displacements. Similar
navigational abilities exist in adult turtles, which migrate
distances between specific feeding areas and nesting beaches.
Top left: a hatchling green
turtle (photo by Ken Lohmann, Univ. North Carolina); Top right: a juvenile
green turtle (courtesy of Univ. Central Florida turtle group); Bottom
left: Hawaiian green turtles (photo by Ursula Keuper-Bennett
and Peter Bennett; Bottom right: hatchling loggerhead turtles (photo by
The longest and most spectacular
made by young loggerhead turtles. The journey begins when the
no bigger than a child's hand, dig their way out of their underground
the beach and enter the sea. During the vast migration that follows,
travel for a period of years along migratory routes that span entire
Young loggerheads in the North Atlantic
more than 9,000 miles (15,000 kilometers) before returning to the North
American coast. Those in the Pacific travel even farther.
How can young sea turtles with no prior migratory experience guide
across an entire ocean and back? Considerable progress has been made
understanding how young loggerheads in the Atlantic
navigate. To learn about how baby loggerheads guide themselves
their first migration, follow the hatchling
Hatchlings embark on an impressive
transoceanic migration, but they do not navigate to targets more
broad oceanic regions. In contrast, older turtles acquire an
pinpoint specific geographic locations such as feeding areas and
beaches. Recent experiments have demonstrated that sea turtles
possess a remarkable ability to exploit positional information in the
magnetic field as a kind of navigational map that can be used to guide
specific goals. To
learn about this research, follow the magnetic
NOTE: If you reached this page through a
search engine and do not see a menu
of the site in a frame to the left, click here.
of the research presented in these web pages was made possible by
grants from the National Science Foundation.