Sea Turtles and Magnetic Field Navigation

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If it ever comes up in the workplace break room, there is a simple way to tell the difference between a turtle and tortoise. (Well, except for the little detail that all tortoises are considered turtles, but not the other way around.) There are other distinguishing characteristics, but turtles live mostly in or around water, and tortoises live on land.

The more we learn, the more fascinating nature becomes. Critters are created with specialized traits. Like several others, sea turtles migrate by tuning into Earth's magnetic field. New research takes this trait even further.

Juvenile green sea turtle, Flickr / Silke Baron (CC BY 2.0)
Loggerhead sea turtles calculate longitude for use in migration. They can remember certain geomagnetic locations, an ability unique to these creatures. Another benefit is that they can find their way back to nesting locations — even after several years. The specified complexity of the mechanisms involved gives Darwin the sads. They also testify of the brilliance of the Creator.
Many different animals use the Earth’s magnetic field to navigate when migrating. Because of their impressive long-distance migration, birds are probably the animals best known for their feats of navigation, including the use of a magnetic compass. Sea turtles also well known for impressive navigation and migration.

The magnetic field has three components — declination (angle relative to true north), inclination (angle relative to horizontal), and intensity (field strength). The inclination angle points straight down at the North Pole, is horizontal at the equator, and points straight up at the South Pole. All of the magnetic field components vary geographically. Unlike latitude, there is no regular variation in the Earth’s magnetic characteristics with longitude, which means there is no simple relationship between the detected field and the actual longitude. A simple compass only detects horizontal direction.

The rest of the article is located at "Sea Turtles and Their Trusty Magnetic Compass."