A new paper in Philosophical Transactions of the Royal Society B may explain why some animals, including birds, fish and lobsters, are able to sense the Earth’s magnetic fields. It allows sea turtles to return to the beach where they were born. Researchers hypothesize that this ability comes from a symbiotic relationship with magnetotactic bacteria that are influenced by magnetic fields, including the Earth’s.

In support of this theory, Robert Fitak, assistant professor at the University of Central Florida Department of Biology and co-author of the paper, drew from one of the largest genetic databases of its kind, the Metagenomic Rapid Annotations using Subsystems Technology, to identify the presence of these magnetotactic bacteria in animal samples. The researchers are working to develop a genetic test to help with further study. They have not yet identified exactly where the bacteria live in the animals, although they theorize that it could be associated with nervous tissue like the eye or brain.

Learning how organisms interact with magnetic fields could facilitate our use of them for navigation, while also understanding how human modifications of magnetism—such as constructing power lines—might be affecting biodiversity. This knowledge may also help develop therapeutic drug delivery systems.