A new paper has just been released that might finally give us an answer as to why some animals have a magnetic "sixth sense," such as sea turtles that are able to return to the beach where they were born.
Despite 50 years of research, this impressive ability has had the scientific community stumped.
An innate, biological navigation tool
Animals that sense Earth's magnetic field include sea turtles, birds, fish, and lobsters. Specific species can use this ability as an impressive navigation tool, such as sea turtles that are, impressively, able to pinpoint the location of their birthplace.
"The search for a mechanism has been proposed as one of the last major frontiers in sensory biology and described as if we are 'searching for a needle in a hay stack,'" Robert Fitak, an assistant professor in UCF's Department of Biology, explained in a press release.
Fitak is part of a group of researchers, also from the United Kingdom and Israel, that has just published a study in Philosophical Transactions of the Royal Society B that proposes a new hypothesis for the mechanism.
They believe the magnetic sense comes from a symbiotic relationship with magnetotactic bacteria, a special type of bacteria whose movement is influenced by magnetic fields, including that of the Earth.
In their paper, the researchers present arguments for and against their hypothesis and also present new supportive evidence they have found. The new evidence comes from Fitak, who mined one of the world's largest genetic databases of microbes, the Metagenomic Rapid Annotations using Subsystems Technology database.
Magnetotactic bacteria in animals
Fitak specifically searched for the presence of magnetotactic bacteria that had been found in animal samples: "the presence of these magnetotactic bacteria had been largely overlooked, or 'lost in the mud' amongst the massive scale of these datasets," he explained.
Fitak found, for the first time, that magnetotactic bacteria are associated with many animals, including a penguin species, loggerhead sea turtles, bats, and Atlantic right whales.
The researchers say that it is still not known wherein these animals the magnetotactic bacteria would live, but it may well be associated with nervous tissue, like the eye or brain.
"I'm working with the co-authors and local UCF researchers to develop a genetic test for these bacteria, and we plan to subsequently screen various animals and specific tissues, such as in sea turtles, fish, spiny lobsters, and birds," Fitak said.
Though more evidence is needed before any conclusive statements can be made, learning how organisms interact with magnetic fields has the potential for a number of applications, including the potential to improve our own understanding of how we can use Earth's magnetic fields for our own navigation purposes.