Near blind, subterranean, sea rats of African Ansel can feel magnetic fields with their eyes, a study found.
Native to Zambia, the animals have eyes only 1.5 mm in diameter, live in complex underground tunnel systems up to 2.8 kilometers long and feed on plant tubers and roots.
Ansell’s mole eyes barely function. They cannot see color or form sharp images and their main function is to distinguish between light and dark.
Animals usually have an innate preference to build nests in the southeastern sector of a circular arena, while other moles prefer different directions.
To find out how to orient themselves, researchers from the University of Duisburg-Essen in Germany surgically removed the eyes of a group of moles.
Initially, they tested six pairs of moles, finding that before the operation they preferred the southeast to build nests, but after the operation the activity was random. These results suggest that rodents̵
A second experiment was then performed comparing 10 mole rats with surgically removed eyes to 10 in the control group. The researchers tried four alignments of the magnetic field – those in the control group went southeast, while the other group was not biased in this direction.
It is important that the ticks do not show any other behavioral changes after the operation, the researchers write in the Journal of the Royal Society Interface.
Magnetoreception, the ability to sense magnetic fields, has been demonstrated in a number of animals, but the structure and location of magnetoreceptor cells are unclear.
Previous research has also shown that the eyes of these corpses are required to detect magnetic signals. In one experiment, when a local anesthetic was applied to the cornea of the mole’s eye, they lost their ability to orient themselves. This approach has some drawbacks, says the author of the new study, Kai Caspar, because the drug can penetrate the blood-brain barrier and cause a cascading effect on the nervous system.
Does the new study mean that Ansel’s mole rats kept their eyes – unlike their largely blind underground counterparts – because of these magnetic receptors?
The receptor in question does not appear to be positioned in a spatial order – any organ could do the job, Caspar said, noting that blind moles retain their ability to detect magnetic signals. “We still don’t know why Ansel’s ticks keep their eyes open. This magnetic reception does not seem to be the answer. “