• Otávio Santiago

New Study Fuels Debate About Source of Birds’ Magnetic Sense

A protein found in robins’ eyes has all the hallmarks of a magnetoreceptor and could help birds navigate using the Earth’s magnetic fields, according to a study published today (June 23) in Nature. The research, an intensive in vitro analysis of robin cryptochrome 4 (Cry4), revealed that the protein is magnetically sensitive and fulfills several predictions of one of the leading quantum-based theories for how avian magnetoreception might work.

The authors of the study argue that their findings support Cry4 as the likely receptor for birds’ still largely mysterious magnetic sense. But some other researchers who spoke to The Scientist say that while the results are extremely useful for understanding cryptochromes, a family of proteins often studied in circadian rhythms, the paper omits some scientific context for its findings and doesn’t necessarily support Cry4 as the elusive magnetoreceptor.

“It’s a very important step to show that this cryptochrome 4 actually can perceive light and then become magnetically sensitive,” says Rachel Muheim, a zoologist and magnetoreception researcher at Lund University in Sweden who was not involved in this work. She says that in her view Cry4 has already emerged in the wider literature as the most likely candidate in avian navigation, but “there are a number of experiments that can’t be explained” by the mechanism the new study focuses on and that aren’t addressed in the paper, she adds. “There’s a lot of unanswered questions.”

Many animals use the Earth’s magnetic fields to help them navigate, but scientists have long debated the biological mechanisms underpinning this sixth sense, with repeated accusations of irreproducible findings and sometimes heated debates between different research groups.

Please, to access the full article visit The Scientist