A True Sixth Sense?
In grade school, we learned about the five senses. Taste, smell, hearing, sight and touch are familiar to us all. After all, we use them every day. Those of you who paid attention in high school biology may even remember some of the details about the nerves and structures that allow us to gather detailed information about the world and make sense of it in the brain.
Occasionally, we hear about a mysterious “sixth sense;” a sort of heightened intuition, or a supernatural ability to perceive information beyond the reach of the ordinary senses. Of course, most credible scientists dismiss the existence of these elusive “extrasensory” abilities.
But did you know that serious scientists have discovered an authentic candidate for a previously unknown sixth sense? It’s true. This sense has nothing to do with gazing into a crystal ball. But it’s definitely mysterious. And a little spooky.
It all began with birds. Scientists have wondered for decades how birds are able to navigate across vast distances during annual migrations. It seemed likely that they rely on senses other than the conventional ones to fly thousands of miles, year after year, from point A to point B, without fail. The Earth’s magnetic field lines seemed a possible candidate. Perhaps these amazing creatures are able to perceive magnetic fields, enabling them to fly true even in the dark, or under heavy cloud cover.
And that’s exactly what they do. They sense the Earth’s magnetic field. But how? By using an ancient type of protein that’s found in virtually all plants and animals: a cryptochrome.
Ritz T, Wiltschko R, Hore PJ, Rodgers CT, Stapput K, Thalau P, et al. Magnetic compass of birds is based on a molecule with optimal directional sensitivity. Biophys J. 2009 Apr 22;96(8):3451-7. doi: 10.1016/j.bpj.2008.11.072.