Science Corner: Of Rats, Roaches and Men

Academic life regularly involves travel to new cities. Most common are the conferences; the information superhighway can connect people in lots of ways, but some actual face time with peers, colleagues, friends and mentors within one’s discipline is still valuable. (Speaking of which, if you are in the sciences you’ll want to know about ESN’s presence at the upcoming American Scientific Affiliation conference.) One of my favorite parts of a conference is the simple pleasure of walking around a different city. I’ll usually look at a map to pick out some possible destinations of interest, then set out and just see what I can see. Although it happens every time, I’m still kind of pleased and amazed that I wind up knowing my way around, at least for a few blocks around the hotel or conference center. True, the human tendency to arrange cities in grids helps, and there is often a river or ocean or other notable body of water to help provide orientation. Still, I think it’s nifty how well our brains can internalize all that spatial information and navigate from it.

If it sounds like I’m bragging about my own particular spatial acuity, rest assured biology keeps me humble. Plenty of animals are good navigators also. We’ve known for a while that rats have many of the same faculties as we do for orienting themselves to their immediate surroundings. A recent study suggests roaches have comparable perceptions of their surroundings and their place within them. For example, they seem to be able to integrate visual cues and internal sensory information to sense which way they are facing relative to their surroundings, just as we do. That doesn’t necessarily mean they know absolute north and south or east and west, just as such concepts are not innate to humans. Rather, if they turn 180 degrees, they have some sense of how much to turn to get back the way they were originally facing, and similar orientation tasks. That probably seems pretty basic; the point here is not just that they can accomplish such tasks, but also that they seem to do so in a similar way to us.

The linked news item refers to this spatial sense as a “GPS” and while I can appreciate the appeal of the analogy, it seems a bit off to me. What was actually studied was purely local spatial awareness, orientation with respect to visible objects. Animals and humans have been doing that for ages without the aid of satellite networks. The global aspect of GPS seems like a significant difference; long range navigation relies on additional faculties. Still, there are plenty of examples of animals that also have those skills. I had the opportunity to discuss how birds and beetles manage to not get lost on long trips for Christianity Today’s The Behemoth last week. You might enjoy that piece as a complement to this one.

In fact, birds may actually be able to see those magnetic fields. There is a light-sensitive protein in the eyes of birds that reacts to magnetic fields in a way that could generate a nerve signal. Since that signal would be carried to the bird’s brain by the optic nerve, it would likely be perceived visually. We may never know exactly what magnetic fields look like to birds, but I imagine a version of what you or I see enhanced with something like an extra color.