Solving The Mystery Of Why Rock Ants Avoid Right Turns

Dec 26, 2014
Originally published on February 5, 2015 1:15 am
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Delivery drivers plan their route with as many right turns as possible. Left turns - they're just a hassle. But get this - there is a species of ant that prefers left turns. And this got NPR's Richard Harris curious.

RICHARD HARRIS, BYLINE: Edmund Hunt is working toward his PhD at the ant lab at Bristol University in England. He's trying to understand how ants make decisions. He's noticed that rock ants, which usually live in rocky crevices, prefer to turn left when they enter an unfamiliar nest site. And he wondered why.

EDMUND HUNT: Maybe this is actually beneficial to the ants in terms of their exploration of mazelike environments.

HARRIS: After all, you're more likely to escape from a maze is if you turn the same direction at every junction. And if these ants tend to turn in the same direction, it could also help them regroup. But why left? Hunt's hunch, reported in biology letters, is that ants aren't as symmetrical as they appear. Their left eye may be better than the right for detecting predators.

HUNT: So if you're going into an unfamiliar, potentially dangerous space, that would seem to favor approaching it on the left.

HARRIS: A similar bias, preferring the left eye to watch for predators, has been observed in fish and lizards, Hunt says. Cockroaches prefer to turn right according to one study. So these biases aren't consistent, but they do run deep. The lesson here for people is a bit subtle - ordering on the philosophical.

HUNT: Of course we all have our biases and sometimes these are even, like, hardwired into the way that our brains work. And of course biases can be useful, can help you to survive.

HARRIS: And that's today's lesson from Temnothorax albipennis, the lowly rock ant. Richard Harris, NPR News. Transcript provided by NPR, Copyright NPR.