Summer is almost here, and with the return of the warn weather comes the return of the pests that I fight every year. Ants!
We’ve set up traps, though they aren’t gone yet. With a little bit of luck they will learn to avoid the indoors. With all this in mind, it becomes a little difficult to hear that ants are able to count.
How do we know that ants are able to count? In 2006 a trio of German and Swiss scientists, Wittlinger, Wehner, and Wolf, published the results of an experiment they performed on the Tunisian dessert ant. They noticed that when an ant is searching for food it travels in an apparently random zig-zag pattern, but once a food source is found the ant is some how able to walk directly back to their nest, despite sometimes being 50 meters away. Here is an excerpt from their abstract:
Here we test the hypothesis that navigating ants measure distances traveled by using some kind of step integrator, or “step counter.” We manipulated the lengths of the legs and, hence, the stride lengths, in freely walking ants. Animals with elongated (“stilts”) or shortened legs (“stumps”) take larger or shorter strides, respectively, and concomitantly misgauge travel distance. Travel distance is overestimated by experimental animals walking on stilts and underestimated by animals walking on stumps.
So there is evidence that ants can somehow instinctively count the number of steps they have taken, and use that information to compute the direction of home.
Meanwhile there are human societies that survived until the 20th century, apparently without the ability to count.
What are some other amazing feats of mathematics that living beings are able to do instinctively?