Ants Show an Aptitude for Arithmetic!

(July 15th, 2011) Not everyone is particularly fond of figures, at least not in our human world. But it seems like ants have developed a taste for them - at least when there's syrup involved.

About a hundred years ago, a horse named Clever Hans impressed with his calculation skills. Owner, Wilhem von Osten, was convinced to have taught his equine pupil to add, subtract, multiply, divide, work with fractions and even to understand German. However, as it turned out, the horse wasn’t as mathematically inclined or as linguistically gifted as his owner had believed; nevertheless, research into the subject continued.

Over the past decades, different experiments with chimpanzees, pigeons and fish have demonstrated that mathematical abilities are not unique to human kind. Now, Zhanna Reznikova and Boris Ryabko from Novosibirisk State University, Russia have reviewed their own and other people's work to demonstrate that even insects, like ants, are as smart as a fifth grade pupil.

To study their flair for maths, ants (in their case Formica polyctena Foerster) were forced to transmit some piece of valuable information to each other. How can you force insects to transmit information? Well, Reznikova and co-workers used one ant colony of approximately 200 individuals, and different maze-like gadgets containing several branches. A dab of syrup was randomly placed in only one of them. Scouter ants were put directly on this branch, having then the task of informing the foragers, which branch of the maze they had to go to in order to find the sweet food. Amazingly, in more than 70% of the cases, the foragers found the correct branch immediately.

The investigators measured the time that the ants needed to pass the information amongst themselves. In doing so, they were able to relate the communication skills to their mathematical competence.

Using this set up, they observed that ants could estimate the number of the branch in the sequence of branches in one maze. The higher the branch number, the longer they needed to pass the information about the syrup´s hiding place. It seems that ants are able to encode and pass information about quantities; amazing, isn't it?

But Reznikova and colleagues went a step further. The second setting they used had two branches with food. The invertebrates could easily identify, which branch was the “favourite”. The branches were later changed and, again, the ants had the task of finding the syrup.

It was remarkable, how little time they took to communicate the new position of the syrup. It seemed that these little creatures were able to pass information about the difference of the positions between the “favourite” branch and the new one. Can this maybe indicate ants' ability for, albeit simple, arithmetic?

Counting, estimating, understanding quantities, simple arithmetic... that all seems pretty obvious to us humans. But to what extent are non-human individuals able to perform these mathematical tasks?

A huge range of experimental evidence tells us that, indeed, we are not the only smart ones. And now, the Russian investigators have shown that the legendary organisation of ants' colonies is not the only remarkable characteristic about these insects.

Even though the exact correlation between communication and mathematical skills are rather briefly described in this review, the experiments they carried out are fascinating.

Paola Carrillo B.

Picture: iStockphoto/Antrey

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