How much do pigs know about geometry? Is the abstraction of a circle a uniquely human phenomenon, or does it exist in the pig's world ?
In order to find an answer to these questions "PIGCIRCLE" became one of the first major projects.
There are no mental images of circles. Rather, we know with more or less certainty that we have a circle in front of us if we see one. This knowledge is taught, as is the knowledge on how to create a circle. It is a tricky thing to teach pigs to create a circle. There is no way we could tell them to hold a pencil, connect it with a string to a central point and draw a circle around it. We have to look for a method to bridge the gap between human skills and pig skills.
PIGVISION found an ingenious solution for this problem. The Pig draws marks, too. Its natural way of leaving marks behind is by digging up the surface of the soil. Its nose is very well adapted to this task. Not only is it very strong but also it is gifted with a highly developed sense of smell. PIGVISION designed an experiment which takes advantage of the pigs natural behaviour of looking and digging up food.
In a first step, we dig up a large circle, about 20 cm deep and 6m wide, in a sandy paddock (Figure 1).
Apples and corn cobs were cut in pieces, and placed into the ditch so that a continuos string of food was offered (Figure 2 and 3).
The ditch and the food was burried again, and the paddock neatly flatened (Figure 4).
2 Pigs who where watching the procedure from outside the fenced part of the paddock were given access to the area (Figure 5).
It took the pigs about one minute to find a starting point for their digging action. Probably because of the food and the sandy soil the whole task of creating a circle was achieved in less than 20 minutes (Figure 6).
We suggest further research into this matter by subsequently interrupting the continuous string of burried food in order to see whether the pig acquires the necessary knowledge in geometry to complete a circle.