Movie 1.

Illustration of the experimental procedure to determine the effect of the substrate slope on ball rolling behavior. A flat surface was horizontally aligned. The dung beetles started rolling their dung balls across the surface in an individually selected direction. Once they reached a linear distance of 20 cm from the starting point, the individual was picked up and the trial was terminated. Successful runs, where the beetle reached to the edge of the arena without losing control, are indicated by black dots.