The African bullfrog males call out during the rainy season. The call lasts about a second and can be described as a low-pitched whoop. Males have two breeding strategies, depending on their age. Young males congregate in a small area, perhaps only 1 or 2 m2 (11 or 22 sq ft) of shallow water. The larger males occupy the center of these breeding arenas or leks and attempt to chase off other males. Often, they fight, causing injury or even killing one another. The dominant male attempts to prevent other males from breeding. A female approaches the group of males by swimming along at the surface until she is within a few meters of the group. Then the female dives to avoid the smaller males and surfaces in the defended area of a larger male in the middle of the group. This helps to ensure that she mates with the dominant male.