African or Edible Bullfrogs (Pyxicephalus edulis) spend up to 10 months of the year below the soil surface in a dormant state called aestivation. They emerge to breed after enough heavy rain has fallen to fill shallow depressions and ditches with water. The males make their deep “whoop” call that often occurs as burst of sound with several males following the lead of the first frog that calls (known as antiphonal calling). Males gather in loose congregations, and fights often break out, with dominant males charging, tossing and biting rivals. These conflicts are sometimes fatal. An explosive Bullfrog breeding event occurred near Shingwedzi Rest Camp in Kruger National Park in February 2010. Egg-laden female bullfrogs entered the water and were often chased by males before mating occurred with a successful male. In most cases mating Bullfrog pairs were left alone by other males. The larger male Bullfrog clasped the female in amplexus, and the female raised her cloaca above the water surface and began extruding eggs which were immediately fertilised by the male. After mating there were floating many mats of fertilised eggs on the surface of the claypan.