African Bullfrog

The African bullfrog is the biggest frog in Africa and very aggressive. But in spite of that, it’s a devoted father. Bullfrogs spawn in little pools around the margins of larger ponds and after mating is over, one male stays to keep watch over the newly hatched tadpoles. If the pool begins to dry up the dutiful dad digs a channel to a new water source:

 "An African bullfrog kept at the Pretoria Zoo in South Africa once ate 17 baby cobras."

  "In a single-sex environment, the African bullfrog can switch genders."

  "African Bullfrogs also bite when they are provoked. Its one of three frog species that have sharp teeth and bite humans when they are provoked or handled by humans."

                                                 Pyxicephalus adspersus, Boston Aquarium by Steven G. Johnson

This is a large frog, with males weighing 1.4 kg (3.1 lb), though can easily exceed 2 kg (4.4 lb); females are half the size, making it unique among frogs, as in most amphibians females are usually larger than males. Males can reach 10 inches while females only reach about 6 inches. (Wikipedia)