African Bullfrogs are the second largest frog in the world with males reaching lengths of over 20cm and weighing upwards of 1kg! They are typically found in open grasslands and savannahs at low altitudes in most sub-Saharan African countries. African Bullfrogs are extremely resilient and adaptable being able to survive in very harsh conditions.
The breeding season occurs in summer where males congregate in large groups to attract a female. The bigger males bite and attack smaller males and will sometimes even eat them! Once a big male has established his position in the centre of the group, he will begin calling for a female. Their call is a very low pitched ‘who-ooop.’ Mating will occur shortly after the female finds the male and up to 4000 eggs will be laid. Unlike most amphibians, the male African Bullfrog will watch over and protect the eggs and tadpoles. The tadpoles will metamorphosize after 3 weeks and many of them will be eaten by the male.
African Bullfrogs are carnivorous and have teeth located on the roof of their mouth. On the lower jaw they have “odontodes” which are sharp, tooth-like projections. They will sit, submerged in water, with only their snout exposed, waiting to ambush prey. African Bullfrogs will eat anything that they can overpower. This includes insects, small fish, other amphibians, reptiles and even small rodents and birds! African Bullfrogs fall prey to predators such as monitor lizards and large birds such as storks. In certain areas populations have been decimated by humans who catch them to consume.
Perhaps one of the most impressive facts about these incredible amphibians is their ability to survive through dry winters and droughts. Adults will burrow underground using metatarsal tubercles on their rear legs. In these burrows they ‘shed’ off several layers of skin cells to create a tough waxy cocoon around their body. This cocoon contains their moisture preventing them from dehydrating. In order to make it through the long dry season, they go into a state of dormancy called estivation. During this time the majority of their bodily functions shut down to reserve energy.
African Bullfrogs are definitely an extremely impressive animal and although hard to see, it’s definitely something worth keeping an eye out for on your next African safari.