The Common Warthog (Phacochoerus africanus) is found across much of sub-Saharan Africa. Its common name is derived from the three pairs of facial "warts" made of fibrous tissue of different shape and thickness that are evident on the muzzle, along the jaws, and under the eyes (warts and tusks are less developed in females). These structures are also present on the very similar Desert Warthog (P. aethiopicus), although the shape is somewhat different.
Common Warthogs are the only African pigs that are typical open country species, as evidenced by characteristic grazer morphology and behavior. Although they are largely grazers, their diet is not limited to grass, including, for example, roots, fruit, and small mammals, reptles, and birds when available. They are generally limited to various types of savanna grasslands, open bushlands, and woodlands, usually not far from a reliable water source.
Common Warthogs usually trot with the head held high and the back rigid. They are highly diurnal, going underground before dark to sleep in abandoned burrows of Aardvarks (Orycteropus afer) or other animals, often backing in. Humans, Lions (Panthera leo), Leopards (Panthera pardus), crocodiles, and hyenas are the main predators, but Cheetahs (Acinonyx jubatus) and African Wild Dogs (Lycaon pictus) can take small warthogs. Female warthogs are notoriously fierce in protecting their young. Warthogs have been observed allowing Banded Mongooses (Mungos mungo) and ground hornbills (Bucorvus spp.) to groom them to remove ticks.
Expansion of the Sahel has resulted in the contraction of the Common Warthog's historical range in the north. In the past, rinderpest epidemics took a significant toll on warthog populations in some areas.
(Meijaard et al. 2011 and references therein)