ssp. africanus (Northern Savanna and Sahel region), aeliani (Eritrea, Djibouti, and north Somalia), massaicus (central and eastern Africa), sundevallii (southern Africa)
Status: Least Concern
Did you know? Common warthogs are the only African pig that are typical open-country species, with morphological and behavioural adaptations typical to grazers.
Subspecies and distribution
P. a. africanus Gmelin, 1788 – Northern Savanna and Sahel region, from Mauritania to Ethiopia.
P. a. aeliani Cretzschmar, 1828 – confined to Eritrea, Djibouti, and N Somalia.
P. a. massaicus Lönnberg, 1908 – E and C Africa, from N Uganda and S Kenya, E and S Democratic Republic of Congo, Rwanda, Burundi, Zambia, Malawi, Tanzania and N Mozambique.
P. a. sundevallii Lönnberg, 1908 – southern Africa, including SW Angola, N Namibia, N Botswana, Zimbabwe, Botswana, S Mozambique and parts of South Africa.
Head-body: 125–150 cm (males), 105–140 cm (females), tail 35–50 cm, weight 60–150 kg (males), 50–75 kg (females). This is a pig with long legs and short neck. Proportionally it has a massive head with broad and flattened muzzle and snout, and prominent curved tusks flaring upwards. The upper tusks measure an average 25–30 cm in length in adult males (record: 60 cm) whereas the lower tusks are only 13 cm. The greyish body is barrel-shaped with a hairless skin that can take on differing hues of grey or brown depending on the color of the soil in its holes or wallows. A dorsal mane of yellowish to jet black hairs is longest on the shoulders and neck. A narrow, tufted tail is held vertically when trotting. In many individuals, whitish bristles on the lower jaw form conspicuous “sideburns”. Three pairs of facial “warts” of different shape and thickness, made of fibrous tissue, are situated on the muzzle, along the jaw, and under the eyes. In males, the infraocular warts can grow up to 15 cm and have a protective function. They can take on various orientations, but are always conical; only the Desert Warthog P. aethiopicus displays curled down jugal warts. Warts are less developed in females, as well as tusks and preorbital glands. Common Warthogs usually trot in a quick, springy stride, with the head held high and the back rigid. When grazing or rooting, they often drop on their “knees” instead of stretching their short neck. Callosities characteristic of carpal joints on forelegs are observed on embryos, which provide arguments in favour of evolutionary theories on “anticipatory” adaptation or on the heredity of acquired characters. Females have four pairs of mammae. Dental formula: I 1/3, C 1/1, P 3/2, M 3/3 for a total of 34 teeth. Whereas Desert Warthog is characterized by an absence of functional incisors, Common Warthogs always has two upper incisors and usually six functional lower incisors as in the adult dentition of the normal swine form.
Common Warthogs are the only African pig that are typical open-country species, with morphological and behavioral adaptations typical to grazers. Generally they are confined to various types of savanna grasslands, open bushlands and woodlands, usually within range of perennial surface water. Although usually absent from forests, thickets, cool montane grasslands, deserts and steppes, Common Warthogs are present in aridlands near the Danakil desert and Bale Mountains forests (Ethiopia) and in Djibouti forests (see photo to the right). Abundance of Common Warthogs is probably linked to the availability of Aardvark (Orycteropus afer) holes, as they need deep burrows for protection from predators as well as from fluctuations in temperature and humidity. While their body can obviously sustain a certain tolerance range, they cope with high temperature by sheltering into shade, wallowing and/or dust-bathing. Piglets are particularly vulnerable to cold and malnutrition during drought, which, together with predation and other factors, account for over 50% mortality rate during the first year.
Common Warthogs have an omnivorous diet composed of grasses, roots, fruits, bark, fungi, eggs, carrions, as well as small mammals, reptiles and birds. The diet varies with seasonal availability of food items, although the species is very selective. Areas with abundant food resources like bulbs, rhizomes and nutritious roots can sustain large temporary congregations of animals. This opportunism and dietary versatility account for Common Warthogs successful survival strategy. They are powerful diggers, using both snout and hooves, but not tusks. When feeding, they often move around walking on their anterior knuckles with their hindquarters raised. They use their incisors to wrench grass stems or strip seedheads, and they excavate rhizomes and mineral-rich earth with the hard edge of their snout.
Common Warthogs are highly diurnal. They go underground before dark and sleep in abandoned burrows of aardvarks or other animals. Males enter last and commonly reverse in, with the head facing the opening, and ready to fight an intruder or rush out as needed. To a certain extent, season and weather dictate their daytime activity; it includes a range of typical occupations like feeding, drinking, wallowing, rubbing against trees or termite mounds, and grooming. Feeding occurs mainly in early morning and late afternoon, but they graze also between irregular resting periods in the shade of bushy thickets or in mud wallows. Humans, lions, leopards, crocodiles, and hyenas are the main predators, but cheetahs and wild dogs are also capable of catching small warthogs. Females are extremely aggressive and courageous when defending their piglets. It had been reported that Common Warthogs have inflicted deep and deadly wounds in lions. Common Warthogs have been observed allowing banded mongooses and ground hornbills to groom them to remove ticks.
Movements, home range and social organisation
On average, sounders move a distance of 7 km per day, and visit the same areas at about the same time. Their home range averages 174 ha (min. 64–max. 374) and both males and females tend to remain close to their natal area. Typical densities range between 1 and 10 per km² in protected areas, but local densities of up to 77 per km² were found on short grass in Nakuru National Park, Kenya. The social structure of Common Warthogs is one of small groups: solitary males or bachelor groups (45% of the population), matriarchal groups consisting of adult females with juveniles and/or yearlings, or yearling groups. Boars accompany sounders when females are in oestrous. Females are temporarily on their own at farrowing time, but they commonly join up with other females and their young. Bonds between adult females and between mothers and daughters can be stable and last over several breeding cycles.
Both sexes reach puberty at 18 months. During the rut, boars locate oestrous females by visiting burrows. Male fights consist in frontal-pushing, interlocking tusks, and hitting the opponent in the face or in the flanks. The mating system is promiscuous with males roaming and mating with numerous females, and females mating with more than one male. Where seasons are marked, breeding is seasonal with females usually coming into oestrus early in the dry season and farrowing at the beginning of the rainy season. Non-offspring nursing occurs. Gestation is 160–170 days and average litter size is 2–3 (range: 1–8).
Status and conservation
The species is not listed on CITES Appendices. Common Warthogs are classified as Least Concern on The IUCN Red List. Common Warthogs occur in most protected areas in savanna zones. Expansion of the Sahel has resulted in a contraction of its range in the north and accounts for its rarefaction in Mauritania and Niger. Because of their susceptibility to drought and predation, populations may easily be prone to local extinction. In the past, populations were greatly reduced by rinderpest in some countries.
Text adapted from: Meijaard, E., J. P. d'Huart, and W. L. R. Oliver. 2011. Family Suidae (Pigs). Pages 248-291 in D. E. Wilson, and R. A. Mittermeier, editors. Handbook of the Mammals of the World. Vol 2. Hoofed Mammals. Lynx Edicions, Barcelona, Spain.
Child, G., Sowls, L. and Mitchell, B.L. (1965). Variations in the dentition, ageing criteria and growth patterns in warthog. Arnoldia (Rhodesia) 1: 1-23.
Clough, G. and Hassam, A.G. (1970). A quantitative study of the daily activity of the warthog in the Queen Elizabeth National Park, Uganda. East African Wildlife Journal 8:19-24.
Cumming, D.H.M. (1975). A field study of the ecology and behaviour of warthog. Museum Memoir No. 7, National Museums & Monuments of Rhodesia, Salisbury. 179pp.
Cumming, D.H.M. (2008). Phacochoerus africanus. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.2. Downloaded on 07 March 2010.
Cumming, D.H.M. (2013). Phacochoerus africanus Common Warthog; pp 54-60. in: Kingdon, J. & Hoffmann, M. (eds) 2013. Mammals of Africa: Volume VI. Pigs, Hippopotamuses, Chevrotain, Giraffes, Deer and Bovids. Bloomsbury Publishing, London.
Deribe, E., Bekele, A. & Balakrishnan, M. (2008). Population status and diurnal activity patterns of the common warthog (Phacochoerus africanus) in the Bale Mountains National Park, Ethiopia. International Journal of Ecology and Environmental Sciences 34: 91-97.
Estes, R. (1991). The Behavior Guide to African Mammals. Berkeley and Los Angeles. The University of California Press. 218-221.
Grubb, P. (1993). The Afrotropical Suids Phacochoerus, Hylochoerus, and Potamochoerus. Pp. 66-75 in Oliver W.L.R. (ed.) Pigs, Peccaries and Hippos. Status survey and conservation Action Plan. IUCN. Gland, Switzerland.
Kingdon, J. (1997). The Kingdon Field Guide to African Mammals. London and New York: Academic Press and Natural World.
Künzel, T., Rayaleh, H.A. & Heckel, J.-O. (2004 ). Warthogs of Djibouti. Suiform Soundings 4: 55-57.
Muwanika, V.B., Nyakaana, S., Siegismund, H.R. & Arctander, P. (2007). Population genetic structure of the common warthog (Phacochoerus africanus) in Uganda: evidence for a strong philopatry among warthogs and social structure breakdown in a disturbed population. African Journal of Ecology 45: 22-30.
Radke, R. (1991). Monographie des warzenschweines (Phacochoerus aethiopicus). Bongo, Berlin 18: 119-134.
Somers, M.J. (1997). Activity patterns and activity budgets of warthogs (Phacochoerus aethiopicus) in the eastern cape province, south africa. African Journal of Ecology 35: 73-79.
Somers, M.J., Rasa, O.A.E. & Penzhorn, B.L. (1995). Group structure and social behaviour of warthogs Phacochoerus aethiopicus. Acta Theriologica 40: 257-281.
Treydte, A.C., Bernasconi, S.M., Kreuzer, M. & Edwards, P.J. (2006). Diet of the common warthog (Phacochoerus africanus) on former cattle grounds in a Tanzanian savanna. Journal of Mammalogy 87: 889-898.
Treydte, A.C., Halsdorf, S.A. , Weber, E. & Edwards, P.J. (2006). Habitat use of warthogs on a former cattle ranch in Tanzania. Journal of Wildlife Management 70: 1285-1292.
Vercammen, P. & Mason, D.R. (1993). The warthogs (Phacochoerus africanus and P. aethiopicus). Pp. 75-84, in Oliver W.L.R. (ed.) Pigs, Peccaries and Hippos. Status survey and conservation Action Plan. IUCN. Gland, Switzerland.