Animal Diversity Web

Ge­o­graphic Range

Desert warthogs are found in the Horn of Africa, in cen­tral and east­ern Kenya, west­ern So­ma­lia, and south­east­ern Ethiopia. They were also known from South Africa, but are now ex­tinct there. (d'Huart and Grubb, 2001)

• Biogeographic Regions
• ethiopian
  • native

Habi­tat

Desert warthogs are pri­mar­ily a sa­van­nah species, though they have higher tol­er­ance for dry con­di­tions than com­mon warthogs, Pha­co­choerus africanus, and so can live in more arid and desert-like con­di­tions. They gen­er­ally stay away from heav­ily forested zones and areas with thick un­der­growth. Most of their graz­ing area is at low el­e­va­tions as they have a low tol­er­ance to cold. Pha­co­choerus aethiopi­cus is cur­rently a trop­i­cal species, though pop­u­la­tions that are now ex­tinct may have ex­tended into tem­per­ate zones. (Estes, 1991; King­don, 1979)

• Habitat Regions
• tropical
• terrestrial

• Terrestrial Biomes
• desert or dune
• savanna or grassland
• scrub forest

• Range elevation

  0 to 1000 m

  0.00 to 3280.84 ft

• Average elevation

  300 m

  984.25 ft

Phys­i­cal De­scrip­tion

At over 1 m long and gen­er­ally more than 0.5 m tall at the shoul­der, desert warthogs are large. They have a stocky build and a large, some­what flat­tened head. There is sig­nif­i­cant sex­ual di­mor­phism, males are sig­nif­i­cantly larger than fe­males. The char­ac­ter­is­tic "warts" that give Pha­co­choerus species their com­mon name also dif­fer be­tween the sexes; males have much larger and more pro­tru­sive warts, which are paired masses of dense fa­cial tis­sue. Males also have larger tusks (elon­gated ca­nine teeth) than fe­males. Ju­ve­nile desert warthogs are like adults, but smaller with much re­duced "warts" and no tusks. Tusks grad­u­ally ap­pear after the onset of pu­berty. Most desert warthogs are brown to dark brown with short and sparse hairs cov­er­ing much of the body. A crest of much longer hair runs along the back of the neck of males and fe­males. A por­tion of this crest is some­times whitish in color. (d'Huart and Grubb, 2001; Estes, 1991; King­don, 1979; Randi, et al., 2002)

The clear­est mor­pho­log­i­cal trait that sep­a­rates desert warthogs from com­mon warthogs (Pha­co­choerus africanus) is the lack of func­tional in­cisors. These two species are quite dis­tinct ge­net­i­cally and com­mon warthogs are usu­ally slightly larger than desert warthogs. Desert warthogs are dis­tin­guish­able from closely re­lated bush­pigs (Pota­mo­choerus por­cus) and giant hogs (Hy­lo­choerus mein­ertzha­geni) by their dis­tinc­tive fa­cial warts and larger tusks. (d'Huart and Grubb, 2001; Estes, 1991; King­don, 1979; Randi, et al., 2002)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger
• sexes shaped differently
• ornamentation

• Range mass

  45 to 130 kg

  99.12 to 286.34 lb

• Average mass

  75 kg

  165.20 lb

• Range length

  100 to 145 cm

  39.37 to 57.09 in

• Average length

  125 cm

  49.21 in

Re­pro­duc­tion

Dur­ing the mat­ing pe­riod, fe­male desert warthogs uri­nate quite fre­quently, up to 10 times more than males. Male warthogs can smell the urine from a sig­nif­i­cant dis­tance and will in­ves­ti­gate the urine to de­ter­mine fe­male re­pro­duc­tive state. Dur­ing es­trus fe­males se­crete a dis­charge from the vulva which changes the color of her hindquar­ters. The act of cop­u­la­tion lasts from 1 to 10 min­utes, gen­er­ally fol­lowed by the sep­a­ra­tion of the cou­ple. Fe­males and boars (males) mostly live in sep­a­rate groups, but these groups in­ter­act more fre­quently and can even tem­porar­ily join in the mat­ing sea­son. Males and fe­males may have sev­eral mates dur­ing a mat­ing sea­son, but fe­males stop mat­ing when they be­come preg­nant. (De­lany and Hap­pold, 1979; Estes, 1991; King­don, 1979)

• Mating System
• polygynandrous (promiscuous)

The tim­ing of desert warthog mat­ing is in part de­ter­mined by cli­mate. They in­habit areas with dis­tinct dry and rainy sea­sons and tend to breed to­wards the end of the wet sea­son (peak­ing around early April). Desert warthog fe­males are polye­strous, with es­trous pe­ri­ods last­ing for about 72 hours and oc­cur­ring once every 6 weeks (if her egg was not fer­til­ized). Births occur be­tween Au­gust and De­cem­ber, with most oc­cur­ring in late Sep­tem­ber. Desert warthogs give birth to 2 to 3 off­spring per year. Young emerge from the bur­row to feed on grasses at about 3 weeks of age, though they are not fully weaned until they are about 6 months old. Off­spring fol­low the mother wher­ever she goes, suck­ling as much as every 40 min­utes, using her as shade from the hot sun, and some­times using her feces as a food source. Desert warthogs are thought to be­come sex­u­ally ma­ture slightly ear­lier than com­mon warthogs, which ma­ture at 1.5 years. (d'Huart and Grubb, 2001; De­lany and Hap­pold, 1979; Estes, 1991; King­don, 1979)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
• viviparous

• Breeding interval

  Desert warthogs breed once yearly.

• Breeding season

  Desert warthogs breed from March to May, in general.

• Range number of offspring

  1 to 8

• Average number of offspring

  2 to 3

• Range gestation period

  160 to 175 days

• Average gestation period

  170 days

• Range weaning age

  2.5 to 6 months

• Average weaning age

  3 months

• Range time to independence

  1.5 to 2 years

• Average time to independence

  2 years

• Range age at sexual or reproductive maturity (female)

  1.0 to 1.5 years

• Range age at sexual or reproductive maturity (male)

  1.0 to 1.5 years

Be­cause it takes desert warthog piglets over a year to fully ma­ture, parental in­vest­ment is sig­nif­i­cant. Males gen­er­ally con­tribute very lit­tle to par­ent­ing as they more or less leave the group after mat­ing sea­son. There­fore, fe­males must both pro­vide food for the off­spring as well as teach them how to find food and avoid pre­da­tion. Also, be­cause ju­ve­niles take so long to be­come in­de­pen­dent, fe­males may have two sets of young for a pe­riod of time, older young and newly born piglets. Birth takes place in a bur­row, where fe­males re­main for long pe­ri­ods with new­borns to nurse them for about a week. After that she will re­turn often after short feed­ing pe­ri­ods for more nurs­ing. Sev­eral months later, when off­spring are ready for sus­tained ex­cur­sions out­side of bur­rows, the mother (along with other fe­males in her group) must con­stantly be aware of preda­tors and sound the alarm when one is spot­ted. Usu­ally fe­males will de­fend their young with great vigor, though there is a re­ported case of moth­ers stand­ing idly by while a hyaena killed and ate a ju­ve­nile. (Estes, 1991; King­don, 1979)

• Parental Investment
• precocial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female
• post-independence association with parents
• extended period of juvenile learning

Lifes­pan/Longevity

Warthogs have an av­er­age lifes­pan be­tween 7 and 18 years. How­ever, no study on lifes­pan has been done specif­i­cally on desert warthogs. Among ju­ve­niles, warthog mor­tal­ity in the wild is about 50% per year, with adult mor­tal­ity drop­ping to around 15% per year. The main limit on longevity in the wild is pre­da­tion. Boars often have higher mor­tal­ity rates than fe­males due to a ten­dency to sleep out in the open (not in a bur­row), es­pe­cially dur­ing and after the mat­ing sea­son. (d'Huart and Grubb, 2001; Estes, 1991; King­don, 1979)

• Typical lifespan
  Status: wild

  7 to 18 years

• Average lifespan
  Status: wild

  10 years

Be­hav­ior

Desert warthogs cre­ate deep bur­rows or steal them from other bur­row­ing species. These bur­rows mainly pro­vide pro­tec­tion from preda­tors, es­pe­cially for the young. Warthogs may use up to 10 dif­fer­ent bur­rows when mov­ing through­out their home range, en­sur­ing that one is al­ways nearby if they are threat­ened. Desert warthogs live in so­cial groups known as "sounders." These groups are pri­mar­ily made up of fe­males and their off­spring, with males rarely drift­ing in an out when it is not the mat­ing sea­son. All mem­bers of the group, in­clud­ing adult males if pre­sent, usu­ally fol­low the old­est and largest fe­male. Often the home ranges of dif­fer­ent sounders will over­lap and the groups will at dif­fer­ent times oc­cupy the same bur­rows. A sounder that finds a bur­row al­ready taken will seek out a dif­fer­ent one. Mem­bers of dif­fer­ent groups rarely in­ter­act oth­er­wise and al­most never ex­change mem­bers. On very hot days warthogs will stay in the shade for much of the time. In cooler weather they spend much of their time graz­ing on grasses or dig­ging for roots and tu­bers. They are strongly di­ur­nal, re­treat­ing to bur­rows when it be­comes dark. How­ever, in areas where human per­se­cu­tion is more in­tense many groups have started to for­age later into the night. (d'Huart and Grubb, 2001; Estes, 1991; King­don, 1979)

• Key Behaviors
• terricolous
• diurnal
• crepuscular
• motile
• sedentary
• social
• dominance hierarchies

• Range territory size

  2 to 4 km^2

Home Range

Desert warthogs are gen­er­ally seden­tary at times, typ­i­cally stay­ing within a home range 3 to 4 km wide, but they may travel over 7 km in a day. Home ranges are often cen­tered around a wa­ter­ing hole of some kind. (d'Huart and Grubb, 2001; King­don, 1979)

Com­mu­ni­ca­tion and Per­cep­tion

Smell is the most im­por­tant and keen sense that desert warthogs have. Much of warthog com­mu­ni­ca­tion is though scent mark­ing, through tusk and pre­or­bital glands and uri­na­tion. Males use uri­na­tion to tem­porar­ily mark a bur­row as his own. Sound is also very im­por­tant, as they have a va­ri­ety of warn­ing calls used to alert the group to the pres­ence of a preda­tor. Be­cause they have com­par­a­tively weaker sight, smell and hear­ing are the main ways by which desert warthogs are alerted to dan­ger. Sight can be im­por­tant in var­i­ous so­cial dis­plays to sig­nify dom­i­nance, sub­mis­sive­ness, or an im­mi­nent at­tack. Desert warthogs have a "strut­ting" be­hav­ior, con­sist­ing of walk­ing de­lib­er­ately around a more sub­mis­sive warthog with the crest of hair and tail fully erect. Sub­mis­sive dis­plays in­clude lying flat against the ground or even rolling over to ex­pose the belly. Male warthogs fight to es­tab­lish dom­i­nance, in­clud­ing push­ing with the snout and hor­i­zon­tal strikes with tusks. (Estes, 1991; King­don, 1979)

• Communication Channels
• visual
• tactile
• acoustic
• chemical

• Other Communication Modes
• pheromones
• scent marks

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

Warthogs are her­bi­vores which feed mainly on grasses and roots. Be­cause of their harsh en­vi­ron­ments, desert warthogs are prob­a­bly less picky eaters than com­mon warthogs, which tend to feed only on se­lect plants. Warthogs eat a va­ri­ety of grasses and shrubs, and oc­ca­sion­ally fruits and some in­sects in hard times. An im­por­tant el­e­ment in their diet is un­der­ground rhi­zomes, bulbs, and tu­bers, all of which are dug up with the tusks and snout. They some­times eat their own dung and the dung of other an­i­mals. Dur­ing times of lit­tle food, they have been known to eat car­rion. Plants eaten by warthogs in­clude Sporobo­lus pel­lu­cida, Mi­crochloa kun­thii, Brachiaria, Cyn­odon dacty­lon, Chrysochloa ori­en­talis, Both­ri­ochloa, Cenchrus, Pan­icum max­i­mum, Er­a­grostis tenuifo­lia, Harpachne schim­peri, and Dig­i­taria mac­robole. They eat the fruit of Bal­an­ites, Scle­ro­carya, and Ficus species. (d'Huart and Grubb, 2001; Estes, 1991; King­don, 1979)

• Primary Diet
• herbivore
  • folivore

• Animal Foods
• carrion
• insects

• Plant Foods
• leaves
• roots and tubers
• wood, bark, or stems
• fruit
• flowers

• Other Foods
• dung

Pre­da­tion

The main preda­tors of desert warthogs are large cats, in­clud­ing lions, leop­ards, and chee­tahs. Hyae­nas have also been known to hunt warthogs. Adult and ju­ve­nile warthogs run to the near­est bur­row when threat­ened. All but the youngest in­di­vid­u­als enter the hole tail-first, en­abling them to use their tusks against the at­tack­ing preda­tor. Though they can run at 55 km/hr, warthogs do not have the speed or en­durance that many other prey an­i­mals have in sub-Sa­ha­ran Africa, and so must get to a bur­row as fast as pos­si­ble. Lions pose an es­pe­cially great threat to desert warthogs be­cause they can dig warthogs out of their bur­rows. Desert warthogs have spe­cific warn­ing grunts and sounds that cause all mem­bers of a group to be on high alert. Ju­ve­nile warthogs, upon hear­ing a spe­cific sound from the mother, will freeze in place then dash to the near­est bur­row as fast as pos­si­ble. (Estes, 1991; King­don, 1979)

• Known Predators

  • lions (Panthera leo)
  • leopards (Panthera pardus)
  • cheetahs (Acinonyx jubatus)
  • spotted hyaenas (Crocuta crocuta)

Ecosys­tem Roles

All warthogs con­sume large amounts of grass and may in­flu­ence plant com­mu­ni­ties through their for­ag­ing. Their abil­ity to take and use the bur­rows of other an­i­mals (such as aard­varks) has a neg­a­tive eco­log­i­cal im­pact on those species. Be­cause they are a host for the tick Or­nithodoros moubata, warthogs are a reser­voir for African swine fever. They also serve as a pre­ferred host for tsetse flies. (Estes, 1991; Estes, 1991; d'Huart and Grubb, 2001; Estes, 1991)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Warthogs are iconic an­i­mals of the African sa­vanna, so they can con­tribute to eco­tourism. They also can be hunted and used as a source of food. (Estes, 1991)

• Positive Impacts
• food
• ecotourism

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Warthogs can be agri­cul­tural pests, caus­ing dam­age to bean, rice, or wheat fields. Their bur­row­ing can cause prob­lems for live­stock or ma­chin­ery. In the past warthog elim­i­na­tion cam­paigns were es­tab­lished to con­trol warthogs as reser­voirs for African swine fever, which can be trans­mit­ted to do­mes­ti­cated pigs. These cam­paigns are less com­mon now as it is known that the dis­ease is trans­mit­ted by ticks and thus re­mov­ing the orig­i­nal wild host will do lit­tle to stop its spread. Rarely, and only when threat­ened, warthogs have at­tacked hu­mans. This has lead to in­jury and, in a few cases, death. (King­don, 1979)

• Negative Impacts
• crop pest
• causes or carries domestic animal disease

Con­ser­va­tion Sta­tus

Desert warthogs are not con­sid­ered threat­ened, as they have a large dis­tri­b­u­tion and are adapt­able. How­ever, pop­u­la­tions are con­sid­ered in de­cline and face con­tin­ued threats through human per­se­cu­tion in the form of hunt­ing and com­pe­ti­tion for for­ag­ing habi­tat with do­mes­tic live­stock. In areas where human per­se­cu­tion is in­tense many pop­u­la­tions have be­come some­what noc­tur­nal- a change from their nor­mal di­ur­nal lifestyle. (King­don, 1979)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  No special status

Other Com­ments

For most of the last cen­tury, African warthogs were con­sid­ered a sin­gle species, Pha­co­choerus aethiopi­cus. It was only in the last decade that desert warthogs (Pha­co­choerus aethiopi­cus) and com­mon warthogs (Pha­co­choerus africanus) were rec­og­nized as two dis­tinct species. This recog­ni­tion was based mainly on ge­netic ev­i­dence. As a re­sult there is lit­tle spe­cific re­search that has been done on the be­hav­ior, ecol­ogy, and life his­tory of desert warthogs. Nearly all avail­able in­for­ma­tion on warthogs, es­pe­cially from prior to 2001, may or may not be ap­plic­a­ble to what is now known as Pha­co­choerus aethiopi­cus. How­ever, the two species are sim­i­lar in ap­pear­ance, eco­log­i­cal im­pact, and be­hav­ior and much of the above in­for­ma­tion is based on a com­bi­na­tion of stud­ies on both species of African warthogs. In­for­ma­tion may change as fur­ther sci­en­tific re­search is com­pleted. (d'Huart and Grubb, 2001; Randi, et al., 2002)

Con­trib­u­tors

Ian Winkel­stern (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, Phil Myers (ed­i­tor, in­struc­tor), Mu­seum of Zo­ol­ogy, Uni­ver­sity of Michi­gan-Ann Arbor, Tanya Dewey (ed­i­tor), An­i­mal Di­ver­sity Web.

Ref­er­ences

De­lany, M., D. Hap­pold. 1979. Ecol­ogy of African Mam­mals. New York: Long­man Inc..

Estes, R. 1991. The Be­hav­ior Guide to African Mam­mals. Berke­ley, Los An­ge­les, and Lon­don: Uni­ver­sity of Cal­i­for­nia Press.

Honacki, J., K. Kin­man, J. Koeppl. 1982. Mam­mal Species of the World: a Tax­o­nomic and Ge­o­graphic Ref­er­ence. Lawrence, Kansas: Allen Press Inc. and The As­so­ci­a­tion of Sys­tem­at­ics Col­lec­tions.

King­don, J. 1979. East African Mam­mals. Chicago: Uni­ver­sity of Chicago Press.

Randi, E., J. D'Huart, V. Luc­chini, R. Aman. 2002. Ev­i­dence of two ge­net­i­cally di­ver­gent species of warthog, Pha­co­choerus africanus and P. aethiopi­cus (Ar­tio­dactyla: Suiformes) in East Africa. Mam­malian Bi­ol­ogy, 67/02: 92-96.

d'Huart, J., P. Grubb. 2001. Dis­tri­b­u­tion of the com­mon warthog (Pha­co­choerus africanus) and the desert warthog (Pha­co­choerus aethiopi­cus) in the Horn of Africa. African Jour­nal of Ecol­ogy, 39: 156-169.