Chapter 9: Common warthog Phacochoerus africanus (Gmelin, 1788)91
Feeding Ecology
Phacochoerus africanus is a medium-sized graminivore that
exhibits considerable dietary selectivity and flexibility while
depending on high-quality food. Lacking a rumen, fermenta-
tion occurs in the hindgut. Probably the most efficient among
suids and peccaries (Family Tayassuidae) in the digestion of
fibre (Clauss et al. 2008). A ‘hypergrazer’, predominantly eat-
ing short, green, grass leaves, stems, seeds, and rhizomes, but
eats a wide range of other vegetable matter, including fruits,
fungi, bark, sedges, forbs, and shrubs. Very small amounts of
animal matter eaten, including carrion, eggs, small mammals,
reptiles, birds, and invertebrates. Soil, bone, and faeces are also
eaten in small amounts (Shortridge 1934; Lamprey 1963; Field
1970; Cumming 1975; Mason 1982; Radke 1991; Skinner &
Chimimba 2005; Treydte et al. 2006; Meijaard et al. 2011).
A selective feeder, P. a f r i c a n u s pushes away unwanted items
with the head to reach preferred foods. Lips ‘pluck’ short, tufted
grass. The mouth ‘crops’ tall, coarse grass, and ‘combs-off ’ grass
flower and seed heads from the stem. The sharp, hard edge of the
rhinarium (not tusks) removes soil to 5–15 cm deep to ‘root’ rhi-
zomes. Often feeds while moving forward on fore-carpal joints
(= ‘knees’) with hindquarters raised (Cumming 1975; Skinner &
Chimimba 2005; Meijaard et al. 2011).
In north-west Zimbabwe, P. a f r i c a n u s subsist mainly on
green grass leaves during the wet season (about November–
December), mainly on green grass seeds near the end of the
wet season (about February–March), and mainly on succu-
lent rhizomes during the dry season (about June–September).
Here there is but one wet season and the dry season spans
7–8 months (Cumming 1975). There is a similar annual sea-
sonal change in diet in south-east Tanzania, where there is
also just one wet season (Rodgers 1984). Dietary change also
occurs where there are two annual wet seasons (e.g. south-west
Uganda; Field 1970, 1972). The timing of major seasonal change
in diet varies depending on when the rains begin and end (Field
1970; Cumming 1975; Mason 1982). One study in north-east
Tanzania, however, where there are two annual wet seasons, did
not find dietary switching throughout the year. Here the main
food at all times is grass leaves (Treydte et al. 2006).
At all study sites, grass parts are by far the most frequently
eaten foods (see table 3 at http://www.wildsolutions.nl/phacochoe-
rus/), with large number of species grazed (>30 species at some
sites; Cumming 1975; Treydte et al. 2006). Species in genera
Cynodon, Sporobolus, Urochloa, Eragrostis, and Echinochloa are
particularly important food for P. a f r i c a n u s (Table 9.2).
They typically drink once a day, but may drink 3–5 times a
day when the weather is hot and water is near (Cumming 1975;
Hayward & Hayward 2012). They can survive without drinking
for several months at a time (e.g. much of Botswana and north
Kenya; Smithers 1971; Somers et al. 1994; De Jong & Butynski
2014). The absence of permanent water is a serious constraint
for P. a f r i c a n u s, keeping densities low and distributions con-
fined to sites where water is seasonally available and, probably,
where moist foods are always available. In north Kenya, doum
palm Hyphaene thebaica appears to be a keystone species, fallen
fruits (often abundant) yielding food and water, and trees pro-
viding shade and cover (De Jong & Butynski 2012, 2014).Reproduction and Growth
Phacochoerus africanus males mate with more than one female
and females mate with more than one male. Both sexes reach
sexual maturity at about 17–20 months and near full physical
maturity at about 4 years. The first litter is usually produced
at about 2 years. Although males may mate at 18 months,
older males mate the most (Bigourdan 1948; Roth 1965;
Cumming 1975; Boshe 1981; Mason 1982, 1986; Somers &
Penzhorn 1992).
Monoestrous. Oestrous last up to 72 h (Clough 1969).
The dominant male inspects the area around burrows in the
morning during mating season to track down an oestrous
female and occasionally occupies the burrow with the oestrous
female that night (Cumming 1975). Secretion from the vulvaFigure 9.3 Sounder of two adult
female and six juvenile common
warthogs Phacochoerus africanus feed-
ing on the fallen fruits of doum palm
Hyphaene thebaica at 22:31 h on a clear,
moonlit night south of Sibiloi National
Park, central north Kenya. Camera trap
photo by Tom Butynski and Yvonne
de Jong..01112:33:32