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Chapter 11: Forest hog Hylochoerus meinertzhageni (Thomas 1904)Gilbertiodendron stands (Hart 2001). In Odzala NP, northern
Republic of Congo, forest hogs spend 44 per cent of their time
feeding on herbaceous plants from hydromorphic areas, some
of these plants – Enhydra fluctuans, Paspalum conjugatum,
Ludwigia stolonifera, and Ryhynchospora corymbosa – were
significantly rich in calcium and nitrogen, which was con-
cluded to be the main reason why forest hog visit the clearings
(F. Magliocca, personal observation in d’Huart & Kingdon 2013).
However, in Dzanga-Sangha Special Reserve, Central
African Republic, hogs are attracted to forest clearings for
several reasons, the most important being their consumption
of seeds and larva found in elephant dung (Turkalo in prepa-
ration). Because the densities of elephants are higher in forest
clearings where they come in search of minerals and monocoty-
ledons, there is an abundance of elephant dung not found in the
neighbouring forest. Forest hogs have been observed rooting
through the elephant dung along the edges of the clearing, eat-
ing seeds as well as larvae found in the dung (A. Turkalo, per-
sonal observation). Occasionally, forest hogs are known to eat
meat or carrion, eggs, worms or larvae (d’Huart 1978; Kingdon
1979). In Dzanga bai they have been observed scavenging on
elephant carcasses resulting from poaching or natural death in
the clearing. Local BaAka say that they scavenge on any carcass
found in the forest (A. Turkalo, personal observation).
Reproduction and Growth
Reproduction in forest hog occurs generally between the alpha
male and the females of his own group, but copulations between
females and peripheral males also occur (d’Huart 1978). Males
can last up to seven years as dominant in a group (Klingel &
Klingel 2004). When there is a change of dominant male,
infanticide is common, with almost 100 per cent of newborns
killed by the newcomer (Klingel et al. 2001; Siege 2011; d’Huart
& Siege 2012). Mating may take place all year round (Reyna-
Hurtado et al. 2014), with a peak in February–March and
August–September in Virunga NP, DR Congo (d’Huart 1978).
Litters of up to six piglets are born after 18–21.5 weeks of
gestation, but due to infant mortality smaller litters are seen in
the field, with an average of 2.5 for Virunga NP (d’Huart 1978)
and less than four for sites in Uganda (Kingdon 1979). Adult
body size and sexual maturity are reached at 18 months. d’Huart
(1978) observed that 46 per cent of adult female produce young
every year and estimated that 113.6 young are produced in a
population of 100 adult females each year. However, field obser-
vations report that females may be careless mothers that some-
times step up or kick or push their piglets, which contributes
to infant mortality (Schneider & Viehl 2000). Based on group
composition, the sex ratio is reported as fluctuating between 1:1
and 1:2 in Virunga NP, DR Congo. The average lifespan is five
years with a maximum of 18 years (d’Huart 1978).Behaviour
The forest hog is a social species that lives in family groups con-
sisting of three to four adult females, their piglets and juveniles,
a dominant male, and occasional subordinate males. In Queen
Elizabeth NP, groups range from two to 19 (up to 24) individuals
with an average of 11.2 (Klingel & Klingel 2004). In Virunga NP, DR
Congo, the average group size was 13.9 (d’Huart 1978) and groups
in the Aberdare NP, Kenya, averaged 6.6 and ranged from two to
18 individuals (Kingdon 1979). In the dense bushes surrounded by
mature forest of Kibale NP, Uganda, the maximum group size was
11 members (Reyna-Hurtado et al. 2014). The group size of forestFigure 11.5 Female forest hog
(Hylochoerus meinertzhageni) swimming
across the Talek River, Mara National
Reserve, Kenya, 23 December 2015
(photo by Mandy Bell). (A black and white
version of this figure will appear in some
formats. For the colour version, please refer
to the plate section.).01312:33:38