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Pigs, Peccaries and
Hippos Status Survey and Action Plan (1993) Chapter 4.4 The Bush Pigs (Potamochoerus porcus and P. larvatus Paul Vercammen, Armin H. W. Seydack and William L.
R. Oliver. Status and Action Plan Summary Status categories 1-2 (widespread and locally
abundant or relatively secure) - both species. The bushpig, Potamochoerus
larvatus, and red river hog, P.
porcus, remain relatively widely distributed and are locally abundant in
some places, and neither is considered threatened over the majority of their
known ranges at the present time. Both species live in small family groups,
usually comprising 4-10 individuals, and are rarely observed in larger
numbers. They are usually sedentary and territorial. In most areas they are
predominately nocturnal, but tend towards diurnalism if undisturbed.
Reproduction is seasonal with litter size from one to six, but generally only
one or two young are reared successfully. Both species, but particularly
bushpigs, are notorious for their depredations on crops. There is evidence
that the conversion of former forest to secondary scrub and agriculture has
resulted in an increase in their numbers in some areas, and attempts to
control or eradicate them have usually proved unsuccessful. As neither species is considered threatened,
priority recommendations are primarily directed towards: a) the resolution of
outstanding questions pertaining to their systematic relationships and the
distinctness of some regional populations of P. larvatus; b) the need to conduct
more field studies on their ecology, behaviour, management and socio-economic
importance to local people; and c) obtain additional field status data in
areas where they remain poorly known. Introduction Following Grubb (this vol. section 4.1), two species
of 'bush pigs' are recognized: the red river hog Potamochoerus porcus (0 ssp.) and the bushpig, P. larvatus (4 + ? ssp.), though the
genetic and distributional relationships of the two species remain uncertain
in the interface between their respective known ranges. Both species are of medium body size, with an
elongated snout and a long, often brightly colored coat. The red river hog, P. porcus, is always bright rufous in
color, with a distinct white dorsal stripe and crest, long white whiskers and
eartufts. The species occurs only in Equatorial [West] Africa, from Senegal
in the extreme west, and east and south to eastern Zaire (now Democratic
Republic of Congo). Geographical variation is slight, though there is an east
(largest) to west (smallest) cline in body size in specimens from eastern
Zaire and Cameroon, respectively. However, any such geographic variation is
considered insufficient to warrant subspecific separation (P. Grubb, this
vol. and in litt.) The bushpig is light red to brown, gray or
predominately black in color, sometimes with, but often without, the distinct
white masks and long eartufts characteristic of P. porcus (for a full
description of regional variants see Grubb, this vol.). P. larvatus has a relatively wide range, extending from Somalia
in the north-east, to east and south Zaire in the west, to Natal and Cape
Provinces of South Africa in the south (Fig. 9). The four, currently
recognized subspecies are: P. l. hassama, eastern Africa; P. l. koiropotamus, Angola and south-eastern Africa; P. l. larvatus from Mayotte (Comoro Is. and
western Madagascar); and P. l. hova from eastern Madagascar. However, the Madagascan/Comoron populations are
almost certainly introduced, and there is not yet enough evidence to justify
the recognition of two possibly distinct populations in eastern
Somalia/northern Kenya (i.e. P. l.
'somaliensis' - herein considered as P.
l. hassama) and southernmost, apparently isolated population in Cape
Province (i.e. P. l. 'nyasae' -
herein considered as P. l. koiropotamus;
P. Grubb, pers. comm.). Link to Fig. 9:
Approximate former and present known distribution of the red river hog, Potamochoerus porcus, and the bushpig,
P. larvatus ssp. Former and Present Distribution P. porcus remains relatively widely, but
now patchily, distributed through much of it its former range in Equatorial
West Africa from Senegal/Gambia in the west, through the Guineo-Congolian
rain forest zone, extending northwards into the Sudanian transitional zone
(Stuart and Adams, 1990). In central and eastern Africa, it occurs at least
as far north as southern Chad and at least as far east as Virunga and Garamba
National Parks in eastern Zaire (now Democratic Republic of Congo). The
species may also occur in extreme south-western Sudan (Hillman, 1982; J. C.
Hillman, pers. comm.), though the animals reported from this country so far
are P. l. hassama (P. Grubb, pers. comm.). Further east and in south-eastern
Zaire the species is replaced by P. larvatus (see below). However, the
precise limits of the ranges (or intergradation ?) of these two species in
this region and elsewhere in southern Zaire, and hence also their ecological
and systematic relationships, has yet to be established (P. Grubb, pers.
comm. and this vol., section 4.1). P. larvatus hassama occurs in Eritrea and Tigre
Provinces of Ethiopia in the north, (presumably) extending through
south-western Sudan on both sides of the Nile. The subspecies P. l. somaliensis (if valid) replaces hassama in the vicinities of the Tana,
Juba and Scebeli Rivers in Somalia, N. E. Kenya, and perhaps as far south as
Tendaguru on the coast of north Tanzania. The identity of the bushpigs in
central Tanzania remains uncertain, so the northern limits of the range of P. l. koiropotamus are provisionally
given as southern Tanzania and south-eastern Zaire. This race has by far the
largest range of any of the currently recognized subspecies, though it should
be reassigned to 'P. l. nyasae' if
the (now ?) isolated population in the southern Cape (the origin of the
holotype) is shown to be subspecifically distinct (Grubb, this vol.). It
otherwise occurs throughout south-eastern Africa, at least as far south as
Natal Province in South Africa, as well as in a few isolated locations in
west and central Angola. As previously stated, the origins and distinctness
of the Madagascan subspecies, P. l.
hova and P. l. larvatus, is
problematic. The eastern 'race', P. l.
hova, closely resembles P. l. koiropotamus,
but is smaller in size than the mainland form and the nominate P. l. larvatus from western Madagascar
and Mayotte. Clearly, more specimens are needed to elucidate the validity of
these subspecies, which are reported to occur in all terrestrial habitats on
Madagascar, except in the environs of the major townships and the deforested
central plateau (M. Nicoll and F. Rakotondraparany, pers. comm.). Data on the former distributions of both of these
species are sketchy and imprecise. However, there has been an evident
contraction in the recent range of P. porcus, particularly in the west and
extreme north of its range. The expansion of the Sahel zone and, hence, a
reduction in cover and the availability of open water, has resulted in a
similar contraction in the range of P. larvatus in parts of N. E. Africa.
Nonetheless, both species seem to have maintained their presence over the
majority of their former ranges, and recent, localized expansion in their
ranges has been reported in some areas, e.g. in Botswana (Lloyd and Millar,
1983). Habitat, Ecology and Behavior The distribution of both species is apparently
limited by the continuous availability of food, water and cover, and they are
only rarely reported in open woodland, savannah or other more arid and open
habitats. The only field study to have been conducted to date
on P. porcus was by Oduro (1989) in
Nigeria. From this and other (mostly anecdotal) sources, it appears that this
species occurs in a wide range of habitats, including lowland rain forest,
gallery forest, dry forest, savannah woodland, and mixed scrub and cultivated
areas. From what is known, P. larvatus also occurs in an astonishingly wide range of
habitats from sea-level to montane forest (up to 4,000 m on Mt. Kilimanjaro),
to gallery forest, flooded forest and swampland, woodland, and mixed scrub
and cultivation areas. The species was the subject of a recent, intensive
study by Seydack (1983, 1990, 1991). Earlier accounts of its natural history
include those of Phillips (1926), Maberly (1967), Attwell and Bearder (1976)
and Breytenbach (1979). General accounts of the species' biology are also
provided by Sowls and Phelps (1968), Skinner et al. (1976), Ghiglieri et al. (1982) and Kingdon (1982). Both species are predominately nocturnal, though a
clear seasonal trend amongst bushpigs in the southern Cape towards more
diurnal activity during winter suggests that temperature regulation, rather
than hunting pressure, may be the underlying factor in the daily activity
patterns of this species. During periods of inactivity they shelter in dense
vegetation, and they may construct bad weather nests during cold and wet
spells. Average daily movement distances for bushpigs were found to be 3 km,
ranging between 0.5 and 5.8 km (Seydack, 1990). They are omnivorous, and may be potentially
important dispersers of seeds. The diet of Cape bushpigs was found to
comprise 40% subterranean plant parts (mostly tubers, rhizomes and corms),
30% herbage, 13% fruit, 9% animal matter and 8% fungi (Seydack, 1990). Field
studies of this species in Uganda have revealed that bushpigs often associate
with groups of foraging monkeys in order to feed on discarded fruits
(Ghiglieri et al., 1982). They are
also opportunistic predators, and consume a range of invertebrates, smaller
vertebrates and carrion. Most reports indicate that both species typically
live in family groups of 9 -15 individuals, though P. larvatus group sizes in South Africa were found to range from
1 to 10, with average of 2.4 individuals (Seydack, 1990). Similarly, in
Madagascar groups seldom comprise more than 5 individuals (M. Nicoll, pers.
comm.). Contrarily, Oduro (1989) recorded P.
porcus groups of 1 - 15 (x = 10.56) with an immature/adult age ratio of
2:1 in Nigeria, and much larger groups of 30-60 red river hogs have been
observed on occasions in Guinea and E. Zaire (L. Macky and J. Hart, pers.
comm.). Population density estimates in the southern Cape
ranged from 0.3 to 0.5 bushpigs per sq. km, and average home range sizes in
the Knysna Forest ranged between 3.8 and 10.1 sq. km (n = 8), with an average
of 7.2 sq. km (Seydack, 1990, 1991). The home ranges of the pair-bonded
adults in this study area were spatially exclusive, i.e. resource
territoriality was actively maintained through defense and patrolling. This
study also confirmed the earlier anecdotal accounts of Maberly (1967),
Attwell and Bearder (1976) and Skinner et al. (1976) of a monogamous mating
system in which adult boars play an active role in the rearing and defense of
the young. Reproduction in both species is apparently seasonal,
with piglets being most frequently reported towards the end of the dry season
or coinciding with the onset of the rainy season. Nearly 75% of births in the
bushpig population in Cape Province studied by Seydack (1990) occurred during
the spring (September to November), which agrees with earlier records
suggesting farrowing taking place during the spring and summer (Sowls and
Phelps, 1968; Tinley, 1977). Available data indicate that both species have a
similar gestation period of c. 120 days, and litter size of 1-6, with a mode
of 3 (Oduro, 1989; Neurohr, 1991; Seydack, 1991). Mortality due to starvation has been recorded in all
age classes of P. larvatus in the
southern Cape. However, inclement weather and predation were predominant
mortality factors for immature animals according to Seydack's (1990, 1991)
findings, whereas intraspecific strife played a significant role in adult
mortality. Threats to Survival Although habitat destruction is not considered a
major threat to the survival of either of these species over most of their
ranges at the present time, deforestation coupled with intense hunting
pressure has inevitably resulted in marked range contractions in some
countries/regions. In Benin, (north) Equatorial Guinea and (possibly) south
Sierra Leone, for example, P. porcus is reported to be rare or absent outside
existing protected areas (A. Green, pers. comm.; A. Blom, pers. comm.; G.
Teleki, pers. comm.), though precise data are difficult to obtain owing to
the species' secretive and nocturnal behaviour. Similarly, P. larvatus is reported to be scarce
or absent outside the better protected areas in Burundi (P. Chardonnet, pers.
comm.), though it is doubtful if this species is as seriously threatened as
many of the other larger mammals in this country. Indeed, both species are apparently highly adaptable
and may even benefit by the opening up of former forested areas by the
creation of secondary habitats, the provision of cultivated foodstuffs and
reductions in the numbers of their natural predators. Both bushpigs and river
hogs are notorious for their depredations on crops. In Zaire (now Democratic
Republic of Congo) and Malawi, for example, bushpigs are reputed to cause
more damage to agriculture, particularly maize crops, than any other species
(R. Bell, pers. comm.). For these reasons, and because they are sometimes
regarded as important vectors of livestock diseases (see below), they are
widely persecuted by farmers and they are frequently targeted in wildlife
control programmes. Generally speaking, all such eradication attempts have
been unsuccessful, largely because of the species' cryptic lifestyle and
relatively high reproductive potential. Both species are also hunted widely for subsistence
purposes, though they undoubtedly benefit from taboos on the consumption of
pork in many parts of their ranges. Amongst some Zambian tribes, for example,
bush pig meat is considered to be unhealthy, even dangerous, because the
animals are reputed to harbor various diseases, including epilepsy. These
beliefs may have been influenced by the spread of Islam, which effectively
affords these animals a good deal of protection against hunting in many
African countries and in some parts of Madagascar. However, even in
predominantly Muslim countries, it is doubtful if they are completely free of
hunting pressure, since some Muslim groups discriminate between the 'red'
meat of Potamochoerus (which is eaten) and the 'white' meat of other suids
(P. Chardonnet, pers. comm.), whilst many others permit hunting by non-Muslim
groups (e.g. in Sierra Leone; G. Davies, pers. comm.) or even hunt wild pigs
themselves in order to sell the meat (e.g. in Guin‚a Bissau, P. Chardonnet,
pers. comm.). Seventy-eight percent of hunters interviewed in Gabon by Lahm
(1990) cited the sale of red river hog meat as amongst their most important
sources of revenue, and that only about one-third of their gained bush-meat
was retained for domestic consumption. In Gabon (M. Nicoll, pers. comm.),
Zaire (K. H. Smith, pers. comm.) and Guin‚a Bissau (P. Chardonnet, pers.
comm.) most animals killed by hunters and farmers are used for local
consumption, though there is some local trade to village or city markets.
With the exception of a few live individuals exported to zoos (see later
text), there is no international trade in these species, or their meat, hide
or other products, as far as is known. Potamochoerus spp. are allegedly host to or
vectors of tick-borne diseases, such as trichinosis, African swine fever and
probably trypanosomes (W. Odura and F. Amubode, pers. comm.). However, the
significance of this has yet to be verified. Dorst and Dandelot (1970), Lever (1985) and Oliver
and Brisbin (this vol.) cite records of the occurrence of feral pigs (Sus
scrofa) in several parts of Sudan and in South Africa. Some of these animals
became naturalized as early as 1925, either as a consequence of allowing
domestic stock to range freely or by their deliberate introduction in an
effort to control the pine tree emperor moth (Nudaurelia cytheria), whose pupae are readily consumed by these
animals (Thomas & Kolbe, 1942). Hybridization between P. larvatus and S. scrofa was recorded in the Transvaal in the early 1970's, when
an (escaped) domestic sow was mated by a male bushpig and the resulting
progeny (a litter of eight) were reported to have bushpig characteristics
(Smithers, 1983). Simoons (1953) also cited references to the interbreeding
of Potamochoerus with domestic pigs
in the Congo and in the Niger Delta. More recently, Eurasian wild pigs (S. scrofa), introduced for hunting
purposes, have become established in a more or less free-ranging state in
Burkina Faso, Gabon and, probably, Zaire. In the Wonga-Wongue Presidential
Hunting Reserve in Gabon, these animals are reported to have interbred with P. porcus, and that their hybrid
offspring are running wild (East, 1990). Whilst it is important to stress
that evidence for such intergeneric hybridization remains anecdotal and that
putative hybrids have yet to be critically examined and described,
introductions of S. scrofa
apparently pose a threat to the genetic integrity of local Potamochoerus
populations, as well as a risk of disease transmission. Conservation Measures Taken Both species are known or are likely to occur in all
of the principal protected areas within their respective ranges. In all
countries with an existing protected areas network, hunting is forbidden or
is restricted to permit holders. In most countries such permits are usually
given only for scientific research purposes, although they have also been
issued on occasions (e.g. in Malawi; R. Bell, pers. comm.) to reduce the
numbers of these animals following repeated complaints from local farmers
about their damage to crops in neighboring areas. Outside designated national parks and wildlife
reserves, protective legislations are more varied. In Guinea, Liberia and
Sierra Leone, for example, Potamochoerus
spp. remain unprotected and can be legally hunted at all times, whereas in
most other countries they are treated as game animals which can only be
hunted during an open season. In only a very few countries, such as Burundi,
where they are now confined to a few isolated locations, are they protected
at all times and throughout their remaining range. In theory, in those areas
where hunting is controlled the number of animals taken by one hunter is
limited and/or confined to particular age/sex classes. In Gabon, for
instance, hunting permits are issued for no more than 2 adult P. porcus,
whilst in Nigeria sows with piglets or immature animals are protected at all
times. However, in many African countries, particularly in
west and central Africa, law-enforcement is problematic, and in several
countries it is virtually non-existent. In Benin, Central African Republic,
Gabon, Ghana, Nigeria, Sierra Leone, Liberia, Sudan and Zaire (now Democratic
Republic of Congo), for example, poaching is rife even within many nominally
protected areas. By comparison, wildlife protection laws in some other
countries, such as Zimbabwe, Botswana, Namibia and South Africa, are
sufficiently well enough enforced to largely preclude the poaching of these
animals within protected areas, though farmers may still be permitted to
exercise control of their numbers elsewhere. Captive Breeding Both species are extremely rare in captivity outside
their countries of origin, though specimens have been exhibited at intervals
in various collections in Europe and the U.S.A. since the middle of the 19th
century. However, they have been bred only very occasionally, and never in
sufficient numbers to be self-sustaining, let alone meet the undoubted demand
for exhibition purposes. Longevity was also very poor amongst the early
captives, though a female red river hog was maintained at the Frankfurt Zoo
from 1959 to 1979, whilst another female of the same species currently held
in the Duisburg Zoo is close to breaking this 20 year record (Gewalt, 1988). A small group of red river hogs has been maintained
and bred in the Duisburg Zoo since 1979, though these animals are all
descended from a single wild-caught pair from Togo. These animals, and
another wild-caught pair from Togo recently imported by the Los Angeles Zoo,
are thought to be the only specimens of this species held anywhere outside
Africa at the present time. Moreover, the prospects for any further exports
are diminishing with the imposition of increasingly stringent veterinary
regulations concerning the movement of wild pigs throughout the European
Community and in North America. Additional Remarks These species are maintained in a number of
collections in Africa. However, few if any efforts have been made to develop
properly structured research or captive breeding programmes within their
countries of origin, or to explore their evident commercial potential for
pork production. Although there is no evidence that Potamochoerus has ever been truly domesticated, Simoons (1953)
has cited references to the semi-domestication or at least taming of P. porcus by various peoples along the
northern border of the rainforest zone, as well as early accounts which
suggest the species was taken to South America, where it was encountered in
feral and tamed states, and to England, where it was alleged to have been
used for cross-breeding with domestic pigs, S. scrofa (see earlier text). The (presumed) introduction of P. larvatus to Madagascar and the
Comoro Is. might also reflect an earlier, and hitherto largely unsuspected,
cultural and economic importance attached to these animals amongst some
ethnic groups, which undoubtedly merits further investigation. In the Iyiocha
Forest Reserve in southern Nigeria, for example, local tribal groups accord P. porcus the status of "king of
the forest" (W. Oduro, pers. comm.). If an animal is killed, its carcass
is carried to the traditional chieftain's palace before it is allowed to be
butchered, and the meat is shared among the members of the chief's clan, and
only a portion is given to the hunter. Conservation Measures Proposed: An Action Plan Given that both species remain widely distributed,
are well represented in numerous national parks and reserves, and are
maintaining their numbers outside these areas in many parts of their ranges,
neither species should be regarded as threatened at the present time. Indeed,
in some areas there may even be a need to instigate more rigorous population
control measures, as in some parts of Madagascar where (introduced?) bushpigs
are reported to pose a serious threat to some native wildlife species.
However, whilst species' conservation per se is not an issue at present,
these species are threatened in some countries/regions, and efforts should be
made to conserve these populations. In addition, very few field studies have
been conducted to date, and many basic aspects of their systematics, biology
and management requirements are poorly known and merit further investigation.
Objectives: 1. To obtain a better understanding of the distribution, genetic
variation and systematic relationships of these species. 2. To obtain
distribution and population status data in those areas where this information
is lacking at present. 3. To encourage
further studies of the population biology, ecology and behaviour of these
species, and their socio-economic importance to tribal societies. 4. To promote
the development of management programmes designed to: a) protect remnant
populations in countries/regions where either species are threatened, or b)
ensure the sustainable harvesting of these animals in areas where they remain
abundant as an important resource for local people. Priority Projects: 1. Obtain
additional cranial, skin and cytogenetic specimen material (and photographs)
from particular key locations, with a view to the resolution of outstanding
systematic questions. Various questions pertaining to
the geographic and genetic variation in these species, and their systematic
relationships, remain unresolved at present owing to the absence or shortage
of comparative specimens from particular key locations. These locations and
questions include: a) Madagascar: further research is needed to check the
validity of the subspecies hova and
larvatus, and the relationships
(and possible origins) between these animals and those of the African
mainland; b) east and south Zaire and neighboring countries: obtain
comparative specimens in the contact zone between P. porcus and P. larvatus,
investigate reports of polymorphism in some of these populations, and
reassess the distribution and taxonomic status of these animals in the light
of these results; and c) Somalia and north-east Kenya: obtain additional,
comparative taxonomic materials to assess the validity of separating 'P. l. somaliensis' from P. l. hassama, and obtain more details
about the distribution and status of bushpigs in this region. (Also see
Grubb, this vol.). 2. Promote field studies on the biology and ecology
of P. larvatus and, particularly P. porcus. Very few field studies have been
conducted on either of these species and, as far as is known only one such
study (in southern Nigeria by Oduro, 1989) has been undertaken on P. porcus. Further, comparative
studies are required in order to obtain a proper understanding of their
natural history and possible future management needs. 3. Collect population distribution and status data
in selected areas. At present, available data are
inadequate or entirely lacking from a number of regions/countries, including
Sudan, northern Ethiopia, south-east Somalia, central Zaire, Togo, Angola and
Mozambique. In some of these areas, however, continued political unrest may
preclude data collection in the near future, and may be a cause for concern
in respect of its implications for increased hunting pressure to provide bush
meat to military and displaced persons, and the ineffective protection of
designated parks and reserves. 4. Investigate
occurrence and status of introduced and feral pig populations, encourage
their control or eradication, and discourage any future introduction
attempts. Updated data are required on the
distribution and status of all naturalized pig populations, and the threats
these pose to the genetic integrity and health of native wild pigs and other
species. In particular, recent reports of P.
porcus X S. scrofa hybrids in Gabon and elsewhere should be investigated,
and voucher specimens of presumed hybrids (skeletons, skins, blood and cell
samples) should be obtained because of their scientific interest.
Nonetheless, support should also be given to the control or removal of these
animals, just as similar support should be given to the control of any
introduced populations of P. larvatus
in those locations in Madagascar or the Comoro Islands where they are known
or presumed to pose a primary threat to native wildlife species. (Also see
Oliver and Brisbin). 5. Encourage
anthropological (including archaeozoological) research on the socio-economic
significance of Potamochoerus and other native wild pigs amongst ethnic
groups, and promote studies designed to investigate the possible future use
of these animals for domestic husbandry. (Also see Oliver et al. this vol., Chapter 4.9). Acknowledgements Grateful thanks are extended to the following
correspondents who completed the African Suiform Survey report forms and
supplied numerous reprints and other data: F. O. Amubode, W. F. N. Ansell, J.
J. Ballestra, R. H. V. Bell, A. Blom, J. C. Bolibar, T. Butynski, A. Camara,
P. Chardonnet, B. Child, G. Davies, A. Dupuy, F. Fagotto, J. M. Fay, J. M.
Fryxell, M. E. J. Gore, J. M. Grandvergne, A. A. Green, R. Harding, J. Hart,
J. C. Hillman, K. Hillman-Smith, N. Innocent, R. C. V. Jeffery, A. Laurent,
L. Macky, H. Mertens, J. Maronga-Mbina, N. Monfort, F. E. C. Munyenyembe, J.
Newby, M. Nicoll, B. Y. Ofori-Frimpong, A. Peal, F. Rakotondraparany, P. J.
J. van Rensburg, C. A. Spinage, M. Storz, G. Teleki, J. P. Thomassey, P.
Trenchard, J. Verschuren, S. Vrahimis, P. L. Walker and V. Wilson. Peter
Grubb and Kristin Leus provided numerous valuable comments and suggestions on
earlier drafts of this manuscript, and Peter Cuypers was largely responsible
for the preparation of the distribution map. References Ansell, W. R.
H. 1978. Mammals of Zambia. National Parks and Wildlife Service, Chilanga,
Zambia: pp. 51-52. Attwell, C. A.
M. and Bearder, S. 1976. The bushpigs of Narina. Afr. Wildl. 30(2): 12-13. Breytenbach, G.
J. 1979. The enigmatic bushpig. African Wildl. 33 (5): 48-49. Davies, A. G.
1987. The Gola Forest Reserves, Sierra Leone. Wildlife Conservation and
Forest Management. I.U.C.N., Gland. Dorst, J. &
Dandelot, P. 1970. A Field Guide to the Larger Mammals of Africa, Collins,
London: 173-179. du Plessis, S.
F. 1969. The past and present distribution of the Perissodactyla and
Artiodactyla in Southern Africa. (Unpubl.) M.Sc. thesis, Univ. of Pretoria. East, R. 1990.
Antelopes - Global Survey and Regional Action Plans, Part 3. West and Central
Africa. IUCN, Gland, Switzerland: 171 pp. Fagotto, F.
1985. Larger animals of Somalia in 1984. Environ. Conserv.12 (3): 260-264. Gartland, S.
1988. Conservation et Utilisation Rationelle des Ecosystemes Forestieres en
Afrique Centrale. Rapport National Cameroun. I.U.C.N., Gland: 179 pp. Gewalt, W.
1988. Uber einige seltene Nachzuchten im Zoo Duisburg. 5. Pinselohrschwein (Potamochoerus porcus). Zoologischer
Garten 58: 79-114. Ghiglieri, J.
P., Butynski, T. M., Struhsaker, T. T., Leland, L., Wallis, S. J. and Waser,
P. 1982. Bush pig, Potamochoerus porcus,
polychromatism and ecology in Kibale Forest, Uganda. Afr. J. Ecol. 20:
231-236. Haltenorth, T.
and Diller, H. 1977. A Field Guide to the Mammals of Africa. Collins, London:
29-32. Hillman, J. C.
1982. Wildlife information Booklet. Dep. of Wildlife Management, Sudan: pp.
33-38. Howard, P. C.
and Marchant, A. N. 1984. The distribution and status of some large mammals
on private land in Natal. Lammergeyer, J. Natal Parks Board, 34: 1-11. Hulberg, R. B.
and Carrol, R. W. 1982. Wildlife research in Manova-Gounda-Saint Floris
National Park, Central African Republic. U.S. Peace Corps rep. I.U.C.N. 1987.
The IUCN Directory of Afrotropical Protected Areas. I.U.C.N., Gland. 1034 pp. Kingdon, J.
1982. East African Mammals, Vol. IIIB. Academic Press, London: 200-209. Lahm, S. 1990.
Impact of human activity on antelope populations in Gabon. Gnusletter 10 (1):
7-8 Lever, C. 1985.
The Naturalised Mammals of the World. Longman, London and New York: p. 115. Limoges, B. (in
press.). Wildlife census in Guinea Bissau. Lloyd, P. H.
and Millar, J. C. G. 1983. A questionnaire survey (1969-1974) of some larger
mammals of the Cape Province. Bontebok 3: 1-149. Maberly, C. T.
A. 1967. African bushpigs. Animals 9(10): 556-561. Neurohr, B.
1991. Zucht- und Haltungserfahrungen beim Pinselohrschwein (Potamochoerus porcus) im Zoo Duisberg.
Bongo, Berlin 18: 254-257. Oduro, W. 1989.
Ecology of the red river hog in southern Nigeria. (Unpubl.) Ph.D. thesis,
Univ. of Ibadan, Nigeria. Phillips, J. F.
V. 1926. "Wild pig" (Potamochoerus
choeropotamus) at the Knysna: notes by a naturalist. S. Afr. J. Sc. 23:
655-660. Rautenbach, I.
L. 1982. Mammals of the Transvaal. Ecoplan Monograph No. 1, Pretoria, South
Africa: pp. 163-165. Roure, G. 1968.
Animaux Sauvages de Haute-Volta et des Pays Voisens. (Unpubl.) rep.,
Direction des Eaux et Forests, Ministere de 'l'agriculture, Ouagadougou,
Upper Volta: 64 pp. Sayer, J. A.
and Green, A. A. 1984. The distribution and status of large mammals in Benin.
Mammal Rev. 14 (1): 37-50. Seydack, A. H.
W. 1983. Age assessment of the bushpig (Potamochoerus
porcus Linn. 1758) in the Southern Cape. (Unpubl.) M.Sc. thesis, Univ. of
Stellenbosch: 196 pp. Seydack, A. W.
H. 1990. Ecology of the bushpig (Potamochoerus
porcus Linn. 1758) in the Cape Province, South Africa. (Unpubl.) Ph.D.
thesis, Univ. of Stellenbosch: 728 pp. Seydack, A. H.
W. 1991. Monographie des Buschschweines (Potamochoerus
porcus). Bongo, Berlin 18: 85-102. Simoons, F. J.
1953. Notes on the bush-pig (Potamochoerus).Uganda
J. 17: 80-81. Skinner, J. D.,
Breytenbach, G. J. and Maberly, C. T. A. 1976. Observations on the ecology
and biology of the bushpig Potamochoerus
porcus Linn. in the Northern Transvaal. S. Afr. J. Wildl. Res. 6(2):
123-128. Smithers, R. H.
N. 1983. The Mammals of the Southern African Subregion. University of
Pretoria Press, Pretoria: pp. 591-598. Smithers, R. H.
N. and Wilson, V. J. 1979. Check List and Atlas of the Mammals of Zimbabwe
Rhodesia. Museum Memoir Series No. 9, Salisbury, Zimbabwe: pp. 113-116. Sowls, L. K.
and Phelps, R. J. 1968. Observations on the African bushpig, Potamochoerus porcus Linn. in
Rhodesia. Zoologica 53 (3): 75-84. Stuart, S. N.
and Adams, R. J. 1990. Biodiversity in Sub-saharan Africa and its Islands.
IUCN/SSC Occasional Papers, No.6. IUCN, Gland: 242 pp. Stuart, C. and
Stuart T. 1988. Field Guide to the Mammals of Southern Africa. London, New
Holland: p. 272. Thomas, A. D.
and Kolbe, F. F. 1942. The wild pigs of South Africa: their distribution and
habits, and their significance as agricultural pests and carriers of disease.
J. South African Veterinary Medical Assoc.13: 1-11. Tinley, K. L.
1977. Framework of the Gorongosa ecosystem. (Unpubl.) Ph.D. thesis,
University of Pretoria. Walker, P. L.
1986. Bushpig distribution and control in Natal. Lammergeyer 36: 40-45. Yalden, D. W.,
Largen, M. J. and Kock, D. 1984. Catalogue of the mammals of Ethiopia.
Monitore Zoologico Italiano, 4: 67-221. |
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