|
Pigs, Peccaries and
Hippos Status Survey and Action Plan (1993) Chapter 4.2 The Warthogs (Phacochoerus africanus and P. aethiopicus) Paul Vercammen and Darryl R. Mason Status and Action Plan Summary Status categories: P. africanus is 1-2 (widespread and locally abundant or
relatively secure), except for P. a.
aeliani which is 'indeterminate'; P.
aethiopicus is 4 (vulnerable) and 'extinct' depending on ssp. With the exception of mature males, all warthogs
live in small family units. They are largely diurnal and spend the night in
burrows. They are predominantly grazers, but will eat a wide range of
vegetable matter, including some agricultural crops. If enough food and water
are available they can live their whole life in the same area, usually sharing
their home range with other warthogs, though population density may be
influenced by the availability of suitable burrows. Males will fight for
females but are not known to defend a territory. Reproduction is seasonal,
except on the equator, and litters normally range from two to five piglets. Both currently proposed species are declining over
the northern limits of their range, although the overall range of the common
warthog, P. africanus, is expanding in some other areas in response to the
opening up of former woodland. Hopes that the 'extinct' Cape form, P. a. aethiopicus, may survive in the
far northern Cape Province have proved groundless as the warthogs in this
area have functional incisors. However, the recent realization that the
Somali warthogs, P. a. delamerei,
are closely allied to the Cape form, and are ecologically adapted to an arid
environment, make these animals a high priority for conservation attention,
particularly as they not known to occur in any protected area over their
limited range. However, given the current political situation in the
Somali/Eritrea region, effective in-situ conservation measures for these
animals, and for the Eritrean warthog, P.
africanus aeliani (the most threatened subspecies of the 'common'
warthog), are likely to be difficult, so captive-breeding of both forms is
recommended as a priority and safeguard. Nonetheless, field status surveys of
the distribution and abundance of warthogs, and/or comparative studies of
their behavioral ecology, are required in these areas as soon as
circumstances permit, as well as in certain other areas where the available
data are insufficient to assess regional conservation and management problems
and priorities at the present time. Introduction Warthogs are separated into their own subfamily,
Phacochoerinae, and are amongst the most distinct and highly specialized of
all suids. Following Grubb (this vol., Section 4.1) two living species, the
common warthog, P. africanus (with
c. 4 ssp), and the desert warthog, P.
aethiopicus (with one living and one extinct ssp.) are distinguished. The
latter species is differentiated from the more familiar, common form by
various cranial and dental characters, including the absence of functional
incisors, and by its smaller body size, though its external appearance,
behavior and ecology remain poorly known. In comparison with other suids,
warthogs appear less deep in the chest, with barrel-shaped bodies, which are
sparsely haired, except for a distinct mane of long stiff hairs on the neck and
shoulders. The face is flattened and bears one or two pairs of warts and, in
both sexes, well developed tusks. The two species and their respective
subspecies may be described as follows: The Cape and Somali (or Desert) Warthog (P. aethiopicus) A live warthog sent to Holland from the Cape Colony
by Governor Tulbagh in 1765 was the first such animal to be described
(Sclater, 1900). Although warthogs became largely extinct in the Cape,
probably soon after the massive rinderpest epizootic at the end of the
nineteenth century, specimens collected from this region had no functional
incisors and were characterized by a number of other distinctive dental and
cranial features (Grubb, this vol., Section 4.1). In his review of the
taxonomy of the African suids, the latter author suggests that the warthogs
of Somalia are virtually indistinguishable from the extinct Cape form and
advocates that the Somali population should be recognized as an isolated form
of this species, both on the basis of its dental and skull characteristics
and reported sympatry with P. africanus
in northern Somalia. Accordingly, he advocates that the widely separated
southern (or Cape) and northern (or Somali) warthog variants are referred to
as P. a. aethiopicus and P. a. delamerei respectively. The
external appearance, behavior and ecology of the Somali animals are almost
unknown, though Fagotto (1985) reported that warthogs were the most
widespread and abundant large mammals, and that groups (of up to 10-15
individuals) were still present throughout most of Somalia, even in very dry
bushlands. The Common Warthog (Phacochoerus
africanus) Warthogs with functional incisors, first described
by Buffon in 1766 but not given a scientific name until 1788, proved to be
much more widely distributed, occurring in almost all sub-Saharan countries,
as far south as Natal Province (see Fig. 7). At least eight subspecies have
been described, though Grubb (this vol.) suggests that the majority of these
are synonymous and that only four subspecies should be (provisionally)
recognized at the present time, viz: ·
P. a. africanus - Sahel to central Ethiopia (now
probably extinct in Mali and Niger) ·
P. a. aeliani - northern Ethiopia and Djibouti ·
P. a. massaicus - eastern and central Africa ·
P.a. sundevallii - northern part of the southern
African sub-region. Link to Fig. 7:
Approximate former and present known distribution of the desert warthog (Phacochoerus aethiopicus ssp.) and the
common warthog (P. africanus ssp.).
Former and Present Distribution Warthogs inhabit open and wooded savannas,
grass-steppe and semi-deserts from Mauritania and Ethiopia in the north to
Namibia and Natal in the south. The two species have allopatric ranges, as
follows: Phacochoerus
aethiopicus has a
discontinuous range between north-east and extreme south Africa, though it is
evidently extinct in the latter region where it formerly occurred in the Cape
Province and apparently in Orange Free State. The species is otherwise
confined to a small area of north-east Africa from Kenya north of the Guaso
Nyiro River throughout Somalia, probably extending into the Ogaden of extreme
south-east Ethiopia. It is likely that the range of this species impinges on
that of P. africanus in the Berbera region of north Somalia and, possibly,
north-eastern Kenya and south-eastern Ethiopia, but it is not known whether
true sympatry or intergradation between these populations occurs in these
areas (Grubb, this vol.). Reliable records of the historical distribution of
warthogs in the Cape Province are sparse (du Plessis, 1969; Skead, 1980,
1987), but they were reported as far south as the Sundays River near
present-day Port Elizabeth (Sparrman, 1789). Further inland, warthogs were
recorded from the foot of the Zuurberg hills (Barrow, 1801) and in the
Beaufort West district of the Karroo (Lichtenstein, 1815). Rookmaker (1989)
provided further records of warthogs in south-central Cape Province, based on
archives and literature up till 1790. Their former range also extended across
the Orange River into the northern Cape and Orange Free State, where they
were recorded from the sour-grass plains (Cumming, 1851) and along the Riet
River (Bowker, cited in Mitford-Barberton, 1970), both localities south-west
of present-day Blomfontein; and near the Rhenoster River, a tributary of the
Vaal River, in the northwestern Orange Free State (Baines, cited in Kennedy,
1964). However, their occurrence in this region, where winter temperatures
may fall to freezing, clearly depended on the availability of vleis (marshy
depressions) and riverine foraging sites, as well as night-time shelter in
aardvark burrows, rock crevices and reedbeds, but some localities would have
been too cold. Moreover, relatively lush riparian corridors along seasonal
watercourses enable warthogs to penetrate or reside in arid regions, as
evinced by recent sightings of these animals in reedbeds at the mouth of the
Ugab River in Namibia (B. Loutit, pers. comm.). Warthog numbers in the Orange Free State and much of
the Cape Province had probably already been substantially reduced by
uncontrolled hunting when the infamous rinderpest epizootic that began in the
horn of Africa in 1889 reached the Cape in 1896 (Mack, 1970). Consequent
mortality of cattle and game across the continent was catastrophic
(Plowright, 1982). Warthogs are highly susceptible to rinderpest and the
epizootic was so virulent in southern Africa that it burned itself out
completely (Scott, 1981). Because the reproductive potential of warthogs is
high, their populations can recover quickly even after being decimated, but
documentary evidence of the post-rinderpest situation vis-…-vis warthogs in
the Orange Free State and Cape Province is lacking. Uncontrolled hunting and
encroaching settlements may have eliminated warthog survivors even before the
rinderpest, especially where habitats were marginal, and salient habitat
factors may have changed. Whatever the causes, warthogs became extinct in the
Orange Free State and over most of their former range in the Cape. Unfortunately, hopes that the warthogs surviving in
the far northern Cape (Meester et al.,
1986; Skinner and Smithers, 1991), including the Molopo River on the Cape
side of the Botswana border (P. Novellie, pers. comm.) and the Alletasrust
area of the Vryburg district (G. Fletcher, pers. comm.), may be living
representatives of this species have also proved groundless as these animals
have fully functional incisors like the P.
africanus stock. Moreover, there is no evidence that the far northern
Cape warthogs derive from sources other than the ancestral populations that
would have had a much wider historical distribution southwards and into the
Transvaal and Botswana. The common warthog still has a very wide range
extending from Senegal and extreme south Mauritania in the north-west to
northern Ethiopia and Djibouti in the north-east, to Namibia, the northern
Cape Province and Natal in the south. However, the continuous expansion of
the Sahel-zone has resulted in a marked contraction in the species' former
range in the north since the early 1980's, and accounts for its probable
extinction in Mali and Niger (J. Newby, pers. comm.). Recent data on its
status and distribution are lacking from the southern Central African Republic,
most of Zaire (now Democratic Republic of Congo), and from Angola, but elsewhere the species is reported to survive
throughout much of its former range. Indeed, its range is expanding in some
areas, such as Botswana and Transvaal Province, in response to the clearing
of former wooded savannah and the creation of pasture. In addition, warthogs
have been 'reintroduced' in Natal and eastern Cape Province (Skinner and
Smithers, 1991; Mason, 1992; M. Somers, pers. comm.), though this stock could
pose a threat to the genetic integrity of the native populations surviving in
the northern Cape (also see later text). In north-east Algeria, a small
breeding group that escaped from the Annaba Zoo in 1988, seems to have become
established in the vicinity of the city and comprised 25-30 animals early in
1991 (K. De Smet, pers. comm.; Fig. 7). Habitat, Ecology and Behavior Warthogs occur over a wide range of altitudes from
sea-level in the Gambia (A. Camara, pers. comm.) to 3,000 m on the Ethiopian
plateaus (J. C. Hillman, pers. comm.). The distribution of both species is
limited by the availability of suitable forage, cover and, increasingly, by
human pressures. Warthogs occur on treeless open plains and in lightly wooded
savannah, but avoid densely wooded vegetation without grazing. They are
predominantly grazers, though they will also consume sedges, fallen fruits
and certain forbs. During periods of drought they may be able to subsist
without drinking water by rooting for succulent rhizomes and bulbs. Compared to
bushpigs, Potamochoerus larvatus,
warthogs appear much less dependent on the continuous availability of surface
water. For details of the ecology and behavior of warthogs in southern Africa
see Cumming (1975), Kingdon (1982), Mason (1982), Radke (1991) and Skinner
and Smithers (1991). Warthogs are largely diurnal and sleep at night in
burrows, often using aardvark holes. While their body temperatures can
evidently vary within a certain tolerance range (Cumming, 1975), warthogs
usually cope with high temperatures by behavioral strategies, such as
wallowing. Their sparse pelage and usual lack of substantial sub-dermal fat
also facilitate heat dissipation, but these afford poor insulation against
cold, to which warthogs are particularly susceptible. Low resistance to cold
is ameliorated by sheltering in burrows, huddling together and, sometimes, by
constructing grass nests. Infants are particularly vulnerable to cold
exposure and malnutrition during drought, which together with predation and
other mortality factors may result in juvenile survival rates of <50%
during the first year (Mason, 1982, 1990). Lions are the most important
predators of warthogs, probably followed by leopards. Adult warthogs usually
run from wild dogs, but constitute formidable prey to leopards and cheetahs,
which tend to hunt younger animals. By sheltering in burrows overnight, they
largely avoid nocturnal predators, including hyenas, which are nevertheless
wary of adult warthogs. Adult males are not known to be territorial, but
they contest mating priority. They are usually solitary or live in small,
loose bachelor groups, unattached to the small family units, which generally
comprise one to three adult females and their young. One or two mature
daughters may continue to associate with their mothers over several mating
and farrowing cycles, but males generally leave their natal groups before the
age of two years, often forming or joining bachelor groups. Warthogs breed
throughout the year in equatorial regions, but under seasonal climatic
conditions farrowing is cyclical and synchronized with the end of the dry
season or, in regions of higher rainfall spread over most months of the year,
during the short dry season. The gestation period is about 172 days; average
litter size being 3 with a range of 1 - 7 (Mason, 1982). Unlike Potamochoerus
(Vercammen et al., this vol.
Section 4.4) interbreeding with other suids has never been reported, even if
several species live in the same region and use the same waterholes. Threats to Survival As indicated
above the principal causes of mortality amongst free-living populations are
climatic extremes (including low temperatures, excessive rainfall or drought)
and predation. Owing to their preference for open savannahs, warthogs may
benefit from deforestation, though desertification has undoubtedly
contributed to the species' decline in parts of the Sahel. Human persecution in reprisal for crop-raiding, or
overhunting for meat, are probably the most important threats to P. africanus, and the latter factor
undoubtedly contributed to the early extinction of the Cape population of P. aethiopicus. Warthogs are known to
cause serious damage to various crops, most notably rice-fields in Guinea
Bissau and peanut crops in eastern Zaire (now Democratic Republic of Congo;
P. Chardonnet, pers. comm.; J.-P. d'Huart, pers. comm.). Damage to
unspecified crops has also been reported from Gabon, Guinea and Mauritania.
They are also regarded as competitors for grazing on cattle ranches in
southern Africa. Warthogs are easy to hunt and provide a large
carcass. In non-Muslim countries, their meat is highly valued, both for local
consumption and for trade in city markets, though in many countries,
particularly in the west and north, warthogs benefit from the religious taboo
relating to the consumption of pork. However, these taboos do not provide
complete protection against human predation or persecution, since hunting by
Christian and animist groups continues, as in Djibouti (A. Laurant, pers.
comm.), or the Muslims themselves may hunt wild pigs to sell the meat to
local non-Muslims or city markets, as in Senegal (A. Dupuy, pers. comm.) and
Guinea Bissau (P. Chardonnet, pers. comm.). There is some-small scale trade in warthog tusks as
tourist curios in Somalia, Guinea Bissau and Senegal, but no significant
international trade in warthog ivory has been documented to date. It remains
to be seen if the controls on the elephant ivory trade will influence demand
for warthog tusks in the future, as has been suggested (D. Cumming, pers.
comm.). Warthogs are also susceptible to various diseases,
which may seriously affect local populations, as well as making them
important targets for disease control programmes. For example, outbreaks of
rinderpest in Benin in 1981, the Central African Republic in 1983-85, and in
north Zaire (now Democratic Republic of Congo) 1984, are reported to have
resulted in the loss of up to 80% of the populations in these countries (A.
Green, pers. comm.; J. M. Fay, pers. comm.; K. H. Smith, pers. comm.).
Warthogs are a preferred host of the tsetse fly (D. Cumming, pers. comm.),
for which attempted control measures have included costly and controversial
game eradication campaigns. An indication of the scale of the latter is
provided by the recorded total of 67,897 warthogs shot in Zimbabwe between
1933 and 1957/8 (Child & Riney, 1987). Because of the importance of
warthogs as a vector of the tick-borne African swine fever virus (Rautenbach,
1982), which is fatal to domestic pigs, the transport of live warthogs or
their meat is restricted in Botswana, Natal and Zambia (R. C. V. Jefferey,
pers. comm.; P. L. Walker, pers. comm.). Conservation Measures Taken P. africanus is present in most of the
protected areas throughout its extensive range, whereas P. aethiopicus is not known to occur in any protected area at
present. It is possible that the range of the latter species extends into the
only existing reserve in Somalia, Lack Badana National Park (3,340 sq. km),
in the southernmost corner of the country, and even as far as the
Samburu-Isiolo National Reserve (504 sq. km) in Kenya (P. Grubb, pers.
comm.), though its presence in these areas requires confirmation. In theory
hunting is forbidden in all national parks and wildlife sanctuaries, but is
permitted during fixed seasons and/or on restricted permits in some reserves.
However, such permits are rarely issued in most countries, except for
legitimate scientific research purposes or population control. In practice,
however, protective legislation is poorly enforced or totally unenforced in
some countries or parts thereof (e.g. the Central African Republic, Nigeria,
Togo and Zaire (now Democratic Republic of Congo)). Outside protected areas, both species are in serious
decline due to overhunting over most of their former ranges. In general,
hunting regulations are reported to be more frequently violated than
respected in most West and Central African countries, even inside most of the
designated protected areas, though the Gambia and Ghana are among certain notable
exceptions. Apart from Angola and Mozambique, designated national parks and
wildlife reserves are well protected in all southern African countries, but
farmers are free to control warthog numbers outside these areas. As previously stated, the range of P. africanus is slowly spreading
southward due to the 'restocking' of private and government game reserves in
South Africa. This practice, together with accidental releases, has enabled
the species to become established ('naturalized') outside its original range
in Natal, (eastern) Cape Province and in Algeria. Given the very low levels of international trade in
live warthogs and warthog products at the present time, neither species is
included on the CITES Appendices. Captive Breeding Due to their strange appearance, warthogs were among
the first and most popular pigs to be exhibited in western zoos (e.g. in the
Hague in 1765, in London in 1850, Brussels in 1856, in Hamburg between 1862
and 1872, and in Antwerp in 1867 (Vercammen, unpubl.). However, reproduction
has been recorded only relatively rarely and has seldom met the demand
amongst zoos for exhibition animals and it is only recently that serious
attempts have been made to breed this species, e.g. in Frankfurt, Moscow and
Los Angeles Zoos. Nonetheless, warthogs are now the most numerous exotic pigs
in captivity, with the exception of Sus
scrofa, though they continue to fetch high prices on the commercial
market for live animals. The continuing demand for live warthogs amongst some
U.S. zoos has even led to the highly undesirable practice of 'leasing'
exhibition animals by animal dealers and breeders. Most of the warthogs
currently held in captivity originated from East Africa, though no attempts
have been made to maintain the integrity of particular subspecies. However,
most of these animals are certainly P. africanus since, as far as is known,
the only captive P. aethiopicus
currently (1991) in captivity is an adult male, reputedly from northern
Somalia, in a private collection in Qatar (C. Groves, pers. comm.). Additional Remarks Under favorable conditions and in the absence of
large predators, warthog populations are potentially capable of increasing by
up to 39% per annum (Somers and Penzhorn, 1992). As a result, the species is
often kept on game ranches, where it is harvested on a commercial basis, e.g.
in Burkina Faso (C. Spinage, pers. comm.), Zimbabwe (V. Wilson, pers. comm.)
and South Africa, while population numbers in protected areas may have to be
controlled by culling, e.g. in Lengwe National Park in Malawi (R. Bell, pers.
comm.). Conservation Measures Proposed: An Action Plan P. africanus has a vast range wherein numerous
national parks afford adequate protection, although their long-term survival
outside these reserves is rather doubtful given continued hunting pressure
and/or the conversion of former habitat for human settlement and agriculture.
In comparison, P. aethiopicus is
almost certainly extinct in the southern part of its disjunct range, and its
present status in the north is unknown, although warthogs were reported to be
widespread and relatively abundant in Somalia in 1984 (Fagotto, 1984).
Moreover, the occurrence of Somali warthogs has not been confirmed from any
protected area. These considerations are manifest in the following
recommendations, which also address the need for more information on the
systematic relationships of these animals, and their current distribution,
conservation status and utilization by local people over large parts of their
range, where existing data are insufficient for the formulation of practical
management measures at the present time. Priority Projects: Phacochoerus aethiopicus: 1. Conduct field status surveys. Field surveys are required to
determine the present status and distribution limits of this putative species
throughout its relatively restricted remaining range in the Somali Republic
and north-eastern Kenya, possibly extending into the Ogaden of eastern
Ethiopia, in order to formulate management recommendations and conservation
measures for the enhanced future protection of core population areas.
Particular emphasis should also be placed on determining whether this species
is allopatric with P. africanus or whether sympatry or intergradation occurs
at the limits of its range in the latter areas. 2. Conduct field studies of the species' habitat,
ecology and behavior. These studies are important
because the behavioral ecology of this species is virtually unknown and is of
considerable scientific interest, both for comparison with the substantial
data already available on the closely-related P. africanus and because this
species may be one of the most specialized of all living suids. Such studies
should also investigate the species' adaptations to arid environments and the
functional significance of its loss of incisors. Phacochoerus africanus: 3. Conduct field status surveys in northern Ethiopia
and Djibouti. Additional distribution and status
data are required for the most threatened subspecies, P. a. aeliani, which is insufficiently known in Ethiopia and is
almost certainly endangered in Djibouti, with a view to the development of
practical management plans for the enhanced future protection of the (now)
isolated populations in these areas and/or the determination of areas of
intergradation between this subspecies and the nominate P. a. africanus (i.e.
within the easternmost limits of the range of latter form). 4. Collect additional distribution and population
status data from south Central African Republic and Zaire (now Democratic Republic
of Congo). This region is of particular
interest as a transition zone between savannah and rainforest, but available
data on warthogs are scanty. Field investigations and/or additional
questionnaire surveys are therefore required, if only to improve
understanding of the present range of this species and factors controlling
its distribution. 5. Collect distribution and status data from Angola
and Mozambique. Almost no recent data are
available from these countries, due largely to continuing political unrest,
which precludes field investigations. However, it is doubtful if warthogs or
other 'game' animals are adequately protected within the existing protected
areas systems in these countries in the present political climate. Wide-ranging
field surveys should, therefore, be conducted as soon as is opportune.
Following an aerial survey in central Mozambique during 1990, J. L. Anderson
(pers. comm.) reported marked decreases in wildlife populations due mainly to
uncontrolled hunting, but noted freshly used warthog holes indicating the
survival of these animals in some areas. 6. Conduct comparative studies of the ecology and
distribution of P. africanus in
West Africa. Almost all available data on this
species' behavior, ecology and habitat preferences are derived from field
research conducted in East or South Africa. Comparative studies in selected
areas in the westernmost parts of its range (i.e. from Mauritania in the west
to Chad and Central African Republic in the east) would be of considerable
scientific interest and potential importance to its future management in
these regions/countries. 7. Discourage any further introductions of warthogs
in the Cape Province, pending the results of genetic investigations. Warthogs from Natal Province
introduced by the Cape Directorate of Nature Conservation into the Andries
Vosloo Kudu Reserve in the eastern Cape and the Rolfontein Dam Nature Reserve
on the Orange River, could pose a threat to the genetic integrity of
surviving native warthogs in the northern Cape. If significant genetic
differences exist, there may be a case for encouraging control of the
recently introduced populations. P. aethiopicus and P.
africanus: 8. Acquire additional taxonomic material from
selected, critical areas. As previously indicated (see
earlier text; Grubb, Section 4.1, this vol.), a number of taxonomic
questions, such as the affinities of the Phacochoerus spp./ssp. populations
in eastern Ethiopia and north-central Kenya, and the distributional and genetic
relationships between P. aethiopicus and P. africanus in this region can only
be resolved by the acquisition and analyses of additional hard and soft
tissue samples for comparative study. 9. Establish captive breeding programmes for the
most threatened taxa. The stringent veterinary
regulations appertaining to the import and export of wild pigs which apply
throughout the European community and in North America, make it very
difficult to supplement existing breeding stock outside Africa, particularly
given the problem of isolating disease-free animals and the lack of suitable
quarantine facilities in countries of origin. Consequently, the possibility
of developing breeding programmes for both species in Africa merits
consideration, both as a possible source of animals for future
reintroductions and for research and educational purposes. In any event, the
establishment of such programmes for the most threatened taxa, such as P.
africanus aeliani and, especially, P. aethiopicus delamerei, is a priority. 10. Monitor trade in bush meat and tusk ivory. Warthog populations are
potentially susceptible to over-exploitation, particularly along the northern
edge of their ranges. The possibility of commercial markets being created for
warthog ivory, or for their skulls as curios around tourist centers, should
be guarded against. Acknowledgements Grateful thanks are extended to the following
correspondents who completed the African Suiform Survey report forms and
supplied numerous reprints and other data: S. Abou, F. O. Amubode, W. F. N.
Ansell, R. H. V. Bell, O. Bourquin, T. Butynski, P. Chardonnet, B. Child, G.
Davies, I. Douglas-Hamilton, A. Dupuy, F. Fagotto, J. M. Fay, J. M. Fryxell,
M. E. J. Gore, J. M. Grandvergne, A. A. Green, J. C. Heymans, T. Ibrahima, N.
Innocent, R. C. V. Jeffery, A. Laurent, B. Limoges, L. Macky, H. Mertens, J.
Maronga-Mbina, F. E. C. Munyenyembe, J. Newby, B. Y. Ofori-Frimpong, E. Ould
Samba, P. J. J. van Rensburg, M. J. Robillard, J. A. Sayer, K. and F. Smith,
C. A. Spinage, G. Teleki, P. Trenchard, J. Verschuren, S. Vrahimis, J. F.
Walsh, G. and H. Welch, and V. Wilson. William Oliver and Peter Grubb
provided numerous valuable comments on earlier drafts of this manuscript, and
Peter Cuypers was largely responsible for the preparation of the distribution
map. References Ansell, W. F.
H. 1978. Mammals of Zambia. National Parks and Wildlife Service, Chilanga:
pp. 51-52. Barrow, J.
1801. Travels into the Interior of Southern Africa, Vol. 1. T. Cadell &
W. Davies, London: 427 pp. Child, G. F. T.
and Riney, T. 1987. Tsetse control hunting in Zimbabwe, 1919-1958. Zambezia
14 (1): 11-71. Cumming, D. H.
M. 1975. A field study of the ecology and behaviour of warthog. Museum Memoir
No. 7. Nat. Mus. Admin., Harare, Zimbabwe: 179 pp. Cumming, R. G. 1851. A Hunter's Life in South
Africa. Vol. 1. John Murray, London: 388 pp. Dorst, J. and
Dandelot, P. 1970. A Field Guide to the Larger Mammals of Africa, Collins,
London: 287 pp. du Plessis, S.
F. 1969. The past and present geographical distribution of the Perissodactyla
and Artiodactyla in Southern Africa. (Unpubl.) M.Sc. thesis, Univ. of
Pretoria: 333 pp. Fagotto, F.
1985. Larger animals of Somalia in 1984. Environ. Conserv.,12 (3): 260-264. Haltenorth, T.
and Diller, H. 1977. A Field Guide to the Mammals of Africa, including
Madagascar. Collins, London: pp. 29-32. Hillman, J. C.
1982. Wildlife Information Booklet. Dept. 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 34, Natal Parks Board,
Pietermaritzburg: 1-11. IUCN/UNEP 1987.
The IUCN Directory of Afrotropical Protected Areas. IUCN, Gland: 1034 pp. IUCN 1988.
Conservation et utilisation nationelle des ecosystemes forestieres en Afrique
Centrale. Rapport National Cameroun, IUCN, Gland. Joubert, E. and
Mostert, P. K. N. 1975. Distribution patterns and status of some mammals in
South-West Africa. Madoqua 9 (1): 5-44. Kennedy, R. F.,
ed. 1964. Thomas Baines' Journal of Residence in Africa 1842-1853. Vol. 2.
The Van Riebeeck Society, Cape Town. Kingdon, J.
1982. East African Mammals, Vol. IIIB. Academic Press, London: pp. 230-249. Lichtenstein,
W. H. C. 1815. Travels in Southern Africa, in the Years 1803, 1804, 1805 and
1806. Vol. 2 (transl.). The Van Riebeeck Society, Cape Town. Limoges, B. In
press: Wildlife census in Guinea Bissau. Mack, R. 1970.
The great African cattle plague epidemic of the 1890s. Trop. Anim. Hlth.
Prod. 2: 210-219. Mason, D. R.
1982. Studies on the biology and ecology of the warthog, Phacochoerus aethiopicus sundevallii Lönnberg, 1908 in Zululand.
(Unpubl.) D.Sc. thesis, Univ. Pretoria, South Africa: 335 pp. Mason, D. R.
1990. Juvenile survival and population structure of blue wildebeest and
warthogs in the Central Region of the Kruger National Park during the
mid-summer drought of 1988/89. Koedoe 33 (1): 29-45. Mason, D. R.
1992. Origin of warthogs on Rooipoort Estate (de Beers Consolidated Diamond
Mines Ltd.) and on Vaalbos National Park, Cape Province. (Unpubl.) rep. to
IUCN/SSC Pigs & Peccaries Specialist Group: 1 p. Meester, J. A.
J., Rautenbach, I. L., Dippenaar, N. J. and Baker, C. M. 1986. Classification
of Southern African mammals. Transvaal Museum Monograph No. 5. Transvaal
Museum, Pretoria: 359 pp. Mitford-Barberton,
I. 1970. Comdt. Holden Bowker. Human & Rousseau, Cape Town. Plowright, W.
1982. The effects of rinderpest control on wildlife in Africa. Symp. Zool.
Soc. Lond. 50: 1-28. Radke, R. 1991.
Monographie des Warzenschweines (Phacochoerus
aethiopicus). Bongo, Berlin 18: 119-134. Rautenbach, I.
L. 1982. Mammals of the Transvaal. Ecoplan Monograph No. 1, Ecoplan,
Pretoria: 211 pp. Rookmaker, L.
C. 1989. The Zoological Exploration of Southern Africa 1650-1790. A. A.
Balkema, Rotterdam and Brookfield: xii + 368 pp. Roure, G. 1968.
Animaux Sauvages de Haute-Volta et des Pays Voisins. (Unpubl.) rep.,
Direction des Saux et Forets, Ministère de l'agriculture, Ouagadougou: 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. Schmidt, C. R.
1988. Schweine-Säugetiere, Band 5. In: B. Grzimek (ed.), Grzimek's
Enzyklopädie, Kindler-Verlag, Munich: 17-47. Sclater, W. L.
1900. The Mammals of South Africa, Vol. 1: Primates, Carnivora and Ungulata.
R. H. Porter, London: 324 pp. Scott, G. R.
1981. Rinderpest. In: J. W. Davis, L. H. Karstad & D. O. Trainer (eds.),
Infectious Diseases of Wild Mammals. Iowa State Univ. Press, Ames: pp. 18-30. Skead, C. J. 1980.
Historical Mammal Incidence in the Cape Province, Vol. 1: The Western and
Northern Cape. Cape Directorate of Nature & Environmental Conservation,
Cape Town: pp. 381-391. Skead, C. J.
1987. Historical Mammal Incidence in the Cape Province, Vol. 2: the Eastern
Half of the Cape Province, Including the Ciskei, Transkei and East
Griqualand. Cape Directorate of Nature & Environmental Conservation, Cape
Town: 112 pp. Skinner, J. D.
and Smithers, R. H. N. 1991. The Mammals of the Southern African Subregion, 2nd
Ed. University of Pretoria Press, Pretoria: pp. 594-598. Smithers, R. H.
N. and Wilson, V. J. 1979. A checklist and atlas of the mammals of Zimbabwe.
Mus. Memoir No. 9, Nat. Mus. Admin., Harare, Zimbabwe: pp. 113-115. Somers, M. J.
& Penzhorn, B. L. 1992. Reproduction in a reintroduced warthog population
in the eastern Cape Province. S. Afr. J. Wildlife Res. 22(3): 57-60. Sparrman, A.
1789. A Voyage to the Cape of Good Hope, Towards the Antarctic Polar Circle,
and Round the World: but Chiefly into the Country of the Hottentots and
Caffres, from the Year 1772 to 1776. Vol. 2. Morison & Son, Perth: 260
pp. Yalden, D. W.,
Largen, M. J. and Kock, D 1984. Catalogue of the mammals of Ethiopia.
Monitore Zoologico Italiano, 4: 67-221. |
|
Next: Chapter 4.3 – The
Forest Hog |