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Pigs, Peccaries and
Hippos Status Survey and Action Plan (1993) Chapter 5.5 The Bearded Pig (Sus barbatus) Julian O.
Caldecott, Raleigh A. Blouch and Alastair A. Macdonald. Status and Action Plan Summary Status categories
2-3 - the nominate subspecies from Borneo, S. b. barbatus, is still widespread but declining in numbers; the
western subspecies from Peninsular Malaysia and Sumatra, S. b. oi, and the eastern subspecies from Palawan and neighboring
islands, S. b. ahoenobarbus, are
both rare. In Borneo, the
dipterocarp forests should be deliberately managed for a variety of non-wood
as well as wood outputs, which will benefit bearded pigs if wild meat is one
of the outputs required. This action requires a fundamental rethinking of
forestry management strategy. Conservation areas need to be maintained, and
the communal forest system expanded, thereby retaining intact forest areas
for the benefit of rural communities and with them, local bearded pig
populations. Detailed, long-term investigation of the behaviour of identified
pigs is necessary to resolve outstanding questions of social structure and
home range use. In Peninsular or
West Malaysia, (northern) Sumatra, Bangka and the Riau Islands, field surveys
are needed to correct a lack of information on the distribution and status of
S. b. oi and the habitats where
they can be expected to survive, which is hampering measures to conserve
bearded pigs in these regions. Unlike either of the other two subspecies,
these animals are everywhere sympatric with S. scrofa, which may be competitively advantaged by human induced
changes in its environment and whose relative abundance may have a negative
influence on local attitudes to the management requirements of the rarer
form. There is similar
lack of recent information on the distribution and status of the Philippine
endemic, S. b. ahoenobarbus, which
has by far the most restricted range of the three, currently recognized
subspecies. The present status of these animals on Balabac is unknown, but
they remain quite widely, if patchily, distributed on the Calamian Islands
(Busuanga, Culion and Coron) despite intense hunting pressure. Bearded pigs
are also reported to be intensively hunted on Palawan, though precise data is
lacking on their range there and any future fieldwork on this island is
likely to be seriously compromised by the presence of armed rebels. All of
these and other related problems are addressed in the proposed action plan
for this species, which also recognizes the need to resolve the now rather
confused systematic relationships between the three (Sundaic) forms of
bearded pigs the closely allied wild pigs of the neighboring Wallacian
subregion, i.e. the eastern Philippines' 'philippensis'
and 'cebifrons', and the Sulawesi
warty pig, S. celebensis. Introduction Adult bearded pigs
are characterized by their relatively large body size, a degree of sexual
dimorphism, an elongated skull, long legs, a 'bearded' jaw (gonial tuft) and
sparse body hair (Pfeffer, 1959). In addition, they are well known for their
most spectacular collective attribute - lemming-like population eruptions -
which have been recorded in different parts of Borneo since early this
century (Shelford, 1916). Equally interesting migratory behaviour was
described from Malaya in the 1940's and 1950's, but by the 1960's the camphor
wood forests whose fruiting seemed to stimulate this behaviour had been
felled (Caldecott, 1991). The result was a long period when eruptions and
migrations were known to be a feature of the species, but they could not be
described in the context of a broad appreciation of the bearded pig's
ecology. Following Groves
(1981) and Groves and Grubb (this vol.), three subspecies are currently
recognized. The type race, S. b.
barbatus, is confined to Borneo (Kalimantan, West Malaysia and Brunei),
though recent reports indicate that it may also occur on some neighboring
islands, including Sibutu and Tawi-Tawi in the Sulu Archipelago, Philippines
(Oliver et al., Chapter 5.6, this
vol.). The closely related race from West Malaysia, Sumatra, Bangka and the
Riau Islands, was separated as a distinct subspecies, S. b. oi, by Groves (1981), though this was questioned by Mudar
(1986), who proposed it should be lumped with the nominate race. In either
event, ecological and behavioral, as well as morphometric, similarities
suggest that these 'Sundaic' forms are the most closely related. This name
refers to Sundaland, the continental shelf, which was exposed at times during
the Pleistocene and which thereby, linked Malaya with Sumatra and Borneo and,
at its periphery, with Java and Palawan (Whitmore, 1981, 1987, 1988). On Java
S. barbatus is replaced by S. verrucosus, but there is a third
subspecies, S. b. ahoenobarbus, on
Balabac, Palawan and the Calamians Group. Groves (1981) also tentatively
recognized two additional subspecies of bearded pigs from the central and
easternmost islands of the Philippines (i.e. S. b. cebifrons and S. b.
philippensis, respectively), but recently acquired evidence suggests that
these forms should be treated as separate, though closely allied, species
(Grubb and Groves, this vol.; Oliver et
al., op cit.). Link to Fig. 13: Approximate
former and present distribution of the bearded pig, Sus barbatus ssp. Former and Present Distribution The bearded pig
occurs in archipelagic South-east Asia, extending from the large landmasses
of the Sunda shelf (Peninsular Malaya, Sumatra and Borneo) to Palawan and
neighboring islands in the west Philippines. In Malaya and Sumatra, it is
sympatric (though not necessarily syntopic) with the Eurasian wild boar, S. scrofa. The archeological evidence
suggests that the bearded pig was fairly plentiful and widespread in the
Malayan Peninsula about 1500 to 2000 years ago (Gibson-Hill, 1950). Herds of S. b. oi have been seen in the
vicinity of the Taman Negara National Park in central north-east Malaya as
recently as 1981 (Johns, 1983), and this extensive forest block presumably
represents an important refuge for the subspecies. On the other hand, annual
movements of bearded pig populations in Malaya appear to have been associated
with the regular fruiting of camphor wood forests, which once occupied
several thousands of square kilometers in the south- east and north-east of
the Peninsula. Formerly, bearded
pigs of this subspecies were also found in northern (Medan), central
(Indragiri) and southern (Lampung) Sumatra (Groves, 1981). However, a field
survey of the larger mammals revealed that they had all but disappeared from
the southern quarter of the island, where they are now reported to survive
only in the Lebong Hitam forest across the straits from Bangka Island
(Blouch, 1984). Not coincidentally, deforestation in Sumatra during the past
30 years has been heaviest in the south, and the relatively small amount of
remaining forest there is now highly fragmented. In central Sumatra bearded
pigs were nowhere abundant in 1984, although local people in several areas
reported occasional large traveling herds (Blouch, unpubl.). There is no
recent information on the status of these animals in the northern end of the
island, north-west of Medan. Recent information on their status on Bangka
Island and in the Riau Archipelago (Bintang Island), where they are known to
have occurred (Groves, 1981), is also lacking. Archaeological
studies in Sarawak indicate the human hunting of bearded pigs was undertaken
since before the Palaeolithic (Medway, 1958, 1977). This (type) subspecies
remains widely distributed in Borneo and is still relatively abundant in some
areas. It also occurs on some offshore islands, including Karimata (off west
Kalimantan), where it was recently reported to be common (Bekti et al., 1991). S. b. barbatus is not, therefore, particularly threatened at the
present time. However, the continued ability of the bearded pig to provide an
abundant source of meat to the tribal inhabitants of the interior is now
threatened by deforestation and selective logging. Since bearded pig
productivity is so dependent on ecological events (see below), this can be
regarded as only one among many consequences of a broader abuse of the
Bornean forest estate by the timber industry. From reports
obtained recently (W. Oliver pers. comm.; Oliver et al., Chapter 5.6, this vol.), it appears that bearded pigs
periodically cross the strait between the north-easternmost tip of Borneo
(Sabah) to the Sibutu and Tawi-Tawi, the southernmost islands of the Sulu
Archipelago, in south-west Philippines. This implies genetic continuity
between these locations and also another (though non-endemic) pig taxon to
the Philippines' list. However, it is not known if there is any correlation
between the (as yet poorly documented) incidences of pigs crossing this
strait and the periodic eruptions and migrations of these animals on the
Bornean mainland (see below). The third
subspecies, S. b. ahoenobarbus, is
endemic to the Philippines, where it is confined to Balabac, Palawan and the
Calamian Islands (Groves, 1981; Rabor, 1986), which collectively comprise the
'Palawan Faunal Region' (Heaney, 1986), the westernmost edge of the Sunda
Shelf. There is relatively little information on the status of these animals
on Balabac, though it is reported to survive in most still-forested areas on
Palawan (McGowan, 1987) and on the three principal islands, Busuanga, Culion
and Coron, in the Calamian Group (Oliver, 1992; Oliver and Villamor, 1993). Habitat, Ecology and Behavior The natural
vegetation in all areas where bearded pigs are found is dominated by tropical
evergreen rainforest, but within this broad category the animals utilize a
wide variety of habitat types, ranging from beaches to upper montane cloud
forests. The carrying capacity for bearded pigs no doubt varies greatly from
habitat to habitat within the rainforest, depending on soil, drainage,
elevation and floristic and phytochemical composition of the vegetation.
Population density is also radically variable over time, so it is hard to
determine consistent differences between habitats in this respect. Bearded pigs consume
roots, fungi, invertebrates in soil and rotting wood, small vertebrates,
turtle eggs, carrion, and items from at least 50 genera and 29 families of
plants. Fruit supply is believed to have particular influence in determining
growth rate, fat deposition and reproduction, with the oil-rich seeds of
members of the tree families Fagaceae (oaks and chestnuts) and
Dipterocarpaceae (dipterocarps) being especially important in this regard. Of
these, the oaks are significant because of their relatively continuous or
regular fruiting behaviour, and also because they can come to dominate
submontane habitats. The dipterocarps are often dominant in lowland and hill
forests, and strongly influence food availability for terrestrial seed-eaters
by characteristically synchronized flowering and mast-fruiting behaviour
(Caldecott, 1988; Pfeffer, 1959; Pfeffer and Caldecott, 1986; Davies and
Payne, 1982; Janzen, 1974; Jessup et
al., 1982; Leighton and Leighton, 1983). Large-scale
population movements by bearded pigs have often been reported in Malaya
(Allen, 1948; Kempe, 1948; Hislop, 1949, 1952, 1955) and Borneo (Shelford,
1916; Banks, 1931, 1949; Banks in Hislop, 1955; Pfeffer, 1959; Davies and
Payne, 1982; Caldecott and Caldecott, 1985; Caldecott, 1988a, 1991). Pigs are
described as moving consistently in one direction, in scattered or condensed
herds, over a broad or narrow front, and over a period of several days, weeks
or months. The animals are variously described as being in good, poor or very
poor physical condition, sometimes accompanied by piglets and sometimes not,
and regularly swimming across rivers, sometimes coastal bays and even out to
sea. In some cases, the population is said to retrace its route later, or to
follow a circular course to return whence it originally came. The distances
traveled appear to vary greatly. Pfeffer (1959) described annual, apparently
unidirectional, population movements in Kalimantan involving distances of
250-650 km, while Davies and Payne (1982) refer to annual reversible
movements over tens of kilometers in Sabah. The approximate population tracks
given by Caldecott (1988a) suggest rates of travel of 8-22 km/month sustained
over at least 4-8 months as part of larger cyclical movements in interior
Sarawak. Some reports indicate that such population migrations begin or end
in particular locations where abundant food may be found. Thus, Davies and
Payne (1982) linked movements to seasonally-fruiting Dinochloa bamboo groves, while Caldecott (unpubl.) reinterpreted
historical accounts so as to link Malayan bearded pig movements with
predictable fruiting in camphor wood (Dryobalanops
aromatica) forests. Caldecott (1988a) also described what appeared to be
regular use of fruiting montane oak (Lithocarpus)
forests in the upper Baram area of Sarawak. In Sumatra bearded
pigs also exhibit large scale population movements, but reports are anecdotal
and often contradictory. Groups of up to 300 individuals are said to embark
on long migrations, arriving at a given location at irregular intervals,
sometimes as often as once a year but more frequently once every two to four
years. In the highlands these movements do not seem to have any relation to
the seasons, but in the lowlands the pigs tend to move out of the inundated
forests to higher ground in the rainy season and back again in the dry season
(Blouch, 1984). The relationship between these movements and the cycles of
mast production has not been investigated. The primary
ecological adaptation of the western races of bearded pigs, to the pursuit of
fruiting peaks within the large-scale phenological mosaic of dipterocarp
forests, may not be a feature of the Philippine subspecies, since 'eruptions'
and 'migrations' of the kind seen in Borneo and Malaya have not been reported
there. However, bearded pig populations exhibit a range of different states,
which can be summarized as follows: ·
Dispersed, static populations
exploiting small, dispersed, unpredictable and discontinuous 'background'
food sources. Low breeding and growth rates possible. Local movements only.
(E.g.: typical mixed dipterocarp forest in Borneo between generalized
fruiting episodes). ·
Small to medium populations exploiting
concentrated, predictable and continuous 'target' food sources. High breeding
and growth rates possible. Local movements only. (E.g.: Koompassia-Burseraceae forest in Malaya). ·
Small to medium populations, with
members aggregating to exploit large, dispersed, unpredictable food sources.
Breeding and birth rates depend on success of matching movements to fruiting
within a dynamic phenological mosaic. Short to medium-range movements. (E.g.:
typical mixed dipterocarp forest in Borneo between generalized fruiting
episodes. ·
Small to large populations moving
regularly to exploit concentrated, predictable and discontinuous target food
sources. Breeding and growth linked to activity of food sources. Short-range
to long-range movements. Size of population varies from year to year
depending on background food supply. (E.g.: Dinochloa association in Sabah, or Dryobalanops aromatica association in Malaya). ·
Large and expanding population
exploiting an exceptional supply of background food available over a period
sufficient for several litters to be raised to sexual maturity. High breeding
and growth rates characteristic. Long range movements. (E.g.: interior of
Sarawak in 1954, 1959, 1983 and 1987). ·
Very large and collapsing population
having exceeded background food supply. Low breeding and high death rates.
Increasingly desperate long-range movements. (E.g.: starving herds reported
from Malaya and Borneo). The basic social
structure is that of the major social unit being the mother family, a female
and her litter. These units often join up, and much larger aggregations are
formed occasionally, with scores or even hundreds of pigs traveling together.
Fully adult males seldom associate with the natal groups. Age at first
pregnancy presumably varies in the wild from about 10-20 months. In any one
area, the rut coincides with synchronized flowering in the forest, with the
timing being centered on the transition between late flowering and early
fruit formation. Falling petals therefore offer a potential visual cue. A
certain nutritional status may have to have been attained by females before
they become responsive to whatever stimulus acts to trigger mating. Pregnant
females had a median fatness index (finger-widths of fat depth at the
shoulder) of 1.5, while rutting males scored zero by this measure (n = 19,
32). Gestation length is
not known but is estimated at 90-120 days, based on the interval between rut
and the ensuing birth-peak. Birth occurs within a nest, which is constructed
of vegetation by the mother, and which is occupied by her and the new piglets
for a week or so. Data from hunter interviews indicated that the median
number of piglets accompanying an adult female (n = 53) was 7, which was the
same as the median number of fetuses counted in dead females (n = 8). Abbot
in Davies (1962) reported a slightly higher median of 9 fetuses per female (n
= 5). Litter size is very variable in part because of the influence of female
size: small mothers typically have 3-4 piglets in a litter, while large ones
have 10-12. Elsewhere, the range in litter size has been given as 3-11
piglets (National Research Council, 1983). Fat reserves in the
mother are used up quickly during lactation, and females accompanied by small
piglets are almost invariably thin or very thin. Those with large piglets are
fatter, and have presumably gained weight after weaning. This fattening
process seems to depend on what fruit is available, with dipterocarp seeds
and acorns having most impact. If these are abundant, it seems likely that
two litters can be raised by a female within a year. Threats to Survival The unsustainable logging
of dipterocarps in Bornean forests will change the underlying ecology of the
island, probably in such a way as to prevent bearded pigs from exhibiting in
future the mass population eruptions and movements of the kind observed
during the 1950's and 1980's. These phenomena are no longer seen in areas
where extensive logging has already occurred. The Sundaic bearded pig may be
said to be consummately adapted to life in almost limitless dipterocarp
forests. It is possible that the demise and fragmentation of Borneo's forests
will allow wholesale invasion of the island by S. scrofa, which could then displace S. b. barbatus from much of
its former range. The same may be said for Malaya where several thousands of
square kilometers of camphor wood forest have now been virtually destroyed,
and the integrity of forest cover throughout the Peninsula is so disrupted
that long-distance movement by forest-dwelling mammals is no longer possible
in many areas. Meanwhile, a more
sedentary population of bearded pigs, apparently associated with
continuously-fruiting, Koompassia-Burseraceae
forests in western Malaya, is probably endangered by hunting and habitat
destruction. The habitat changes experienced by the Peninsula since the
Second World War have almost certainly favored S. scrofa over S. barbatus,
and the latter species is believed to be in serious jeopardy as a result. The
same can also be said of Sumatra, where habitat disturbance has been at least
as extensive as in Malaya and where a comparison between the current
distribution of bearded pigs and that of the remaining native forest supports
the contention that the species cannot long survive the reduction and
fragmentation of these habitats. The same situation probably applies to
Bangka and the Riau Archipelago where habitat disturbance has been at least
as extensive as in Sumatra. Wildlife protection
measures are so limited, and hunting so rife, that there is increasing
concern about the status of all wild pig populations in the Philippines.
McGowan (1987) concluded that the future prospects for largest population of S. b. ahoenobarbus on Palawan were
poor if the species were limited to relatively undisturbed lowland forest.
Palawan still supports the highest percentage (59%) of forest cover of any of
the larger islands in the Philippines, although almost all of the island's
forests are subject to logging operations, despite their low commercial value
(Quinnell and Bamford, 1988). Palawan is being rapidly deforested for timber
extraction and agricultural expansion. The construction of logging roads has
also facilitated access to formerly remote areas, which, together with the
depressed economy and relative high price of meat, has exacerbated hunting
pressure and the increased use of such (non-traditional) hunting methods as
pig bombs (McGowan, 1987). There is no information on the current status of
these animals on Balabac, but a recent (February 1992) survey has revealed
that they remain patchily distributed on each of the three principal islands
of Busuanga, Culion and Coron in the Calamian Group (W. Oliver pers. comm.;
Oliver and Villamor, 1993). Conservation Action Taken As far as is known,
little or no action has been taken with the specific intention of conserving
these animals anywhere within their range. In Sumatra and Peninsular Malaysia
this is at least partly due to predominantly Moslem populations, which
consider all pigs to be unclean and pay little attention to them. In
addition, the distinction between S.
scrofa and S. barbatus is
seldom appreciated, and the relative abundance of the former has probably
tended to obscure any declines in the populations of the latter. In Peninsular
Malaysia, the species survives in the Taman Negara National Park (4,343 sq.
km), the only protected area that is likely to be large enough to support a
viable population. In Sumatra, bearded pigs are known to occur in the large
Kerinci-Seblat National Park (14,000 sq. km.) and in Berbak Game Reserve
(175,000 ha), and they are likely to survive in some other protected areas,
though surveys are needed to confirm this. As previously
stated, the Bornean S. b. barbatus remains widely distributed and it occurs
in numerous protected areas in Kalimantan, Sarawak, Sabah and Brunei. In
direct contrast, it remains uncertain whether the eastern subspecies, S. b. ahoenobarbus, even occurs in the
only existing protected area within the core area of its range on Palawan,
i.e. the relatively tiny St. Paul's Subterranean River National Park (3,590
ha) (Cox, 1988), though a small population (c. 150 individuals; J. Gapuz
pers. comm. to W. Oliver) is protected in the Calauit Island Game Preserve
and Wildlife Sanctuary (3,400 ha), off N. Busuanga in the Calamian Islands. Captive Breeding Bearded pigs have
been exhibited only rarely in captivity, and few captive births have been
recorded. In recent years, a trio of S.
b. oi was kept in the Singapore Zoological Gardens, but these have since
died without breeding. During the population eruption of l983, many villagers
in Sarawak obtained S. b. barbatus
piglets by catching them from boats while they were swimming across rivers
with their families. The main feature reported was how difficult it was to
prevent the escape of these piglets, since they were easily able to climb out
of pens designed to hold domestic pigs. A majority of the captives therefore
escaped within a few days. A small numbers of S. b. ahoenobarbus are maintained in small zoos and private
collections in the Philippines, though no attempts have yet been made to
start a properly structured breeding program with any of these animals. Conservation Measures Proposed:
An Action Plan Given the relatively
wide, but highly fragmented distribution of this species in four countries,
the varying conservation status of the currently recognized subspecies and
various conservation problems confronted, any Action Plan for the species as
a whole must address an array of socio-economic and ecological issues, as
well as the more immediate research and management priorities, where these
are known. In Borneo, for example, overall conservation priorities should be
directed towards the deliberate management of dipterocarp forests for a
variety of non-wood outputs (including game meat species, of which the
bearded pig is probably the most important) as well as for wood production,
rather than the promulgation of activities designed to benefit the wild pigs
in particular. The situation for
the western subspecies, S. b. oi,
in Sumatra and Peninsular Malaysia, and the eastern subspecies, S. b. ahoenobarbus, in the Palawan
region, are more problematic than in Borneo. Both of these subspecies are
already far less numerous than S. b.
barbatus and their habitats are greatly reduced and increasingly
fragmented. S. b. ahoenobarbus is probably the most sedentary of the three,
but it also has by far the smallest range. In common with the Bornean race,
it is also intensively hunted throughout its restricted distribution. By
comparison, S. b. oi is not an
important resource to local people (except perhaps to a few scattered
aboriginal tribals) owing to the local predominance of Islam in Sumatra and
Peninsular Malaysia, and there is therefore little perceived economic
incentive to conserve it. However, this subspecies also differs from
ahoenobarbus and barbatus in that it is naturally sympatric with wild S. scrofa, which is probably
competitively advantaged by human-induced changes in the environment. Nonetheless, the
available information on these rarer forms is insufficient to enable
intelligent recommendations at the present time, or even to identify the most
important populations with a view to the development of management plans for
their enhanced future protection. The foremost priorities for these taxa
must, therefore, be directed towards field surveys and other basic research
to determine, amongst other things, where they still occur, how far they move
and why, which habitats are most critical, and whether or not they are able
to survive in logged over forests. The principal
objectives and priority projects for this species can therefore be summarized
as follows: Objectives: 1. To initiate, or otherwise promote, further
field status surveys and other studies on topics relevant to the future
management needs of these animals. 2. To promote the enhanced future protection
of the most threatened subspecies/populations by increasing the number and
size of existing reserves, and/or the effectiveness of protective measures,
in those key areas where the protected areas network is inadequate to ensure
the survival of representative taxa/populations. 3. To design and implement particular,
practical conservation management initiatives, including captive breeding,
directed towards the most threatened forms, etc. 4. The promotion of conservation management
policies designed to ensure the sustainable utilisation of wood and non-wood
products, which would be of both direct and indirect benefit to game meat
species, including the wild pigs. Priority Projects: 1. Conduct field status surveys on Balabac,
Palawan and associated smaller islands. These
surveys should be designed to complete the distribution and status survey
recently initiated in the Calamian Islands, in order to determine the nature
and magnitude of threats to the smallest subspecies, S. b. ahoenobarbus, which also has by far the most restricted
range. These surveys should also be conducted with a view to the development
of recommendations for the enhanced future protection of selected populations
and, if necessary, the formulation of management strategies to enable the
continued harvesting of these animals in non-protected areas on a sustainable
basis. Particular priority should be given to the survey of Balabac, where
any remnant populations are likely to be seriously threatened. This is not to
understate the importance of main stronghold for this taxon on Palawan, where
surveys are also urgently required, though field investigations are likely to
be precluded by the presence of insurgents in some areas. 2. Field status surveys in selected parts of West
(Peninsular) Malaysia, (northern) Sumatra, Bangka and the Riau Islands. These
surveys are required to determine the distribution and status of the western
subspecies, S. b. oi, and the
habitats in which they may be expected to survive in competition with the
sympatric, S. scrofa. Further
research on basic biological questions relevant to the future management of
this subspecies should also be supported, particularly those relating to its
habitat requirements, population movements, response to commercial logging
activities, etc. 3. Assist the development of deliberate
management policies in the remaining dipterocarp forests of Borneo for a
variety of non-wood (e.g. game meat, of which S. barbatus is a predominate source) as well as wood outputs. This
is proposed as one feature of an 'Extended Variable Management System' for
these forests (Caldecott, 1988b). Placing Bornean forestry on a sustainable
basis, however, would demand fundamental reforestation at unprecedented cost
to local economies. Failing a forestry investment program sufficiently
intense to achieve an adequate rate of change, priorities for bearded pigs in
Borneo revolve around maintaining protection in certain conservation areas,
and expanding the communal forest system whereby intact forest areas are
retained for the benefit of rural communities and, with them, local bearded
pig populations. 4. Promote detailed, long-term investigations
of the behaviour of known individual pigs in circumscribed study areas. Such
studies are necessary to resolve outstanding questions of social structure
and home range use and are of direct relevance to the development of any
management plans intended to ensure the maintenance of viable populations of
this species over the longer-term and, hopefully, the perpetuation of their
phenomenal population cycles and associated migratory behaviour. 5. Assist development of local
conservation-education and applied research initiatives in selected, priority
areas. The
historical, and in some places continued, significance of these pigs as a
basic economic and cultural resource to many ethnic groups, and their
potential value as classic 'indicator' species for forest management policy,
is widely unappreciated or even countered by religious prejudice. These factors
should be addressed by the production and distribution of
conservation-education materials and the dissemination of information to
relevant decision and policy making bodies. This process would be greatly
facilitated by the promotion of more localized research into aspects of the
biology, ecology and human utilisation of these animals, particularly in
those areas where the species (for whatever reason) remains poorly known
and/or where sympatry with S. scrofa occurs. 6. Promote development of properly structured
captive breeding programmes for the rarest subspecies, S. b. ahoenobarbus and S.
b. oi. Although
captive breeding is not thought likely to materially influence the survival
prospects of these taxa in the near future, it may well constitute an
important contribution over the longer-term, as well as providing a
potentially invaluable resource for further research into various aspects of
the species' biology and behaviour. Acknowledgements Much of the
information presented on the Bornean pigs was gathered during the senior
author's five year involvement with the National Parks and Wildlife Office of
the Sarawak Forest Department. This work was funded by the Leverhulme Trust,
World Wildlife Fund - Malaysia, and the L. S. B. Leakey Foundation. A large
mammal survey funded by WWF-International provided much of the information on
the Sumatran pigs. Other results were obtained during studies supported by
the University of Edinburgh, the Wellcome Trust, the Carnegie Trust for the
Universities of Scotland, the Royal Zoological Society of Scotland, the Pig
Development Co. and the Cotswold Pig Development Co.. The hospitality and
assistance of the Director and staff of Singapore Zoo is also gratefully
acknowledged. William Oliver provided valuable comments on earlier drafts of
this text, and Paul Vercammen and Peter Cuypers kindly prepared the range
maps. References Allen, E. F. 1948. The bearded pig. Malayan
Nature J., 3: 98-99. Banks, E. 1931. A popular account of the
mammals of Borneo. J. Malayan Branch of the Royal Asiatic Soc., 9: 1-139. Banks, E. 1949. Bornean Mammals. Kuching
Press; Kuching, Sarawak. Bekti, S., Chaerul, S., Yanuar, A., Iwan, D.,
Sutrisno, D. and Dody, A. 1991. Survey pendahuluan mengenai status kera merah
(Presbytis rubicunda carimatae) dan
hidupan liar lainnya di bagian tenggara pulau Kerimata - Kalimantan Barat.
(Unpubl.) rep., Indonesian Wildlife Operation. Blouch, R. A. 1984. Current status of the
Sumatran rhino and other large mammals in southern Sumatra. (Unpubl.) Project
3303 Report No. 4 to IUCN/WWF Indonesia Programme, Bogor: 39 pp. Caldecott, J. O. 1988a. Hunting and Wildlife
Management in Sarawak. IUCN, Gland, Switzerland: 150 pp. Caldecott, J. O. 1988b. An 'extended' variable
management system for the hill forests of Sarawak, Malaysia. J. Trop. Forest
Sc. 1: 103-113. Caldecott, J. O. 1991. Eruptions and
migrations of bearded pig populations. Bongo, J. Zool. Garten Berlin, 18:
233-243. Caldecott, J. O. and Caldecott, S. 1985. A
horde of pork. New Scientist, 1469: 32-35. Cox, C. R. 1988. The conservation status of
biological resources in the Philippines. (Unpubl.) rep. for The International
Institute for Environment and Development, IUCN, Cambridge: 68 pp. Davies, A. G. and Payne, J. B. 1982. A Faunal
Survey of Sabah. WWF-Malaysia, Kuala Lumpur. Davis. D. D. 1962. Mammals of the lowland
rain-forest of North Borneo. Bull. Singapore Nat. Mus., 31: 1-129. Gibson-Hill, C. A. 1950. A further note on the
bearded pig in Malaya. J. Bombay Nat. Hist. Soc., 47: 632-637. Groves, C. P. 1981. Ancestors for the Pigs:
Taxonomy and Phylogeny of the Genus Sus.
Tech. Bull. No. 3, Dept. of Prehistory, Research School of Pacific Studies,
Australian National University, Canberra: 96 pp. Heaney, L. R. 1986. Biogeography of mammals of
S. E. Asia: estimates of rates of colonisation, extinction and speciation.
Biol. J. Linnaen Soc. 28: 127-165. Hislop, J. A. 1949. Some field notes on the
bearded pig. Malayan Nature J., 4: 62-64. Hislop, J. A. 1952. More about the bearded
pig. Malayan Nature J., 7: 22-23. Hislop, J. A. 1955. Notes on the migration of
the bearded pig. In: Excavations at Gua Cha, Kelantan, 1954, Appendix E, (ed.
G. de G. Sieveking), Fed. Mus. J. (New Series), 1-2: 134-137. IUCN 1986. IUCN 1986 Red List of Threatened
Animals. IUCN, Gland and Cambridge. Janzen, D. H. 1974. Tropical blackwater
rivers, animals and mast fruiting by the Dipterocarpaceae. Biotropica, 6:
69-103. Jessup, T., Hajani, S., Khumaidi, M. and
Soedjito, H. 1982. Forest for Food - Phase I: Background Report and Proposal
for Research and Development. TAO-Materialen 11, East Kalimantan
Transmigration Area Development Project, Samarinda, Indonesia. Johns, A. D. 1983. Ecological effects of
selective logging in a West Malaysian rain-forest. (Unpubl.) Ph.D. thesis,
University of Cambridge. Kempe, J. E. 1948. The riddle of the bearded
pig. Malayan Nature J., 3: 36-42. Leighton, M. and Leighton, D. R. 1983.
Vertebrate responses to fruiting seasonality within a Bornean rain forest.
In: S. L. Sutton, T. C. Whitmore & A. C. Chadwick (eds.): Tropical Rain
Forest: Ecology and Management, Blackwell, Oxford: 181-196. McGowan, P. 1987. Pigs and Palawan. (Unpubl.)
rep. to the IUCN/SSC Pigs and Peccaries Specialist Group: 4 pp. Medway, Lord 1958. Food bone in Niah Cave
excavations, 1958: a preliminary report. Sarawak Mus. J., 8: 627-636. Medway, Lord 1977. The wild pig remains from
the West Mouth Niah Cave. Sarawak Mus. J. 25: 21-33. Mudar, K. M. 1986. A morphometric analysis of
the five subspecies of Sus barbatus, the bearded pig. (Unpubl.) M.Sc. thesis,
Michigan State University: 86 pp. National Research Council 1983. Little-Known
Asian Animals with a Promising Economic Future. National Academy Press,
Washington, D.C.: 71-74. Oliver, W. L. R. 1992. The taxonomy,
distribution and status of Philippine wild pigs. Silliman J. 36 (1): 55-64. Oliver, W. L. R. and Villamor, C. I. 1993. The
distribution and status of the Calamian deer, Cervus (= Axis) calamianensis, and the Palawan bearded pig, Sus barbatus ahoenobarbus, in the the
Calamian Islands, Palawan Province. (Unpubl.) rep.: 39 pp.. Pfeffer, P. 1959. Biologie et migrations du
sanglier de Borneo (Sus barbatus
Muller, 1869). Mammalia, 23: 277-303. Pfeffer, P. and Caldecott, J. O. 1986. The
bearded pig (Sus barbatus) in East
Kalimantan and Sarawak. J. Malaysian Branch of the Royal Asiatic Soc., 59:
81-100. Quinnell, R. and Balmford, A. 1988. A future
for Palawan's forests ? Oryx, 22 (1): 30-35. Rabor, D. S. 1986. Guide to the Philippine
Flora and Fauna, Vol. XI: Birds, Mammals. Natural Resources Management
Centre, Ministry of Natural Resources and Univ. of the Philippines: 161-164. Shelford, R. W. C. 1916. A naturalist in
Borneo. London. Whitmore, T. C. 1981. Wallace's Line and Plate
Tectonics. Oxford University Press, Oxford. Whitmore, T. C. 1987. Biogeographical
Evolution of the Malay Archipelago. Oxford University Press, Oxford. Whitmore, T. C. 1988. Tropical Rain Forests of
the Far East, 2nd Ed.. Clarendon Press, Oxford. Wilson, E. O. 1975. Sociobiology: the New
Synthesis. Harvard University Press; Cambridge, Massachusetts. |
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Next: Chapter 5.6 – The
Philippine Warty Pigs |