ArticlePDF Available
Sus barbatus
Jayasilan Mohd-Azlan1*, Melynda Cheok Ka Yi1, Thaqifah Syaza Jailan1and Yong Min Pui2
1Department of Zoology, Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia
2Institute of Biodiversity and Environmental Conservation, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia
corresponding author email: azlan@unimas.my
The bearded pig (Sus barbatus) is distributed from the Malay Peninsular, Sumatra, Borneo and
the southwestern Philippines (Corbett & Hill, 1992; Oliver, 1995). In Borneo they can be found in
coastal lowlands comprising peat swamp and dipterocarp forest with undulating hills and the
mountain highlands (Payne et al., 1985). The bearded pig is an omnivorous animal that forages
mainly on seeds of Dipterocarpaceae, Fagaceae, fruits, roots and invertebrates (Davis & Payne,
1982; Payne et al., 1985; Caldecott, 1988). This generalist species is known to utilize a wide
variety of habitat types but lives in one location in a stable group for the majority part of the year
(Navennec et al., 2016).
The bearded pig has been reported to be mobile and exhibit a variety of aggregation strategies,
ranging from solitary and sedentary to mass aggregation with wide ranging migration (Meijaard,
2003; Hancock et al., 2006). The shortage of food resources may force pigs to migrate.
Migrations of bearded pig have been reported in Borneo in response to mass fruiting occurrences
in Borneo (Caldecott & Caldecott, 1985; Hancock et al., 2005; Wong et al., 2005). The mast
fruiting events increases population numbers explosively and the pigs are known to migrate
across large areas to feed on the oil rich Dipterocarp seeds (Hancock et al., 2005).
The bearded pig is the most sought after wild meat by the non-Muslim natives in Sarawak where
it plays significant role socioeconomically especially in sustaining local livelihoods. In Sarawak the
bearded pig is not protected outside National Parks, Nature Reserves and Wildlife Sanctuaries.
As a non-protected species, it can be hunted for local consumption. However commercial sale of
bearded pig in Sarawak is prohibited according to Wildlife Protection Ordinance 1998 where
offenders are liable for a fine up to 5000 Ringgit (USD$1250) while the buyers can be fined up to
2000 Ringgit (USD$500). Additionally if a native is found in his possession with more than five
kilograms of wild meat for his own consumption he will be deemed to have the intention to sell or
offer for sale and can be charged up to 5000 Ringgit.
Study site
A rapid survey was carried out in Rajang River area from Kapit town to Pelagus National Park.
Rajang River (also known as Batang Rejang) is the longest river in Malaysia and the largest river
between Sabah and Sarawak, which originates from central highlands of Borneo. The Rajang
headwaters drain the northern slopes of the Kapuas Hulu Range and western slopes of Hose and
Iran mountains while the watershed of Rajang River drains the districts of Kapit, Belaga, Song,
Kanowit, Julau, Sibu, Matu, Daro, Bintangor and Sarikei (Parenti & Lim, 2005). Rajang River
drainage basin is about 50,000 km2in area with elevations exceeding 2,000 m (Parenti & Lim,
2005; Staub & Gastaldo, 2012). From a 30 years rainfall data calculation, the typical single-month
discharge rates for the Rajang River drainage basin range from about 1,000 to 6,000 m3/s, and
the average monthly discharge rate is about 3,600 m3/s (Staub et al., 2000). Peak discharge rates
during the northeast monsoon (December to March) can exceed 25,000 m3/s. There are several
rapids with strong current distributed near the headwaters (Figure 1). This river is used as the
major mode of transportation to the central regions of Sarawak. The river is busy during the
mornings and in the afternoons where express and long boats frequently shuttles people. The
riverbank along this stretch is dominated by secondary lowland dipterocarp forest, patches of
small-scale agricultural farms (e.g. pepper, rubber and paddy rice), settlements (longhouses,
school and abandoned resort), log ponds and a coal mining area. Most of the secondary forests
in this area have been logged several times except for Pelagus National Park which is situated in
the west side of the river.
Rapid boat survey was carried out from 18th – 21st of February 2016 along the Rajang River from
Kapit (N 02˚00’59.4” E 112˚56’25.7”) to Pelagus National Park that stretches approximately 32
km. At any one time there were at least two surveyors in the boat. During this survey we checked
for any bearded pig crossing the Rajang River. We also counted the number of boats and
interviewed local people involved in this hunting activity from the boats (n=20) and elders from the
longhouses (n=15).
The bearded pigs have been reported to cross the river consistently for the past two weeks. This
event occurred for approximately three weeks starting from the beginning of February 2016.
Approximately 50 % of the hunters interviewed suggest that such migrations occur right after the
young piglets were mature enough to swim across rivers for food and this can sometimes last up
to two months. The pigs were crossing from west to east across the river consistently in one
direction especially during early mornings and late evenings when there are fewer boats using the
river. This is consistent with most of the previous river crossings reported by Meijaard (2003).
However it is not known if the pigs have been crossing the river at night. In most cases the pigs
Fig 1. The fast flowing rapids of
Rajang River near the headwaters
close to Pelagus National Park at
Kaki Wong area.
were reported to cross from one to two dozens and occasionally adult females with several
juveniles. These pigs do not appear to be in the stages of emaciation and starvation as reported
by Wong et al. (2005), which suggests that famine or prolonged scarcity of food resources may
not be the driving factor in this migration.
During this rapid survey
we counted appro-
ximately 90 long boats
at any one time at 25 to
30 locations along the
riverbank waiting for
pigs to cross the river
(Figure 2). Each boat
had two to three
individuals looking out
for pigs (Figure 3). This
translates to at least 180
individuals from
approximately 200
villages at any one time
along this 32 km stretch.
Hunting using shotguns
is not allowed. Local
people who are caught
using guns will be asked
by other fellow hunters
from the nearby boats to
leave the area. The pigs
were attacked and killed
using homemade spears
(locally known as
Jerepanq and Sanqkuh:
Figure 4) and machetes.
Once the pigs are
spotted crossing far
enough from the
riverbanks, the boats will
rush towards the pigs
and the first boat to
arrive normally kills at
least one pig at a time. In
general most boats will
hunt at least one pig per
day but boats waiting at
more strategic location
often take two to three
Fig. 2. Location of boats waiting along the Rajang River during the pigs’ migration.
Fig. 3. Longboats with two to three individual waiting near the edge waiting to ambush the migrating
pigs in Rajang River in February 2016.
individuals in a day (Figure 5). The number of
hunters in each boat also partly influences the total
kill per day. A single hunter may only kill and collect
as much as two individuals per day whereas boats
with more hunters will collect as many as they can
fill their boat with. The hunters will wait from
morning until late evening, with their boats parked in
parallel to the pigs’ crossing direction to minimize
the detection of their presence. These hunters are
also opportunistic, as they kill almost all the pig
crossing. As soon as a pig is captured, it is tied to a
big plastic gallon bottle (to keep the pig afloat) while
the hunters move on to the next target and the
process continues until there are no more pigs left
for the session. Occasionally juvenile pigs are
reared if they are captured alive. Excess meat will
be preserved through fermenting and smoking the
meat. During this hunting period, if one hunting
group (per boat) takes home at least one pig per
day, then a modest estimate of pigs harvested
during this migration session at this particular river
stretch in Sarawak for a minimum of 14 days is
estimated at least 1260 pigs. With an approximation
of 30 kilograms of wild meat obtained from each pig
on this basis, this would result in an overall catch
value of 756,000 Ringgit (USD$190,000).
The rapids, wide river crossing, boats and hunting
threats did not prevent the bearded pigs from
crossing the river suggesting that the instinct to
seek new foraging grounds have superseded these
challenges. Preventing the bearded pigs from
migrating
will disable
them to find
alternative food and cause starvation, which in turn may
negatively impact local communities that depend on this
resource. The dependency of pigs on mast fruiting
suggests that the Bornean populations are delicate and
susceptible to continuous local extinctions from human
perturbation (Wong et al., 2005). Therefore local
enforcement agency must work together with local
communities to regulate hunting activities to ensure local
populations of bearded pigs are not exterminated.
Fig. 4. Weapons used for pig hunting during river crossings
(left: Jerepanq, right: Sanqkuh). The spears are about 2 meters
long, with sharp ends. The hunters usually spear the forearms
or hind legs of the pigs, just enough to immobilize them but not
killing them, thus allowing them to stay afloat.
Fig. 5. Juvenile bearded pigs hunted from a long boat
showing spear marks near the neck. Note the lateral black
brown stripes on the abdomen indicating that these
individuals are less than 6 months old.
The authors would like to thank local communities that made this brief study possible. We also
thank Department of Zoology, Faculty of Resource Science and Technology, Universiti Malaysia
Sarawak (UNIMAS), the Institute of Biodiversity and Environmental Conservation for supporting
our research, which funded by the Sarawak Energy (grants no [GL(F07)SEB/2014/03(04)] &
FRGS/STWN10(04)/990/2013(31)). We are grateful to the Sarawak Forestry Department and
Sarawak Forestry Corporation for permission to work in Central Sarawak.
Caldecott, J. O. (1988). Hunting and wildlife management in Sarawak. IUCN, Gland, Switzerland
and Cambridge, UK.
Caldecott, J. O. & Caldecott, S. (1985). A horde of pork. New Scientist, 1469: 32-35.
Corbett, G. B. & Hill, J. E. (1992). The mammals of the Indomalayan region: a systematic review.
Natural History Museum Publications, Oxford University Press.
Davies, G. & Payne, J. B. (1982). A faunal survey of Sabah. WWF Malaysia, Kuala Lumpur.
Gastaldo, R. A. (2010). Peat or no peat: Why do the Rajang and Mahakam Deltas differ?
International Journal of Coal Geology, 83(2): 162-172.
Gastaldo, R. A., Feng, W., & Staub, J. R. (1996). Palynofacies Patterns in Channel Deposits of
the Rajang River and Delta, Sarawak, East Malaysia. PALAIOS, 11(3): 266–279.
http://doi.org/10.2307/3515234
Hancock, P. A., Milner-Gulland, E. J. & Keeling, M. J. (2005). An individual based model of
bearded pig abundance. Ecological Modelling, 181: 123-137.
Hancock, P. A., Milner-Gulland, E. J., & Keeling, M. J. (2006). Modelling the many-wrongs
principle: the navigational advantages of aggregation in nomadic foragers. Journal of
Theoretical Biology, 240(2): 302-310.
Meijaard, E. (2003). Mammals of south-east Asian islands and their late Pleistocene
environments. Journal of Biogeography, 30: 1245-1257.
Navennec, A., Cheok, M. K. Y. & Mohd-Azlan, J. (2016). Analysis on the habitat use of bearded
Pigs in Sarawak. Suiform Soundings: 14(2): 7-12.
Oliver, W. L. (1995). The taxonomy, distribution and status of Philippine wild pigs. Silliman
Journal, 36: 55-64.
Parenti, L. R. & Lim, K. K. P. (2005). Fishes of the Rajang Basin, Sarawak, Malaysia. The Raffles
Bulletin of Zoology, 13: 175-208.
Payne, J., Francis, C. M. & Phillipps, K. (1985). A field guide to the mammals of Borneo. The
Sabah Society.
Staub, J. R. & Gastaldo, R. A. (2012). Late Quaternary sedimentation and peat development in
the Rajang River delta, Sarawak, East Malaysia. Society for Sedimentary Geology, 76: 71-
87.
Staub, J. R., Among, H. L. & Gastaldo, R. A. (2000). Seasonal sediment transport and deposition
in the Rajang River delta, Sarawak, East Malaysia. Sedimentary Geology, 133: 249-264.
Wong, S. T., Servheen, C., Ambu, L. & Norhayati, A. (2005). Impacts of fruit production cycles on
Malayan sun bears and bearded pigs in lowland tropical forest of Sabah, Malaysian
Borneo. Journal of Tropical Ecology, 21: 627-639.
... Additionally, the time commitments related to urban jobs and (e.g. Banks, 1949;Mohd-Azlan et al., 2016). Artwork by Amy Koehler and used with permission KDM community but also the hunting relationship that has connected people and pigs across Borneo for millennia (Medway, 1964). ...
Full-text available
Article
1. Land-use change and political–economic shifts have shaped hunting patterns globally, even as traditional hunting practices endure across many local socio-cultural contexts. The widespread expansion of oil palm cultivation, and associated urbanization, alters land-use patterns, ecological processes, economic relationships, access to land and social practices. 2. In particular, we focus on the socio-ecological dynamics between Kadazandusun-Murut (KDM) hunters in Sabah, Malaysian Borneo, and bearded pigs (Sus barbatus; Malay: ‘babi hutan’), the favoured game animal for non-Muslim communities throughout much of Borneo. We conducted 38 semi-structured interviews spanning over 50 hr with bearded pig hunters, asking them about contemporary hunting practices and motivations, changes in hunting practices, changes in pig behaviour, and patterns of animal protein consumption in village and urban contexts. 3. Amidst widespread land-use change, primarily driven by oil palm expansion, respondents reported substantially different characteristics of hunting in oil palm plantations as compared to hunting in forests. Additionally, 17 of 38 hunters—including 71% (10/14) of hunters who started hunting before 1985, compared to 26% (6/23) of hunters who started hunting in 1985 or later—mentioned that bearded pigs are behaving in a more skittish or fearful way as compared to the past. Our respondents also reported reductions in hunting frequency and wild meat consumption in urban contexts as compared to rural contexts. 4. However, despite these substantial changes in hunting and dietary practices, numerous KDM hunting motivations, hunting techniques and socio-cultural traditions have endured over the last several decades. For some, bearded pig meat remains deeply tied to food provision, gifting and sharing customs, and cultural components of celebrations and feasts. 5. Oil palm has cultivated new hunting practices that differ from those in forests, and has potentially contributed to altered bearded pig behaviour due to increased hunting accessibility. Together, oil palm and urbanization are helping reshape the KDM-bearded pig socio-ecological system. In light of these reshaped connections, we recommend location-specific management approaches that ensure fair access to the dietary and social benefits of bearded pig hunting while preserving the critical conservation needs of bearded pig populations and habitat. These twin goals are particularly urgent given the confirmed outbreak of African Swine Fever (ASF), and mass deaths of domestic pigs and wild bearded pigs, in Sabah and Kalimantan in 2021.
Full-text available
Article
Sanctuary, and a High Conservation Value Forest near Bintulu We used infra-red sensor cameras, a non-invasive method to gather information on bearded pigs over large survey areas and for several months at a time. Total of 32 camera-traps including models from Reconyx and Bushnell were used for 36 locations between March 2012 and November 2013. Occupancy analysis using PRESENCE 2.0 shows that Beach forest and Mixed Dipterocarp Forests are more likely to be inhibited, compared to Kerangas (Heath) forest. Additional sampling and effort is needed to further investigate the habitat preference between protected areas by increasing the number of camera trap locations in different habitats.
Full-text available
Article
The Rajang River and its delta accumulate siliciclastic sediments and dispersed organic matter within river and todal channels as rhythmically stratified sand, silt, and organic drapes. These deposits were vibracored and subsampled, resulting in a data set composed of 84 samples taken from 45 cores. Palynofacies preparations of this sediment facies were examined from throughout the alluvial valley and delta to determine if a single organic matter assemblage characterized these deposits. An underlying assumption of palynofacies analyses in ancient transitional settings is that each lithofacies or depositional environment is characterized by a specific organic matter (OM) assemblage. This specific hypothesis is no supported by the present investigation. However, the present investigation has demonstrated that the resultant dispersed OM assemblages within a single sediment facies is heavily influenced by the geochemistry of the system. Three distinct palynofacies assemblages in this data set have been identified using nonparametric and multivariate statistical analyses. One assemblage, characterized by high amounts of Heterogenous and Homogenous (mainly dammar) Unstructured OM, moderate amounts of Structured OM and Finely Dispersed Unstructured OM, and low amounts of Black Indeterminate OM, is restricted to depositional sites that are principally found in freshwater settings. The second assemblage, characterized by the highest quantities of Heterogenous and Indeterminate Black and the least amount of Finely Dispersed Unstructured OM, is found in channels of the lower delta plain. The distribution of this palynofacies assemblage conforms to the limit of saline influence during the wet season. The third group, characterized by the highest quantitative amount of Finely Dispersed Unstructured OM, is found either in barforms or in black-water tidal channels that are sediment starved. These results indicate that OM assemblages preserved in a single sediment facies characteristic of transitional zones may vary in response to the abiotic processes operating within the system.
Full-text available
Article
We observed a period of famine in the lowland tropical rain forest of Sabah, Malaysia from August 1999 to September 2000. All six Malayan sun bears (Helarctos malayanus) that were captured and radio-collared were in poor physical condition, and two were later found dead. The physical condition of bearded pigs (Sus barbatus) that were captured, observed or photographed by camera traps also revealed that the pigs were in various stages of emaciation and starvation. We surmise that the famine resulted from prolonged scarcity of fruit during an intermast interval in the study area. These phenomena of emaciated animals and fruit scarcity have also been reported from other areas of Borneo. Lowland tropical rain-forest trees of Borneo display supra-annual synchronized general fruiting. We believe that the starvation we observed and the generally low density of large animals in Borneo forests is a consequence of a history of prolonged food scarcity during non-general-fruiting years, but may be accentuated by anthropogenic factors such as forest fragmentation, selective logging, and reduced density of fig trees in logged forests.
Full-text available
Article
The Holocene Rajang River delta plain, which covers an area of 6500 km2, has developed in a tropical, ever-wet climatic setting. Peat deposits, up to 15 m thick, occur in this delta plain. The tributary system to the delta is about 50,000 km2 in area. Elevations exceed 2000 m in the drainage basin and hill slopes are steep. Rainfall in the region exceeds 370 cm/year, with highest rainfall levels or the “wet” season being coincident with the December–March monsoon. The monthly drainage-basin discharge is calculated to average about 3600 m3/s, and the discharge normally ranges from 1000 to 6000 m3/s. Spring tides in coastal areas range from 2.9 to 5.8 m. Tide data indicate that the tides are semidiurnal with a noticeable diurnal inequality. Vibracores recovered from bar forms in tidally influenced distributary channels contain laminated silts and sand-silt couplets that show evidence of rhythmic heterolithic stratification. Grain-size data indicate that these preserved delta plain siliciclastic sediments are the result of estuarine depositional processes that occur during intervals of reduced rainfall or the “dry” season (April–November). The number of laminae preserved per neap–spring cycle is the highest (≅18–20), and the average thickness is the greatest in the middle part of the delta plain. Distributary channels in this region normally contain low-salinity brackish water to freshwater. Vibracores recovered from delta front and prodelta sediments show evidence of heterolithic stratification, but rhythmicity is absent. Grain-size data indicate that preserved delta front and prodelta sediments are implaced by “wet” season processes (December–March) when fluvial flux and delta-plain erosion are at their maxima. Individual silt laminae and/or silt and sand interbeds are sometimes many centimeters thick, but average about 1 cm. These silt laminae and silt and sand interbeds or varves represent annual sedimentation events. These varves demonstrate that about 24 million MT of sediment produced by the drainage basin is deposited in the delta front and prodelta region annually.
Full-text available
Article
Coastal and deltaic Holocene peat accumulations around the equatorial island of Borneo, Southeast Asia, have served as models for economic coal-bearing sequences in the stratigraphic record. Although climatic conditions, vegetational communities, and sedimentary regimes are comparable, peat accumulations are not found on both the western and eastern sides of the island. The Rajang River delta and coastal plain, Sarawak, East Malaysia, are covered in areally extensive, thick peat deposits that have attained at least a thickness of > 13 m in ombrogenous peat domes (Marudi, Baram River). Peat-swamp biomass began to accumulate over Pleistocene podzols when sea level stabilized ∼ 7.5 ka and delta progradation was initiated. The Mahakam River delta and coastal plain, East Kalimantan, Indonesia, also began progradation at this time, but there is no evidence in any part of the coastal region for peat accumulation. Rather, poorly developed organic-rich gleysols occur throughout the delta plain. Both the Rajang River and Mahakam River deltas are tidally influenced, fine-grained systems, with a sediment provenance in the Central Massif. Sediment transported through the Rajang River delta differs in that as much as 60% of the clay minerals deposited in the system are mixed layer (I/S) and expandable (K/E) clays that act to restrict pore water flow in the tidal and overbank deposits that comprise the delta plain. These result in the development of an aquiclude above which paludal conditions develop, promoting accumulation of organic matter. In contrast, there is a low proportion of mixed layer and expandable clays transported in the Mahakam River system. This precludes the development of a stilted water table within the delta, allowing for organic matter recycling without peat accumulation. The presence of a high proportion of expandable clay minerals on the western side of Borneo is a reflection of the weathering and eroding source rocks on this side of the Central Borneo Massif.
Article
Aim The environments that existed in south-east Asian islands during the last glacial are poorly known, limiting our understanding of mammalian biogeography in the region. The objective of this research is to investigate the ecological characteristics of mammal faunas on small islands, and to see whether the habitat requirements of the species in those faunas can be used to deduct the vegetation types that existed on islands before becoming isolated by rising sea levels. Location The maps presented here cover the small islands of tropical south-east Asia, including the Burmese, Thai and Cambodian islands in the north, the islands off the coast of west Sumatra in the west, the islands around Java in the south, and the islands off the east coast of Borneo in the east, including the Philippine islands of Palawan and those in the Sulu Archipelago. Methods The presence records of mammal species on 215 small islands in the region were compiled, and the habitat requirements for each of these species was assessed (species that had probably been introduced by humans were excluded from the analysis). For each island location (longitude and latitude), maximum altitude of the island, total area, depth to nearest land, distance to nearest island, and distance to nearest mainland were assessed. Geographical and statistical analyses were used to investigate patterns of mammalian habitat requirements. Results The geographical analysis showed that forest-dependent species, i.e. species that are only found in primary forest (lowland and mountainous), appear to be concentrated on islands off west Sumatra, in the Lingga and Riau Archipelagos, around Palawan, and around Bunguran Island; they are absent mostly from the islands of the Java Sea, those off the east coast of eastern Borneo, from most islands in the Sunda Strait, several islands in the northern South China Sea, and from all islands off the west coast of the Malay/Thai Peninsula and in the Gulf of Thailand. Species that generally occur outside primary forest, that is those in secondary forest, gardens, plantations and open areas mostly occurred on islands where the forest-dependent species were absent. The statistical analysis showed that latitude and size of islands were important factors that determined the absence and presence of forest-dependent species on small islands. Main conclusions The data suggest that during the last glacial there were several areas in the Sundaic region that remained forest covered: west of Sumatra, north-west of Borneo, the Malacca Straits and around Palawan. Other areas may have been covered by more open vegetation types like tree savanna, or open deciduous forest: on and to the east of the Malay/Thai Peninsula, the Java Sea area, including the Sunda Strait, and eastern Borneo.