Sus barbatus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Cetartiodactyla Suidae

Scientific Name: Sus barbatus Müller, 1838
Infra-specific Taxa Assessed:
Common Name(s):
English Bearded Pig, Western Bearded Pig
French Sanglier À Barbe
Taxonomic Notes: There are two subspecies recognized by Lucchini et al. (2005): oi from Sumatra, Bangka and Palang Bintang in the Riau Archipelago; and barbatus from Peninsular (West) Malaysia, Borneo, and Sibutu Island (west of the Sulu Archipelago). Groves (1981) and Groves and Grubb (1993) previously included ahoenobarbus from Balabac, Palawan and offshore islands and the Calamian Islands, however this has since been classified as a distinct species, S. ahoenobarbus (Groves 2001, Lucchini et al. 2005).

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2cd ver 3.1
Year Published: 2017
Date Assessed: 2016-02-22
Assessor(s): Luskin, M., Ke, A., Meijaard, E., Gumal, M. & Kawanishi, K.
Reviewer(s): Chiozza, F.
Contributor(s): Linkie, M. & Oliver, W.R.T.
Bearded Pig (Sus barbaratus) is assessed as Vulnerable because of a population decline, believed to be more than 30% over the last three generations (taken as 21 years), inferred from over-exploitation, shrinkage in distribution, and habitat destruction and degradation.

Specifically, the Sumatran Bearded Pig (Sus barbatus oi) lost 62% of its potential forest habitat (extent of occurrence) between 1990 and 2010 and its occupied range contracted by 76%. There is likely only one population remaining potentially with >500 individuals, located in Kerinci Seblat National Park. However, Kerinci Seblat continues to experience high rates of habitat loss (>2% per year) and fragmentation (Joshi et al. 2016). Bearded Pigs undergo extreme populations fluctuations as part of the boom-and-bust dynamics associated with regional inter-annual mast fruiting. To persist between masting years, Sus barbatus oi depends on a variety of different habitats (e.g. lowland and montane forest) for temporary resources. The extreme loss and fragmentation of Sumatra lowlands, including Kerinci Seblat, inhibits access to to required habitats. This combination of natural history and threats puts the subspecies at very high danger of extinction in the wild.
The Bornean bearded pig in Peninsular Malaysia lost 33% of its forest habitat (extent of occurrence) and its occupied range contracted by 91% between 1985 and 2010. During the same period, the species lost 23% of its forest habitat (extent of occurrence) and its occupied range contracted by 24% on Borneo. Further, there has been significant fragmentation of remaining habitat in both areas. Due to this nomadic species' large range requirements for tracking seasonal resources, there there are few reaches of connected habitats remaining for their long term persistence. Further, in Borneo, Bearded Pigs are aggressively hunted for meat.
Previously published Red List assessments:

Geographic Range [top]

Range Description:

The two subspecies of Sus barbatus are distinguished by their ranges: S. barbatus oi is native to Sumatra and S. barbatus barbatus is endemic to Peninsular Malaysia, Singapore, and Borneo (including Brunei), as well as Borneo’s near-shore islands (Lucchini et al. 2005). Sus barbatus barbatus is found in the Malay Peninsula and widespread on Borneo (Brunei, Sabah, Sarawak and all Kalimantan states; Oliver, 1995, 2001), while it has been extirpated from Singapore, the Bintan (Riau) Islands (southeast of Singapore), and northern Peninsular Malaysia (the states of Perak, Kelantan, and Selangor, as well as the Karimata and Laut islands off Kalimantan) (Luskin and Ke 2016). Bearded Pigs were recently rediscovered in the isolated area of North Selangor peat swamp reserves but this population is unlikely to persist due to its isolation (Sasidharan et al. 2015). Sus barbatus oi is naturally absent from the northernmost Sumatran province of Aceh, and has been extirpated from North Sumatra and Lampung province (Luskin and Ke 2016).

Countries occurrence:
Brunei Darussalam; Indonesia (Kalimantan, Sumatera); Malaysia (Peninsular Malaysia, Sabah, Sarawak)
Possibly extinct:
Regionally extinct:
Additional data:
Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):UnknownEstimated extent of occurrence (EOO) - km2:1790126
Continuing decline in extent of occurrence (EOO):YesExtreme fluctuations in extent of occurrence (EOO):Yes
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Sus b. barbatus and S. b. oi have experienced marked population declines throughout their range due to extensive habitat loss and fragmentation, and their populations continue to decline (Luskin and Ke 2016). Within Peninsular Malaysia, S. barbatus populations have been reduced dramatically and the Bearded Pig is seriously threatened with extinction there. Bearded Pigs were widely reported from Northern, Southern, and Central Peninsular Malaysia prior to the 1950s (Kawanishi et al. 2013). Remaining populations have been described in the southern state of Johor and eastern state of Pahang, including Endau-Rompin National Park (Lohe 2015). The last confirmed report from other states was in 1996 when a single group of 18 individuals was spotted in the Pasoh Research Forest in the central state of Negiri Sembilan, despite extensive camera trap surveys (Ickes 2003, Kawanishi and Sunquist 2004).

In Borneo S. b. barbatus is heavily hunted and as a result is now extirpated from otherwise suitable lowland forest (Caldecott et al. 1993, Oliver 1992, Bennet et al. 2000, Harrison 2011). In many areas of the highlands in Borneo S. b. barbatus remains locally common in forests > 50 km².

In Sumatra, S. b. oi is at high risk of extinction due to loss of 50% of Sumatra's forested habitat over the last 25 years (Margono et al. 2011), which has severely reduced the range and population sizes of S. b. oi. The last remaining large population (> 500 individuals) is now limited to Kerinci Seblat National Park. There are smaller subpopulations in the remaining lowland fragments of Riau and Jambi, but these face rapid deforestation (e.g. > 30% from 2000-2010; Margono et al. 2011).

Both subspecies of Bearded Pigs are subject to natural drastic population fluctuations due to the mast fruiting phenology of the region.
Current Population Trend:Decreasing
Additional data:
Extreme fluctuations:UnknownPopulation severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:Both subspecies of Bearded Pigs are found in all habitat types within their range (all elevations of forest, as well as peat swamp and mangrove forests) (Caldecott et al. 1993). Both subspecies undergo drastic population fluctuations due to the mast fruiting phenology of the region. In non-mast years, the carrying capacity for Bearded Pigs likely varies greatly between habitat resources (Caldecott et al. 1993).

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 behavior, 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 behavior (Caldecott 1988, Pfeffer 1959, Pfeffer and Caldecott 1986, Davies and Payne 1982, Janzen 1974, Jessup et al. 1982, Leighton and Leighton 1983).

Bearded Pigs practice large-scale nomadic movements to track periodic fruit availability in Borneo (Shelford 1916; Banks 1931, 1949; Banks in Hislop 1955; Pfeffer 1959; Davies and Payne 1982; Caldecott and Caldecott 1985; Caldecott 1988a, 1991), Peninsular Malaysia (Allen 1948; Kempe 1948; Hislop 1949, 1952, 1955), and Sumatra (Boogaarts 1938, Blouch 1984, Linkie and Sadikin 2003). 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 have been 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 travelled 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 Malaysian 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.

Bearded Pig populations exhibit a range of different states, which can be summarized as follows:
  1. 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).
  2. 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).
  3. 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.
  4. 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 Peninsular Malaysia).
  5. 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).
  6. 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 Peninsular Malaysia 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 travelling 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 centred 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.
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):7
Movement patterns:Nomadic
Congregatory:Congregatory (and dispersive)

Use and Trade [top]

Use and Trade: Bearded Pigs are culturally and economically important wildlife to the rural communities in Borneo (Caldecott 1988, Bennett et al. 2001). In particular, its meat is preferred by the local people and therefore it is the most frequently hunted wildlife species (Caldecott 1988, Chin 2001, Bennett et al. 2001). However, hunting is not an issue in Sumatra due to the majority population's Halal diet, and to a lesser degree in Peninsular Malaysia, where only the Chinese (< 40% of the population) consume pig species.

Threats [top]

Major Threat(s): The three primary threats facing Bearded Pigs is the conversion of forests for agriculture, particularly oil palm and rubber, fragmentation of remaining habitat, and unsustainable logging primarily for dipterocarps. A recent analysis shows there are also synergistic effects of climate change and agricultural land use, indicating there may be a substantial increase of oil palm expansion into hill forests within the next few decades (Brodie 2016). The eminent threat of fragmentation hinders Bearded Pigs' ability to track seasonal resources across large areas. In Borneo, fragmentation prevents Bearded Pigs from exhibiting mass population eruptions and long-distance movements of the kind observed during the 1950s and 1980s, which haven't been observed since, even during successive masting events (Hancock et al. 2005). As Bearded Pig populations decline, hunting for meat, once sustainable in many areas, is probably now a serious threat in many places, as evidence by their extirpation from Lambir Hills National Park (Harrison 2011, Harrison et al. 2016).

In Peninsular Malaysia, competition with Eurasian Wild Pigs (Sus scrofa) might also be a significant threat (Kawanishi et al. 2006). Habitat fragmentation favors the sedentary wild boar, and the available data indicate that wherever they are sympatric (not necessarily syntopic), the number of wild boar is greater than Bearded Pigs (Ickes 2001, Ickes and Thomas 2003, Maddox 2007, Luskin et al. 2014).

In Sumatra, habitat loss and fragmentation have been the highest in the world over the last 20 years, putting S. b. oi at direct threat of extinction (Margono et al. 2011, Meitten 2012). The same situation probably applies to Bangka and the Riau Archipelago where the persistence of the species is unclear today.

Repeated complaints about crop depredations by Muslim communities on the Sibutu and Tawitawi Islands in the southwestern Philippines have led to appeals to relevant authorities to try to eradicate these animals, and they may already be extinct there (Oliver 2001). Some earlier concerns that pose that fragmentation of Borneo's forests will allow the wholesale invasion of the island by S. scrofa (which are currently absent from the island) that could then displace S. b. barbatus (Kawanishi et al. 2008) seem to not have played out to date.

Conservation Actions [top]

Conservation Actions: Special management interventions are necessary to protect the species from extinction in Peninsular Malaysia. In Peninsular Malaysia there is no significant protection for the last substantial population that migrates from the eastern coastal forests of southern Pahang to the western coastal forests of Johore, passing though Endau-Rompin National Park in southern Peninsular Malaysia, which is only 891 km². The Bearded Pig is a protected game species under the Protection of Wildlife Act (1972) in Peninsular Malaysia and can be hunted with license with no bag limit for meat or as a measure of pest control. Regulating hunting of Bearded Pigs alone will be difficult, as hunters do not differentiate Bearded Pigs from sympatric wild boars. In Sumatra, Bearded Pigs are known to occur in the large Kerinci-Seblat National Park (Linkie and Sadikin 2003), but this park faces rapid habitat loss and fragmentation. In Borneo, the species is widely distributed and occurs in numerous protected areas in Kalimantan, Sarawak, Sabah and Brunei. It is protected under the Sarawak Wildlife Protection Ordinance, 1998 (Part IV), and specifically in the Trade Ban (Section 33) that prohibits the hunting or selling of wildlife species or wild meat. However, hunting for subsistence in rural areas is still allowed (Chin 2001, Junau et al. 2006).

Bornean Bearded Pigs (S. b. barbatus) of Bornean decent are held in Gladys Porter Zoo, Hellabrunn Zoo, London Zoo, Lowry Park Zoo, National Zoo of Malaysia (Zoo Negara), the San Diego Zoo, Singapore Zoo, Southwick's Zoo, and Zoo Taiping (ISIS 2011). On the contrary, there is only one captive program of S. b. barbatus originating from Peninsular Malaysia, which is at Singapore’s Night Safari Zoo (17 individuals stemming from 4 original captures in Johore). There are no captive populations of S. b. oi.

Due to their interesting physical appearance and prolific reproduction, they are excellent candidates for zoos and captive breeding programs. Captive breeding programs should be immediately initiated for the Sunda/Western Bearded Pig (S. b. oi). Due to the gradient of genetic material ranging from western Sumatra, to the Riau Archipelago, to Peninsular Malaysia, to Borneo, it may be also worthwhile to for breeding programs to capture and retain local and regional genetic distinctiveness. 

Errata [top]

Errata reason: The original version of this assessment was published with an older version of the distribution map. This errata assessment uses the updated distribution map. The Assessor names have also been corrected to include A. Ke as an assessor for this species.

Citation: Luskin, M., Ke, A., Meijaard, E., Gumal, M. & Kawanishi, K. 2017. Sus barbatus (errata version published in 2018). The IUCN Red List of Threatened Species 2017: e.T41772A123793370. . Downloaded on 18 September 2018.
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