|Scientific Name:||Sus barbatus|
|Species Authority:||Müller, 1838|
|Taxonomic Notes:||Three subspecies were recognized by Groves (1981) and Groves and Grubb (1993): oi from Peninsular (West) Malaysia, Sumatra, Bangka and Palang Bintang in the Riau Archipelago; barbatus from Borneo and Sibutu Island, west of the Sulu Archipelago); and ahoenobarbus from Balabac, Palawan and offshore islands and the Calamian Islands. However the latter has since been assigned to a distinct species, S. ahoenobarbus (Groves 2001, Lucchini et al. 2005).|
|Red List Category & Criteria:||Vulnerable A2cd ver 3.1|
|Assessor(s):||Kawanishi, K., Gumal, M. & Oliver, W.|
|Reviewer(s):||Leus, K. & Oliver, W. ( Pig, Peccary & Hippo Red List Authority)|
Listed as Vulnerable because of a population decline, estimated 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.
|Range Description:||The Bearded Pig is found in the Malay Peninsula, Sumatra, Bangka (where its continued presence is uncertain), and Borneo (Brunei, Sabah, Sarawak and Kalimantan), extending to Siibuto and Tawitawi Islands in the Sulu Archipelago, in the extreme southwestern Philippines (Oliver, 1995, 2001). There are also records from Bintan (Riau) Islands (southeast of Singapore), where it might be extirpated, and from Karimata and Laut Islands off Kalimantan. The species has probably been extirpated from northern Peninsular Malaysia and northern Sumatra, but it is still present in parts of its historical range, such as the western Sumatran mountain areas (Linkie and Sadikin 2003, Sugardjito pers. comm.) and southern Peninsular Malaysia. The species is apparently most widespread on Borneo, which might hold the bulk of the population.
The Bearded pig was fairly abundant and widespread in the Malaysian Peninsula until relatively recently (Caldecott et al. 1993). As late as 1990, herds of bearded pigs were reported in central Peninsular Malaysia at Taman Negara National Park (Khadijah 1990) and in a forest reserve south of Taman Negara (Johns 1983). But between 1999 and 2001 an intensive camera-trapping study of three sites covering 600 km² of the park did not record the presence of the species (Kawanishi and Sunquist 2004). Elsewhere in 1996, a herd consisting of about 18 Bearded pigs, was seen in a forest reserve in Negri Sembilan in the southwestern peninsula (Kalan Ickes pers. comm., Ickes and Thomas 2003). In a peat swamp forest of southeastern Peninsular Malaysia, the species was reported present by local indigenous people (Sebastian 1998, Wetland International 2003) but a subsequent field survey (Traeholt and Lim 1999) and a camera-trapping study (Sharma and Ahmad Zafir 2005) did not to confirm the presence. At the turn of the 21st Century there were reports of bearded pigs still existing in southern Peninsular Malaysia (Kawanishi et al. 2006), including sightings in 2007 and 2008. Photographs as well as video recordings also exist of the species in Endau Rompin National Park (Song Horng pers. comm.).
In Sumatra, the Bearded Pig has been recorded in west Sumatra (Linkie and Sadikin 2003) in central Sumatra (Maddox 2007a) and in south Sumatra (Maddox et al. 2007b).
Native:Brunei Darussalam; Indonesia (Kalimantan, Sumatera); Malaysia (Peninsular Malaysia, Sabah, Sarawak); Philippines
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species has usually been considered to be locally common wthin its range, though it is heavily hunted and declining (Caldecott et al. 1993, Oliver 1992). However, of all the populations of Bearded Pig, only the Bornean one seems still to be relatively healthy (Kawanishi et al. 2006). The species has declined seriously in Peninsular Malaysia over the last fifteen years, having diappeared from many former sights, and it is certainly no longer common there. Declines are also evident in Sumatra, though the timing of these is less clear. Overall, the species is clearly decreasing.|
|Habitat and Ecology:||
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 (Caldecott et al., 1993). 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 (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 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 Malaysia (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 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 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.
Bearded pigs are culturally and economically important wildlife to the rural communities in Borneo (Caldecott 1988). Its meat is preferred by the local people and therefore it is the most frequently hunted wildlife species (Caldecott 1988, Chin 2001). Improved access into the forests and destruction of their natural habitats by logging and agricultural activities have increased hunting pressure on the Bearded pigs. Moreover, habitat degradation through logging of dipterocarps is believed to reduce the availability of food and the loss of habitat for foraging and breeding, although little is known about the pig's diet and habitat use in response to logging (Setyawati et al. 2005). Evidence is mounting that the bearded pig is dependent on the survival of extensive areas of tropical forest, but these are in serious decline, especially due to expanding plantations (notably oil palm), fires and logging.
The unsustainable logging of dipterocarps in Bornean forests is changing 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 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 Peninsular Malaysia, where several thousands of square kilometres 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. "Classic" bearded pig eruptions with maximum reproduction and population growth appear to be linked to consecutive and large mass fruit crops over an extended time period (Hancock et al. 2005). These consecutive mass fruit crops are thought to be compromised in the future not only by the loss of extensive and contiguous forest cover, but also by climate change (Hancock et al. 2005).
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 favoured S. scrofa over S. barbatus, and the latter species is believed to be in serious jeopardy as a result. Although habitat loss and disruption have almost certainly contributed to the bearded pig's rarity in Peninsular Malaysia, competition with Eurasian wild pigs might also be a significant factor (Kawanishi et al. 2006). Available data indicate that wherever they are sympatric (not necessarily syntopic), the number of Eurasian wild pigs is greater than bearded pigs (Ickes 2001, Ickes and Thomas 2003, Maddox 2007). Both in Peninsular Malaysia and Sumatra, the Eurasian wild pig has a much greater distribution range than the bearded pig.
In Sumatra, 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, and where the continued survival of the species is not clear.
As bearded pig populations decline, the impact of hunting for meat, once probably sustainable in many areas, is becoming much more serious, and hunting is probably now a serious threat in many places.
Repeated complaints about crop depredations by Moslem communities in communities in Sibutu and Tawitawi Islands in southwestern Philippines have not only led to appeals to the relevant authorities to try to eradicate these animals, but also to the discovery of a new (if as yet unpublished) description of a wild pig species endemic to Tawitawi and offshore islands (Oliver 2001; Rose and Grubb, unpublished), though it remains unclear whether S. barbatus occurs sympatrically or is replaced by these animals on these islands.
In Peninsular Malaysia, the Taman Negara National Park , 4,343 km², may be the only protected area large enough to support a viable population, if the species is still present. Bearded pigs are found in Endau-Rompin National Park in southern Peninsular Malaysia. Although the park is only 891 km², there are plans for intensive field conservation in the protected area and surrounding logged-over forests, thus increasing the potential of long-term prevalence of this species here. In Sumatra, Bearded pigs are known to occur in the large Kerinci-Seblat National Park (Linkie and Sadikin 2003), 13,300 km², and they are likely to survive in some other protected areas, though surveys are needed to confirm this. In Borneo, the species is widely distributed and it occurs in numerous protected areas in Kalimantan, Sarawak, Sabah and Brunei.
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. If, as it appears, the Bearded pig distribution is limited to southern Peninsular Malaysia, special management interventions are necessary to protect the species from extinction in Peninsular Malaysia. Regulating hunting of Bearded pigs alone will be difficult as hunters do not differentiate Bearded pigs from sympatric wild pigs. A study to determine the status and distribution of the species is necessary first to clearly identify what further actions may be required. Its marginal occurrence in the Philippines, where it is undoubtedly seriously threatened by virtue of its extremely limited distribution and active persecution, is unquestioned, but not yet reflected in local legislature.
The Bearded pig is protected under the Sarawak Wildlife Protection Ordinance, 1998 (Part IV of the Ordinance - Protection of Wildlife) specifically 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).
The only apparent captive population of Peninsular Malaysian Bearded pigs seems to be the herd of 7 males and 10 females at Singapore's Night Safari. There are two captive herds of Bearded pig in Peninsular Malaysia, 8 individuals at Zoo Taiping and 14 at Zoo Negara in Kuala Lumpur (Lazarus and Ngah pers. comm.) but these two herds are all of Bornean origin. The Singapore animals stem from three wild importations totaling 2 males and 2 females in 1991 from Johor. Should further research indicate that a limited reintroduction of captive-bred animals was deemed appropriate as part of a broader conservation plan, the Singapore stock could provide animals for release (Kawanishi et al. 2006).
|Citation:||Kawanishi, K., Gumal, M. & Oliver, W. 2008. Sus barbatus. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 25 October 2014.|