Sus celebensis, Muller & Schlegel, 1843

Don E. Wilson & Russell A. Mittermeier, 2011, Suidae, Handbook of the Mammals of the World – Volume 2 Hoofed Mammals, Barcelona: Lynx Edicions, pp. 248-291 : 286-287

14.

Sulawesi Warty Pig

Sus celebensis

French: Sanglier des Célébes / German: Sulawesi-Pustelschwein / Spanish: Jabali de Célebes

Taxonomy. Sus celebensis Muller & Schlegel, 1843 ,

Manado, Celebes.

Genetic studies have suggested that S. celebensis forms two clades, one restricted to northern Sulawesi and the other to the remainder of the species’ range. This can be explained either by the occurrence of two colonization events onto Sulawesi or the historic fragmentation of the island into at least two parts. Taxonomic differ-entiation between the two clades is not sufficiently supported by morphological studies, although the average skull size of S. celebensis was found to be considerably greater for southern Sulawesi than for northern Sulawesi. Provisionally monotypic.

Distribution. Sulawesi and adjacent Is (Buton, Kabaena, Muna, Peleng, Lembeh, and on some of the Togian Is); thought to be extinct on Selayar I. Pigs have been widely domesticated through the Indonesian archipelago and beyond. This primarily involved the Eurasian Wild Pig (S. scrofa ), but also S. celebensis , the only other species of pig successfully domesticated. Mitochondrial DNA studies of the dispersion of these domesticated forms agree on three major dispersal events, two involving S. scrofa and one S. celebensis . Evidence supports an early human-mediated translocation of S. celebensis to Flores and Timor and two later, separate human-mediated dispersals of domestic pig through islands of SE Asia into Oceania. In addition to Flores and Timor, S. celebensis is also thought to occur in its domesticated form on Halmahera, Lendu, Roti, and Savur Is, and even on Simeulue and Nias Is to the W of Sumatra and far from its island of origin, Sulawesi. In the Moluccas, and possibly elsewhere in this region, introduced S. celebensis are thought to have hybridized with other introduced pigs of S. scrofa derivation, and apparent hybrids between these species are now reported to survive on a number of islands, including Salawatti, Great Kei, Dobu, Seram, Ambon, Bacan, Ternate, Morotai, and New Guinea. It is also reported that in the 19" century the sows of domestic pigs in Sulawesi frequently mated with wild animals, after which they returned to their villages.

Descriptive notes. Head—body 80-130 cm, tail 25-35 cm, shoulder height 70 cm; weight 40-70 kg. Adult animals are usually dark-haired, although some individuals are reddish-brown or yellowish in color, sometimes with lighter colored hairs on the trunk and abdomen. There is always a dark dorsal stripe, and a clear yellow snout band is usually present. A short mane and distinct crest of longer hair on the crown or forehead has been recorded for captive animals, but observations on 27 animals in the wild in north Sulawesi found no instances of a crest as long as in the zoo specimens. This might be because, as in the Visayan Warty Pig (S. cebifrons) and the Philippine Warty Pig (S. philippensis), prominent manes and crests may only occur during the breeding season (in the case of these latter species, from late November to April). It is unclear when the wild observations on S. celebensis were made. Young are born with five dark brown and six pale horizontalstripes along the length of their bodies, which they lose at an age of about six months. Adult males have three pairs of facial warts, the preorbital pair being the largest, the infraorbital somewhat smaller, and the mandibular warts emerging from a whorl of hair that first marks their position; the warts enlarge and eventually dominate (at least in captive specimens). The legs are relatively very short, and the back is short and slightly convex. Thetail is long and simply tufted. Adult males are larger than sows, averaging 70 cm at the shoulder in males as opposed to 60 cm in females. Recent forms are larger than the subfossil remains found in caves in southern Sulawesi. S. celebensis has a chromosome number of 38. There are significant differences in the banding of the Y chromosome of S. celebensis , however, when compared with either S. scrofa or the Javan Warty Pig (S. verrucosus).

Habitat. This species is reported to occur in a wide variety of habitats, including rainforests, swamps, high grassland terrains, and agricultural areas. It is found at elevations up to moss forest at about 2300 m, but it prefers valleys.

Food and Feeding. Little is known about the feeding behavior of S. celebensis . Roots, fallen fruit, leaves, and young shoots are thought to constitute the bulk of their diet, with invertebrates, small vertebrates, and carrion as occasional secondary additions. However, no quantitative data are available about percentages of these itemsin their diets, and how this varies over time and in different habitats. Unlike babirusas, S. celebensis has been observed to consume grasses, although this is based on brief observations only.

Breeding. Mating is reported to occur in February, although this is based on only one observation. Births can occur at any time throughout the year but sows usually have their young in April or May. Gestation length is not known for certain, and the suggestion that it may be between 16 and 20 weeks should be treated with caution. Farrowing sows give birth in nests made of grasses, leaves, branches, and twigs piled over a shallow excavation approximately 2 m in length. Litter size has been estimated as 2-8 piglets, with an average offive, although a study in North Sulawesi in 1991 found six pregnant sows killed by hunters to be carrying only 1-3 fetuses, with a mean of only 2-17 fetuses per pregnancy.

Activity patterns. The Sulawesi Warty Pig is primarily diurnal. Most feeding activity observed in relatively undisturbed areas occurs during the daylight hours, concentrated in the early morning and late afternoon.

Movements, Home range and Social organization. Few data exist on group size, but observations around a salt lick recorded single animals (five times), pairs (two times), groups of three (four times), and one group of six. In another population the sex ratio of adults was found to be 1:1-25 (n = 25) and group size was 2-9, with an average of five (n = 16). Groups generally consisted of 1-3 young, 1-2 subadults, and 1-3 adults. These and observations from the 19" century suggest that the species occurs in small troops or families. Densities ranged from 0-4-2 ind/km? in a reserve on the north peninsula to 1:8-19-8 ind/km? and 5-1-14-5 ind/km? in two reserves on the south-east peninsula. A recent study in those reserves found even higher densities in lowland forest (23-5 ind/km?). Such major differences in density are thought to result from varying hunting pressure, with Muslim-dominated areas, where people do not eat pigs, having higher population densities than areas where Christians predominate. With inter-island trade being common, however,it is unclear to what extent Muslimdominated areas become suppliers to the Christian ones. Also, in the south-east peninsula, which is mostly Muslim, S. celebensis has apparently been extirpated, so obviously religious affinity is not sufficient to prevent local extinction of the species.

Status and Conservation. Classified as Near Threatened on The IUCN Red List based on the level of the main threats, habitat loss and hunting. S. celebensis is a species of the central and eastern islands of Indonesia, occurring east of Wallace's Line, which separates the faunas and floras with Oriental affiliation in the west from the Australasian ones in the east. Generally the species is considered to be common, although statements along these lines have been repeated for decades without actual field surveys providing supporting information. S. celebensis has a patchy distribution on most of Sulawesi Island; it is most common in the south-eastern parts of the island. The species has been considered scarce in south-west Sulawesi for over two decades because of ongoing deforestation and hunting. Decreasing sign of pigs in various parts of southern Sulawesi was noted as early as 1938. Extensive logging and conversion of land for agriculture, coupled with human population expansion and immigration, have resulted in the marked contraction and fragmentation ofits range in most places. Market surveys also indicate that the species is under high hunting pressure. For example, brief surveys of three village markets in north-eastern Sulawesi concluded that about 2-20 wild pigs per week were being sold by commercial hunters and slaughtered by butchers when needed. Wild piglets that are caught by villagers in Sulawesi are kept and usually raised for slaughter for eating or sold at the local market. The high volume of trade in this species raises concerns about the sustainability of the current harvesting rate. The fact that the species is not protected outside certain protected areas, and can therefore be openly hunted and traded, makesit difficult to reduce consumption to more sustainable levels. Surveys within protected areas also show that the species is commonly hunted there, and in three protected areas in north Sulawesi no sign at all was found of S. celebensis . It is clear that there are few if any areas where the species can be considered secure. S. celebensis is of particular interest in that it is the only pig species, apart from S. scrofa that has been domesticated and quite widely transported by human agency outsideits original range. The available evidence indicates that it is still maintained as a domestic in some areas, but its commercial importance and future potential as a genetic resource are unknown.

Bibliography. Alvard (2000), Bosma et al. (1991), Budiarso (1991), Burton (2002), Burton & Macdonald (20086, 2008), Clason (1976), Clayton & Milner-Gulland (2000), Clayton et al. (1997), Dobney et al. (2008), Groves (1981), Hooijer (1969), Huffman (1999), Keeling et al. (1999), Larson, Cucchi et al. (2007), Larson, Dobney et al. (2005), Lee et al. (2005), Macdonald (1991b, 1993), Macdonald et al. (1996), Milner-Gulland & Clayton (2002), Nehring (1889), O'Brien & Kinnaird (1996), Riley (2002), von Rosenberg (1865), Toxopeus (1938), Wiles et al. (2002).

Figures

On following pages 10 Phılıppıne Warty Pıg (Sus phı/ıppensıs) Mındoro Wany Png (Sus olıven) 12 Pılawın Bearded Pıg (Sus ıhoanobırbus). 13 Bearded Psg (Sus barbatus), 14 Sulawesı Wany Pug (Sus celebensıs) 15 Javan Wany Pıg (Sus venucosusl. 16 Eurasıan Wıld Pıg (Sus scrola) 17 Pygmy Hog (Porcııla salvımı)

Distribution. Sulawesi and adjacent Is (Buton, Kabaena, Muna, Peleng, Lembeh, and on some of the Togian Is); thought to be extinct on Selayar I. Pigs have been widely domesticated through the Indonesian archipelago and beyond. This primarily involved the Eurasian Wild Pig (S. scrofa ), but also S. celebensis , the only other species of pig successfully domesticated. Mitochondrial DNA studies of the dispersion of these domesticated forms agree on three major dispersal events, two involving S. scrofa and one S. celebensis . Evidence supports an early human-mediated translocation of S. celebensis to Flores and Timor and two later, separate human-mediated dispersals of domestic pig through islands of SE Asia into Oceania. In addition to Flores and Timor, S. celebensis is also thought to occur in its domesticated form on Halmahera, Lendu, Roti, and Savur Is, and even on Simeulue and Nias Is to the W of Sumatra and far from its island of origin, Sulawesi. In the Moluccas , and possibly elsewhere in this region, introduced S. celebensis are thought to have hybridized with other introduced pigs of S. scrofa derivation, and apparent hybrids between these species are now reported to survive on a number of islands, including Salawatti, Great Kei, Dobu, Seram, Ambon , Bacan, Ternate , Morotai, and New Guinea . It is also reported that in the 19" century the sows of domestic pigs in Sulawesi frequently mated with wild animals, after which they returned to their villages.