Sulawesi Warty Pigs are reported to occur in a wide variety of habitats, ranging from rainforest and swamp, to open grasslands and agricultural areas, and at all altitudes up to moss forest (>2,500 m) (MacKinnon 1981), though they are less common at altitudes above 1,500 m asl (Burton et al. 2009). They usually live in groups of from one to six animals, but the social composition of these groups is incompletely known (Macdonald 1991, Macdonald et al. 1996). In Tanjung Peropa Nature Reserve sex ratio of adult was found to be 1:1.25 (n=25), and group size varies between two to nine animals with an average of five individuals (n=16). The group generally was composed of 1-3 young, 1-2 sub adult, and 1-3 adults (Jamaludin et al. 2008).

Sus celebensis is an omnivore, with a wide-ranging diet reported (National Research Council 1983, Mustari 2005). They forage during the day, this activity being concentrated in the early morning and evening. Although roots, fallen fruit, leaves and young shoots constitute the bulk of their diet, invertebrates, small vertebrates and carrion are also eaten (Mustari et al. in prep).

There is little known about reproduction of S. celebensis. A pregnant sow reported from south Sulawesi by Sody (1941) was probably mated in February. Births can occur at any time throughout the year but sows usually have their young in April or May (National Research Council 1983). Gestation length is not known for certain, and the suggestion that it may lie between 16 and 20 weeks should be treated with the caution implied by Sody (1941). Litter size ranges from 2-8 (National research Council 1983), but a recent study in North Sulawesi found six pregnant sows killed by hunters to be carrying only 1-3 fetuses with a mean of only 2.17 fetuses per pregnancy (Budiarso et al. 1991).

Sus celebensis is a medium sized pig which is still found in abundance in central, east and south-east Sulawesi. It is now scarce in south and north-east Sulawesi and may be extinct on nearby Selayar Island. It also occurs as a native form on the adjacent islands of Buton, Muna, Kabeana, Peleng, Lembeh and on some of the Togian Islands (Burton and Macdonald 2006). As originally shown by Groves (1981), this species has also been truly domesticated and widely transported to other islands, where it has also often hybridized with S. scrofa, thus giving rise to a variety of introduced domestic and feral pig populations amongst the Indonesian the islands of Flores, Timor, Simeuleu, Seram, Buru and Nias Islands. Domesticated forms of S. celebensis can be seen on the islands of Roti and Sawu (Groves 1983, Bell 1987). Wild pigs from Halmahera, previously referred to as feral S. celebensis, have been shown to have greater genetic affinity to the New Guinea pigs (Larson et al. 2005).

Sus celebensis is still found in abundance in central, east and south-east Sulawesi. Available evidence suggests that the species formerly occurred throughout Sulawesi, as well as on the neighboring islands of Selayar, Buton, Muna, Kabeana, Peleng, Lembeh and the Togian Islands (MacKinnon 1981, Wiles et al. 2002, Macdonald et al. 2005). By the early 1980s it was reported that this species was greatly reduced in population numbers in south-west Sulawesi, and in nearby Selayar Island, following the virtual deforestation of these areas changed into agriculture and human settlements (MacKinnon 1981, National Research Council 1983).

In 2002, an island wide survey found a pattern of a patchy species distribution throughout Sulawesi Island. There were no records of pigs in three areas in the north east peninsula, and low densities in the central region of the island. Populations in both these regions appear to have been affected by demand for pig meat in Minahasa and Palu areas, respectively (Riley 2002).

The species has also been introduced elsewhere in Indonesia, e.g. to the islands of Flores, Timor, Lendu and Simeulue. The wild pigs on some of these islands are strongly modified and there is now little doubt that S. celebensis has been domesticated, and transported to these areas as a domestic or feral form, probably during the early migrations of peoples. Animals thought to be on S. celebensis origin were reported from the islands of Roti and Sawu (Groves, 1983; Bell, 1987). Hybridized forms of S. celebensis with S. scrofa forms were reported to survive on a number of islands in this region, including Salawatti, Great Kei Island, Dobu, Seram, Ambon, Bacan, Ternate, Morotai and New Guinea (Groves 1981, 1983; Oliver and Brisbin 1993). Genetic information on wild pigs from Halmahera, previously referred to as feral S. celebensis, has shown that they have greater genetic affinity to the New Guinea pigs. mtDNA sequences showed that the New Guinea pigs had haplotypes that clustered with pigs from Halmahera, Hawaii and Vanuwatu and were found in the “Pacific clade” (Larson et al. 2005). This rules out a significant S. celebensis maternal input as previously proposed (Groves 1981). Feral S. celebensis have been reported from Flores, Timor, Lendu and Simeulue and Nias islands (Groves 1981), and this has been confirmed by mtDNA sequences for Flores (Dobney et al. 2008), but for the other islands this now needs to be reassessed.

The species occurs in some protected areas. Those where significant populations of Warty Pigs are found include Lore Lindu (2,310 km²), Bogani Nani-Wartabone (2,871 km²), Morowali (2,250 km²) and many other smaller sites. Within all of these areas the species is technically fully protected by law. A Wildlife Crimes Unit Program was developed for wildlife trade monitoring and law enforcement in North Sulawesi. This has been active since 2001, however, overall trade in wild mammals has increased by 30% during this time, mainly from unprotected species (Lee et al. 2005). This Unit cannot control the levels of trade in the warty pig because hunting of this species is not prohibited outside of protected areas. The species has only very rarely been kept in captivity outside its country of origin; and, as far as is known, pure-bred animals have never been produced in captivity (Burton and Macdonald 2006).