The babirusa is known only from Sulawesi (B. b. celebensis), some of the Togian Islands (B. b. togeanensis), the Sula Islands and Buru (B. b. babyrussa). Two extinct forms, one fossil and one recent (B. b. bolabatuensis), have been found in South Sulawesi. The species is therefore presumed to have been more widely distributed on Sulawesi in earlier times, but by the middle of the last century they were reported to occur only in the east and north-east parts of the island and to have disappeared from the whole of the south-western peninsula. Currently, babirusa are known only from the northern peninsula, central and south-eastern parts of the Sulawesi mainland, and from three of the larger Togian Islands Archipelago. Reports obtained in 1990 indicate that babirusa also survive on Buru and two of the Sula islands, Mangole and Taliabu, but that they may now be extinct on Sulabesi (formerly Sanana). However, there is no doubt but that babirusa are seriously threatened over most of their remaining range by deforestation and hunting pressure; the latter being particularly intense in parts of northern Sulawesi where there is commercial trade in the meat of these animals (Blouch, 1990; Budiarso et al., 1991).
Much of the available information on the natural history and biology of this species is anecdotal or derived from the study of captive specimens. Distribution and status surveys in all parts of its range are required as a matter of high priority, with a view to the development of management plans for its enhanced future protection and the establishment of additional reserves in key areas, such as Buru, Mangole and the Togians. The possibility of relic populations of B. b. bolabatuensis surviving in remote locations in south Sulawesi should be investigated, and the taxonomic relationships of the central and south-eastern Sulawesi populations, which are unknown at present, need to be assessed. The first longer-term field study of the species' behaviour and ecology has been initiated recently in northern Sulawesi, and such studies should be continued and extended to other parts of the species' range in the near future. Particular emphasis should be placed on obtaining a proper understanding of its habitat preferences, population sizes and densities in different habitats, and the nature and extent of factors, such as hunting pressure, deforestation and agricultural encroachment, which are negatively influencing the distribution and numbers of surviving populations. Although there are large numbers of B. b. celebensis being maintained and bred in zoological collections at present, the captive population is extremely inbred. Priority should therefore be given to the acquisition of additional, wild-caught founders of this subspecies, and to the development of properly structured breeding programmes for the more threatened Togian subspecies, B. b. togeanensis, and, especially, the golden or hairy subspecies, B. b. babyrussa
