The taxonomy, distribution and status of Philippine Wild pigs

Abstract

Recent studies have revealed that there are three species and at least two subspecies of wild pigs in the Philippines, of which two species and one subspecies are endemic. This is a larger number of endemic suid taxa than any other country, with the exception of Indonesia. Within the country, the distribution of the native and endemic suids follows broadly predictable lines, with divisions equating to the major “faunal regions” of late Pleistoceneislands. Thus the “warty” pigs east of Wallace’s Line in Luzon and Mindanao (including Samar, Leyte and, probably,Bohol), i.e. S. philippensis, and those of the West-central Visayas Islands (Panay, Negros, Cebu and, probably,Masbate), i.e. S. cebifrons, are endemic at the species level; whereas those of Palawan and associated islands, i.e. S.b. ahoenobarbus, are closely related to the “bearded” pigs of the Sundaic Region (Borneo, Sumatra, MalaysianPeninsular, etc.) and are endemic only at the subspecies level. There is also evidence that the range of the nominate form of the bearded pig from Borneo, i.e.S. b. barbatus, extends to the small islands of Tawitawi and Sibutu in the Sulu Archipelago. If this is the case, these are the only non-endemic wild pig populations in the Philippines. Unfortunately, however, the generally extreme levels of deforestation on most islands on which they occur, coupled with intense hunting pressure, inadequate legal protection and the poor enforcement of existing legislation even within most protected areas, have resulted in the systematic decline of all Philippine populations of these animals. These factors are especially apparent in the (west) Visayan region, where the endemic warty pig, S. cebifrons, is already extinct or close to extinction on at least four (Masbate, Guimaras, Cebu and Sequijor) of the six islands in which it is known or believed to have occurred. It now survives only in a few small, isolated areas on Negros and Panay, where all remaining populations are declining as a result of continued habitat destruction and intense hunting pressure. These populations are also potentially seriously threatened by “genetic contamination” through interbreedingwith free-ranging domestic and feral pigs (unpubl. data). By comparison, S.philippensisremains relativelywidely distributed in most still-forested areas on the larger islands of Luzon, Samar, Leyte and Mindanao, where it occurs in all of the principal national parks. It probably also still occurs on a number of the smaller islands within these regions, but is certainly threatened or extinct on some others. Further studies are likely to reveal genetic differences between some of the principal populations of this species, which is currently (but probably incorrectly) regardedas monotypic.