By day, they rest in the surviving scraps of rainforest on their remote tropical-island home. By night, they grub around for tubers and roots in the forest gardens of local communities, dodging guard dogs and the occasional angry farmer with a gun.
Now, the diminutive warty pigs of Bawean, a small island in Indonesia’s Java Sea, have a new claim to fame: they may be the rarest pigs in the world.
The warty pigs of Southeast Asia come in many shapes and sizes – and, it seems, many species too. Often dismissed as little more than pests, they are receiving a taxonomic makeover, with a dozen distinct species now acknowledged, and others likely to emerge.
The latest is the Bawean warty pig (Sus blouchi), a dwarf relative of the Javan warty pig (Sus verrucosus), but now claimed to be a species in its own right.
It is smaller than its cousin and has three scent lobes on the back of its front legs rather than the four found on the Javan pig, says its chief champion, Dutch researcher Mark Rademaker of the VHL University of Applied Sciences in Leeuwarden, the Netherlands.
Rademaker published the first ever ecological study of the animal this week, based on records from 100 camera traps scattered across its tiny home – a volcanic island just 15 kilometres across. He estimates the pig’s population to number about 230 individuals.
Much of the centre of Bawean Island was declared protected in the 1930s. But it is far from clear that this has helped the warty pigs, which find most of their food by foraging for roots and tubers among the forest gardens of local villagers.
“Community forests appear to be very important to the pigs. They prefer semi-open cultivated habitat,” says Rademaker. The small size of the island suggests that the pig’s numbers may never have been much higher than today, he says.
Nonetheless, he says that the animal, which currently has no protection under Indonesian law, qualifies for endangered status at the International Union for Conservation of Nature, where Rademaker is a member of the wild-pig specialist group.
But the warty pigs may not be cute enough to bring many TV camera crews rushing to Bawean. “The males have three pairs of enormous warts on each side of their face,” says Johanna Rode-Margono, a wild-pig specialist from the North of England Zoological Society in the UK.
The pigs are part of an unlikely menagerie of endemic species on the island, which has been separated from neighbouring islands for 10,000 years. Others include a critically endangered deer, a subspecies of crested serpent eagle thought to be down to its last 30 pairs, and a spotted wood owl.
Rademaker and Rode-Margono have set up a conservation project, the Bawean Endemics Conservation Initative, to document and protect the island’s rarities.
Journal reference: PLOS One, DOI: 10.1371/journal.pone.0151732