News Release

Fewer than 250 mature Bawean warty pigs in existence

Indonesian pig species is nocturnal, prefers foraging in energy-rich, community-owned forests

Peer-Reviewed Publication


Bawean Warty Pigs

image: Female and male Bawean warty pig -- image from camera trap. view more 

Credit: Bawean Endemics Conservation Initiative, BEKI

The rare Bawean warty pig mostly forages at night in community-owned forests on Bawean island, and is endangered, according to a study published April 6, 2016 in the open-access journal PLOS ONE by Mark Rademaker from the VHL University of Applied Sciences, The Netherlands, and colleagues.

The Bawean warty pig is found solely on Bawean island, Indonesia. Previously, only anecdotal information existed about the Bawean warty pig's behavior and conservation needs, gathered mostly from examining museum specimens and interviews with local people. To better understand this species, the authors of this study recorded footage of wild Bawean warty pigs over three months using camera traps at over 100 locations to estimate the species' population size, as well as to assess its activity patterns and preferred habitat types.

According to the findings, the Bawean warty pig has a low population density compared to other pig species in Southeast Asia, with a total population of fewer than 250 mature individuals. This, along with its very limited range, suggests it should have at least an IUCN/SSC Red List status of Endangered. The authors also report that the pigs were mainly nocturnal and preferred to forage in community-owned forests and near forest borders, the former likely to contain energy-rich foods for the pigs, such as roots and tubers. This habitat preference makes them vulnerable to conflict with local communities.

Co-author Johanna Rode-Margono notes, "While females look very similar to wild boar the male Bawean warty pigs has three pairs of enormous warts on each side of its face. Only less than 250 mature animals occur on the island of Bawean, making them one of the rarest pig species on earth."

Further research is needed, but this systematic study of the Bawean warty pig may provide valuable initial information about its ecology and conservation needs.


In your coverage please use this URL to provide access to the freely available paper:

Citation: Rademaker M, Meijaard E, Semiadi G, Blokland S, Neilson EW, Rode-Margono EJ (2016) First ecological study of the Bawean warty pig (Sus blouchi), one of the rarest pigs on earth. PLoS ONE 11(4): e0151732. doi:10.1371/journal.pone.0151732

Funding: This work was funded with the generous contribution of the Peoples Trust for Endangered Species (, Die Zoologische Gesellsaft fur Arten- und Populationschutz (, the Los Angeles Zoo and Botanical Gardens ( and Stiftung Artenschutz ( The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests: The authors have read the journal's policy and the authors of this manuscript have the following competing interests: Mark Rademaker Competing interest: Professional Member IUCN/SSC Wild Pig Specialist Group. Erik Meijaard Competing interest: Professional Chair IUCN/SSC Wild Pig Specialist Group. Gono Semiadi Competing interest: Professional Member IUCN/SSC Wild Pig Specialist Group, Member Indonesian Institute of Sciences. Johanna Rode-Margono Competing interest: Professional Member IUCN/SSC Wild Pig Specialist Group. There are no patents, products in development or marketed products to declare. This does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials.

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