19 May 2023

Incredible new research started by our scientists and an international team has uncovered a new pig species. Introducing… the Bawean warty pig!

Little is known about this elusive and unique species, which is found only on the tiny island of Bawean in the Java Sea, Indonesia, but it’s thought to be one of the most threatened pigs in the world.Bawean warty pig

Two juvenile Bawean warty pigs captured fighting on a camera trap. Photo credit: Association for Nature and Biodiversity – ANB

They’re the only pigs found on Bawean but they were previously thought to be the more common Javan warty pig, despite looking quite different. However, innovative genetic analysis has now revealed that the DNA of these animals is very distinct, and that the two are much less genetically similar than scientists once thought.

In fact, the research team estimated that these rare pigs diverged from their closest living relatives on Java at least 166,000 years ago!


One of the conservationists involved in the discovery, our very own Dr Stuart Young, Regional Field Programme Manager Southeast Asian Islands at Chester Zoo, said:

Stu Young


“We’ve discovered that the Bawean warty pig could now be the most threatened species of pig in the world, with only an estimated 234–467 mature individuals remaining. Our research and the identification of this new species is key as it will help to prioritise urgent conservation action for them on Bawean. It’s vital that we do all we possibly can to protect this species as they are a key part of the island’s ecosystem and their extinction would likely have wider knock-on effects to both the biodiversity and people on Bawean.”

A species worth protecting

Pigs around the world are often called ‘ecosystem engineers’ as they change their environments in a hugely positive way and play a key part in supporting healthy ecosystems, such as by turning over soil, creating microhabitats, and acting as important prey species. Sadly, many are threatened by habitat loss, hunting, conflicts over crops, being killed for entertainment, and diseases like the fatal African Swine Fever.


As Bawean is a small island, the research team predicts that it likely never supported large numbers of warty pigs. Worryingly though, their genetic analysis suggests that the Bawean warty pigs showed signs of a recent decline in numbers and a low diversity in their genes, meaning they’re more at risk to things like diseases and environmental change. While the conservation status of the Bawean warty pig is yet to be officially assessed by the IUCN, with less than 500 on the island, it’s likely to be Critically Endangered.

Bawean island is also the only place in the world where you can find the Bawean deer (Axis kuhlii), serpent eagle (Spilornis baweanus) and freshwater crab (Parathelphusa baweanensis), but the addition of the Bawean warty pig adds to the incredible richness of biodiversity supported there. However, unlike the charismatic endemic Bawean deer, Bawean warty pigs are not yet legally protected and are occasionally hunted in retaliation for eating farmers’ crops, which represents one of the main threats to its future survival.

Bawean warty pigMale Bawean warty pig with characteristic facial warts captured by a camera trap. Photo credit: Association for Nature and Biodiversity – ANB

The research team suggest that urgent legal protection and conservation action is needed to ensure this species can survive in the long-term.

Already we’re working with our partners to look at ways of preventing crop raiding in other pig species that could also be applied to help work towards achieving coexistence between people and Bawean warty pigs. We hope this important work can support the communities on the island while helping to change the perceptions of this species from a pest to something worth protecting.