Durrell team in India release nine more endangered pygmy hogs into the wild

Nine captive-bred pygmy hogs have been released into the wild in Manas National Park of Assam, India, by the Pygmy Hog Conservation Programme (PHCP), of which Durrell is a founding partner.

Taking place on Tuesday 1 October 2024, this release brings the number of hogs successfully bred and reintroduced by PHCP across four protected areas of Assam to 179.

PHCP has been working to bring this precious species back from the brink since 1996, with the reintroduction of captive-bred hogs to the wild starting in 2008. The pygmy hog was thought to be extinct until it was rediscovered in the 1970s. It remains under significant threat from the loss of its grassland habitat due to invasive alien plant species, disease, and human disturbance.

“Not only is the pygmy hog one of the most endangered mammals in the world, but it also happens to be an indicator of the health of its habitat,” said Dr. Parag Jyoti Deka, PHCP Project Director at Durrell. “The grassland is home to several other threatened species, including the Bengal florican, hispid hare, and hog deer, and is used extensively by rhinos, elephants, and tigers. If pygmy hogs cannot survive there, you will also start to see the disappearance of these other species too.”

“This project also allows us to address the larger question about the conservation and management of one of India's most biodiversity-rich habitats,” Dr Deka continued. “These wet grasslands help maintain the region's long-term ecological and economic well-being, serving as a buffer against floods during rainy season, and maintaining high groundwater levels in the dry season. Pygmy hog and grassland conservation not only protects other unique and important species, but it also indirectly benefits the communities living around the park.”

Manas National Park contains some of the largest remaining grassland blocks in the sub-Himalayan grassland ecosystems. This was the fifth successful release in the park since 2020, taking the total number of hogs released in Manas to 63.

“The effort for reintroduction and restoring of the endangered pygmy hog in Manas National Park under the Pygmy Hog Conservation Programme is commendable,” stated Shri R. P. Singh, IFS, Principal Chief Conservator of Forest and Head of the Forest Force, Assam, who was present for the release. “I wish the population of the pygmy hog stabilises in this landscape, making Manas more vibrant in its species richness.”

Previous releases took place at Orang National Park, Sonai-Rupai Wildlife Sanctuary, and Barnadi Wildlife Sanctuary. The majority – 59 hogs – were released in Orang, with the current population there estimated to be 130 hogs. The lifespan of a pygmy hog in the wild is around eight years, so this population is likely to be made up entirely of wild-born hogs, which is incredibly exciting for the team.

Extremely shy and secretive animals, pygmy hogs remain hidden in tall dense grass and rarely emerge into the open, which makes monitoring them in the wild a challenge. The team has worked through this by using camera traps and undertaking sign surveys, where they look for pygmy hog pellets, nests, foraging marks, and footprints. In Orang, hogs have been seen up to 2km away from the nearest release site, showing a healthy dispersal and exploration of the site by reintroduced and wild-born individuals.

This year, six of the released hogs were fitted with radio trackers, which will provide critical data about their behaviour and habitat use. A camera trap study from last year’s release site in Manas shows that hogs released in 2023 are exploring and now breeding in the area, and a pregnant female hog was captured on camera in the wild for the first time.

“Maintaining the functionality of grasslands and establishing a stable pygmy hog population requires integrating habitat management with population monitoring,” said Dr. Dhritiman Das, PHCP Field Scientist at Durrell. “Ongoing pygmy hog and habitat monitoring evaluates population trends, ecological dynamics, and reintroduction effectiveness.”

PHCP is made up of founding partners Durrell, Assam Forest Department, the IUCN/SSC Wild Pig Specialist Group, Ministry of Environment and Forests, Government of India, and Ecosystems-India, with Aaranyak as delivery partner. As part of its rewilding strategy, PHCP will continue to maintain a small population of 80 hogs at its two centres in Assam and breed more hogs for release. The strategy for monitoring hogs after their release continues to develop.