World's tiniest pig, once thought extinct, returning to the wild

The shy, 10-inch-tall pygmy hog, "rediscovered" in 1971, is steadily increasing in number due to captive breeding in its native India.

By Kamakshi Ayyar
Published 27 May 2021, 10:04 BST

A critically endangered pygmy hog, Porcula salvania, at the Pygmy Hog Breeding Centre in Guwahati.

Photograph by Joël Sartore, Nat Geo Image Collection

In the thick, tall grasslands of the Himalaya foothills lives the endangered pygmy hog, a species so small its piglets can fit in your pocket. Standing about 10 inches tall, the shy animal once roamed the border regions of India, Nepal, and Bhutan, snuffling about for insects and tubers. 

But a century of habitat degradation and destruction—especially conversion of grasslands for agriculture use—devastated the pygmy hog, and until its “rediscovery” in 1971, many people thought the animal was likely extinct.

In the mid-1990s, conservationists captured some wild pigs and began breeding them in captivity, releasing them back into Assam, a state in northeastern India where a tiny wild population had survived. 

Twenty-five years later, these conservation efforts are paying off, experts say: Altogether, between 300 and 400 animals remain in the wild, and 76 in captivity, and the species appears to be thriving.

The success of the initial program has led to subsequent efforts. Between 2008 and 2020, scientists released 130 pygmy hogs into two national parks, Manas and Orang, and two wildlife sanctuaries, Barnadi and Sonai Rupai—all in Assam.

There are plans to release at least 60 more pigs into Manas within the next five years, says Parag Deka, project director of the Pygmy Hog Conservation Programme, based in Guwahati, Assam’s capital.

“It’s very important for me to keep going and save this species from extinction,” Deka says. “We should all look for a purpose in life. When I got involved in this project, I realised this can give me that purpose.”

A special pig

Seventeen species of wild pig live around the world, and almost all of them are endangered. But what makes the pygmy hog so special (other than its diminutive size) is its evolutionary uniqueness: It’s the only species from the genus Porcula, says Matthew Linkie, Asia coordinator for the International Union for Conservation of Nature’s Wild Pig Specialist Group.

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If we were to lose this species,” he says, “then we’d lose an entire genus and millions of years of its evolution in an instant.”

The conservation program is giving the species “more than a fighting chance for survival,” adds Linkie, who commended the team’s recent efforts to protect captive pygmy hog populations from diseases such as African swine fever, a viral disease that appeared in the region in 2020 along with COVID-19. (Learn how scientists are working to predict the next pandemic.)

The pygmy hog conservationists implemented strict biosecurity measures for the staff, vehicles, and equipment entering the breeding area, he says.

“While the [African swine fever] virus has a high economic impact on the domestic swine industry, for pygmy hogs and other threatened species, it can mean the tip towards extinction,” says Johanna Rode-Margono, chair of the IUCN Wild Pig Specialist Group.

“The teams on site do everything they can to protect the captive and the wild populations.”


First described by western science in 1847, the pygmy hog was rarely seen over the ensuing century, due to its size and skittishness. In his 1964 book The Wild Life of India, naturalist Edward Pritchard Gee wrote he was “trying hard to find out if [the pygmy hog] still exists.”

As a result, details about its lifestyle and behaviour were lacking: Adult pygmy hogs, which weigh between 6 and 9 kg, rely on grasslands as protection from predators, such as pythons and crows, as well as a safe space to forage and collect building material. (Read about the world’s biggest pig, the giant forest hog.)

The pigs tear down the grass to build thatched roofs for their nests, which are created over depressions in the ground. A pygmy hog family usually consists of three to five individuals, a combination of females and young; boars usually only join for a few months during the mating season.

In 1971, long after its last-known sighting, a tea garden labourer caught a group of pygmy hogs fleeing a prescribed fire near Barnadi sanctuary (a type of protected area) in Assam. Shortly after that, a tea estate manager named Richard Graves bought 12 pigs from the labourer at a local market.

 Graves’ boss, John Yandel, informed naturalist Gerald Durrell, founder of the Durrell Wildlife Conservation Trust, about the find. Trust scientists came to Assam to research the hogs, but it took another two decades to launch the Pygmy Hog Conservation Programme, which began capturing wild hogs to breed in 1996.

When captive-bred piglets reach about six months old, they’re moved to an outdoor pre-release centre in Potasali, near Nameri National Park. For another six months or so, the youngsters explore and adapt to the recreated grassland habitat. After their release, the pigs are monitored via camera traps, radio transmitters, and on-the-ground surveys.

Green desert

Breeding pigs is only part of the solution: They also need healthy grasslands . When assessing potential release sites, the team looks for alluvial soil (earth full of mineral deposits brought by rivers), certain species of native grass and plants, and up to about two square miles of habitat.

But it’s tough to find such areas: Assam’s grasslands are dwindling, degrading, and fragmented. Barnadi, the sanctuary where the pigs were found in 1971, has shrunk from about four square miles of grassland to less than half a square mile. 

In the past, illegal and indiscriminate burning of grasslands to create open spaces and fresh fodder for cattle threatened the hogs, especially during the pigs’ mating and breeding seasons. Constant burning also encourages weeds—which thrive in disturbed environments—to grow and displace native grasses.

 “It looks very green, but I call it the green desert, because nothing can grow there,” Deka says.

That’s why the conservation team is working with local communities and forest officials to understand how to reduce such pressures on the grasslands and develop better habitat management practices.

 “When we’re out patrolling, we cut down species like Siam weed and red cotton trees, that threaten the grasslands,” says Arjun Kumar Rabha, a forest guard at Manas National Park, who has worked with the pygmy hog conservationists for six years. “Earlier, grassland burning wasn’t monitored because of socio-political unrest in the region. Now we practice controlled burning.”

The team also encourages creating fire lines between blocks of grasslands to ensure that blazes don’t spread and taking a break for a few weeks between burnings, allowing new vegetation to grow in other areas to which that the pigs and other grassland-dependent species can migrate.

The goal is to restore at least 11 square miles of grasslands in Manas National Park by 2025, Deka says. Eventually, the pigs should repopulate the land and thrive, he says.


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