Rare piglet born at Chester Zoo as African swine fever pushes species towards extinction

A critically important piglet has been born at Chester Zoo, as conservationists warn her species is being wiped out in the wild by African swine fever.

Little Rana is a babirusa - sometimes called the "pig-deer" - a species found on just four Indonesian islands. Until recently, they were considered vulnerable to extinction by the International Union for the Conservation of Nature (IUCN), but they will shortly be uplisted to Critically Endangered. Since African swine fever reached the islands around five years ago, wild populations have gone into rapid decline, and experts fear the disease could push babirusas towards extinction if action isn't taken.

Rana was the size of a “grapefruit with legs” when she was born - babirusa piglets typically weight between 300 and 500 grams. She's the fifth piglet born to mother Matano, who was herself born at Chester Zoo 11 years ago and now has descendants living in zoos across Europe.

Hannah Owens, Assistant Team Manager at Chester Zoo, said:

“This is the first babirusa birth we've had here for a few years, and Rana is a very special little lady. When she was born, she was tiny - about the size of a grapefruit, with legs. She's grown a lot and is doing really well.

“While babirusas are doing well in our care, I'm worried because they are really struggling in the wild. The numbers are radically reducing, and it would be horrendous if they disappeared, because they are amazing, charismatic animals. Piglets like Rana are a lifeline for the species.”

Babirusa pregnancies are unusually predictable - almost every birth at Chester Zoo has arrived after exactly 161 days of gestation. Keepers began counting down once Matano was seen with male Bamm Bamm early this year, later giving her a quiet, private space and extra bedding to prepare for the birth.

Unlike most pigs, babirusas typically have just one or two piglets at a time rather than large litters - one reason their numbers recover slowly when wild populations are hit hard. New mothers are also highly sensitive to disturbance, so keepers kept an eye on Rana and Matano remotely via a baby monitor until the pair were ready to be seen in public.

Hannah added:

“Babirusas are unique. Their name means 'pig-deer' in Malay, because of their distinctive look. They're much less hairy than other pigs - Rana had ginger fuzz when she was born, but that's gone now. Males are the only pigs whose upper tusks erupt through the snout bone and curve back towards their face.”

Chester Zoo conservationists work with partners to protect wild babirusa populations through the Action Indonesia Global Species Management Plans - helping design camera-trapping projects to monitor babirusas on Sulawesi, working with partner organisations to locate and protect surviving populations, and sharing conservation breeding expertise that has helped Indonesian colleagues breed at least 17 babirusas towards national cooperative breeding targets.

Amy Humphreys, a conservationist at Chester Zoo, is part of Action Indonesia, which is contributing to the Indonesian government’s new plan to save babirusas in the wild.

She witnessed the catastrophic drop in babirusa numbers reflected in a recent camera trap study set up in Sulawesi with Chester Zoo’s support. The study only recorded two instances where babirusas were photographed across the whole of 2023 and 2024.

Amy said: 

“We are in a race against time to understand what’s happening to the population. Babirusas are important to island ecosystems as they drop seeds as they forage, helping forest regeneration, and they are a key indicator species for overall ecosystem health, but their situation is bleak. 

“We risk losing a truly unique species, one that’s an important part of Indonesia’s cultural and natural heritage and one of the oldest pig species still living. Because of all this, Rana’s arrival is worth celebrating. Her birth is a chance to shine a light on babirusas and show people why they deserve protection.”

Babirusa fact file:

Babirusas are omnivorous, and the group at Chester Zoo enjoy buffets of mixed vegetables, mealworms and other proteins, and the occasional peanut.

Both male and female babirusas lack the disc-shaped snout of other pigs, so they can’t root through soil. They are still excellent foragers and will stand onto their back legs to strip fruit from trees.

They are ‘ecological engineers’, spreading and fertilising seeds as they forage. This is important to forest regeneration, as Indonesia is experiencing rapid deforestation.

In addition to ASF, they face risks from habitat loss, hunting and human-wildlife conflict

Babirusa conservation facts:

Chester Zoo is heavily involved in Action Indonesia Day, which has been running since 2019 to raise the awareness of the plight of babirusas and wild cattle species.

The zoo is also involved in the Action Indonesia Global Species Management Programme which monitors babirusas in the wild, coordinates breeding in zoos and sanctuaries, and is pulling together a plan to save babirusas in the wild.

The knowledge Chester Zoo babirusa keepers have developed has been shared with Indonesian zoos and breeding centres.

Chester Zoo experts have helped Indonesian colleagues breed at least 17 babirusas in-country and contribute to the Indonesian National cooperative breeding targets.

More information is available at www.actionindonesiagsmp.org