The use of tools is often related to primates and birds. But it was discovered a few years ago that a pig, the Visayan Warty Hog, uses sticks and bark for digging, and rocks to test electric fences. It’s the only pig in the world where interaction with tools has been scientifically documented.

The biggal

The Visayan warty pig Sus cebifrons is also called the Cebu bearded pig, baboy ilahas, baboy do mor, baboy talunon, manggalisak banban, biggal, and bakatin. For the rest of this essay, we’ll refer to the Visayas warty pig as biggal. 

In a zoo in Paris, Meredith Root-Bernstein noted in 2015 that the biggal employs a stick or bark for digging their nests, along with their snout. Root-Bernstein observed this use of tools by the biggal in 2015 at the ménagerie du Jardin des Plantes Paris, which translates to the Zoo in the Botanical Garden of Paris. She saw a biggal use a piece of bark for digging.   

With each successive visit, Root-Bernstein saw the same piece of bark in different positions, but always next to the nest pit that it created. Within two years, the nest was filled with two piglets and their parents.

She tried to find information about pigs using tools, but there was nothing on record. Because of this, she and her research team wrote a paper about how the biggal uses tools in nest building. To see the biggal doing so, go here. 

In the course of writing this paper, other behaviors were observed, such as the Visayan warty hog’s “Michael Jackson moonwalk” which it did to drag dirt, leaves, and mulch into a mound surrounding its nest. 

Although some zoos provide nests for these biggals, the mama sow will add more leaves and sticks, then blanket her young in bedding by day, (the biggal is nocturnal) and tucking them into the pile before climbing in herself to sleep.  

The Root-Bernstein paper, called Context-specific Tool Use by Meredith Root-Bernstein, Trupthi Narayan, Lucile Cornier, and Aude Bourgeois is the first structured observation of unprompted instrumental object manipulation in a pig. They focused on two adult females and one adult male. The females used bark or sticks to move soil using a rowing motion, while the male used the stick for digging. 

For Root-Bernstein, many questions remain: Namely, why bother with a tool if a snout is just as efficient? The most likely answer is that there isn’t a clear functional explanation, much like chimpanzees that hold hands during grooming so that the groomer has only one hand free.

“Learned things and cultural things work that way,” Root-Bernstein says. “Maybe,” she adds, “it just feels like the right thing to do.”

Sadly, we have yet to find a scientific study about the observation by Fernando “Dino” Gutierrez, president of the Philippine conservation nonprofit Talarak Foundation, Inc, who saw biggals pushing rocks toward an electric fence. He told National Geographic by email, “As soon as they push and the rocks make contact (with the electric fence), they would wait for the clicking sound or absence thereof.” A click meant the wires are hot, causing the biggals to back away. If there was no sound, the biggals knew they could safely cross the wire and see what lies beyond. 

Such rare behavior in swine opens the door to new possibilities for tool use and social learning in Suidae, the family of the biggals. Hopefully, a plan will be made to ensure that the critically endangered biggal will grow in number to a safe population, and there will be sufficient, safe nature parks where they can be rewilded, considering that the biggal is the first swine animal that was observed interacting with tools and testing the safety of its environment using rocks.

Female biggals build nests in hidden areas such as between the buttresses (elevated roots) of giant trees that are surrounded by dense bushes. On average, a litter will consist of up to five piglets at most, but there have been cases where eight piglets comprised a single litter. These piglets are exceptionally cute with brown, tan, and black horizontal stripes on their bodies. As they grow these stripes will disappear and the sows will have a white stripe above their noses down to their necks, while the boars will have tusks and sometimes mohawks that cover their eyes like Willebrant, an anime character from the manga series.


Biggals are called “Visayan warty pigs” due to three pairs of fleshy “warts” on the cheeks of adult males. Tony Vecchio, executive director of the Jacksonville Zoo and Gardens in Florida, said these warts are like a pad under their skin. The warts are possibly there to protect the faces of the males during tusk fights. 

The critically endangered biggal is relatively small with a head and body length of 3.2 feet, and a shoulder height of one to two feet.  It’s usually lean but with captivity, can become obese weighing from 77 to 176 pounds as adults. The male is larger than the female. 

The sow has dark hair, and its body is sparsely covered with spiky hair. Male hair is light brown to silver. The adult males have a clump of hair between their ears. On Panay island, their hair will grow and turn into a long mane running from their head to their tail. Sometimes the clumps of hair hang over its face. 

The biggal has a long face and a round nasal disc, but the female biggal is easily recognized by the white stripe which runs over the bridge of its nose, and behind its mouth. This quality is less noticed in male biggals. However, the latter are distinct for their tusks. The biggal is only found in the Philippine Visayan islands, particularly Panay island and Negros island. 

Males are territorial, and they actively defend their territory against other herds of pigs or predators. They can swim very well. They are omnivores, feeding mainly on fruits, leaves, and invertebrates. Due to human activity and the loss of natural habitats, they also look for food in areas where palm trees, avocados, or taro grow.

Social behavior

Little is known about the biggal’s behavior in the wild, as their habitat is continually being destroyed, leaving a decreasingly smaller space for them. To preserve them conservationists must rescue them in the wild so they can be raised and bred in captivity for eventual rewilding in a safe nature park.

What’s known of the feral biggal is that in the wild they live in social groups called sounders. One adult male is the leader, followed by a few sows, and up to multiple generations of offspring. 

Single male biggals will live together in bachelor groups but sometimes a second adult boar will join a sounder and try to mate with a sow, then move on to find another sow to mate with as well.  

Sounders have three to twelve members. The sounders and other social groups of biggals forage for food on the ground seeking worms, mushrooms, and yams. Their sense of smell is strong and their snout can powerfully dig into the ground.

They also eat tubers, insects, and fruits that have fallen from a tree and are too big for birds to eat. They have become the bane of farmers because they also eat their crops like cereal and vegetables.

Communication among sounder members is constant, emitting chirrups, grunts, squeaks, and short, high-pitched sounds. The male pigs are territorial, but sometimes their home ranges overlap and they share food and water. Pigs don’t sweat, so they also share wallowing areas and muddy areas where they can roll in the water or mud to cool themselves. Perhaps it’s a habit of giving and taking. These nocturnal creatures will also sometimes wait until twilight before they start moving around, then they’ll rest in the hollows of trees for the remainder of the day.

Behavior in captivity

According to animal keepers, the biggal sows are very social. They groom one another, scratch themselves against the trunks of trees, and then lie in the sun. They learn quickly and are master  foragers. They love rooting, digging their keen snouts into the ground for the scent of food, then using their forelimbs and back limbs for digging. 

In zoos overseas, biggals display special activity in the early spring. They’re even great climbers with their powerful limbs. At the Woodland Park Zoo, they’re fed yams, carrots, romaine, alfalfa pellets, and spinach—but their favorite treats are peanuts and mealworms. Biggals can live from 10 to 15 years.

It’s possible to domesticate a Biggal. A man in Palawan purchased the animal as a piglet, and raised, fed, and caressed it lovingly until adulthood. The pig is friendly to the man and his family including little children, but not to strangers, so they tie the pig when strangers come around. A vet who visited the animal tried to inject some vitamins into it, but its skin was so tough that it broke two needles, forcing the vet to use a third, stronger needle.


There was a time when the biggal thrived on Panay, Guimaras, Negros, Cebu, Masbate, and perhaps Ticao Islands. It’s endemic to Western Visayas (particularly Negros and Panay), which is situated in the central Philippines. 

It’s unknown whether the biggal formerly lived on nearby Siquijor island, where wild pigs were decimated. The species was replaced by the Philippine warty pig on Bohol and all other larger Philippine Islands east of Palawan and Borneo. Today, most of the biggal’s range is wiped out, and only fragmented populations have survived on Negros and Panay.

The biggal was possibly annihilated from three to four of the six islands where it may have formerly lived. In Cebu, the last biggal was reportedly seen in the 1960s. It is no longer found in Guimaras and Ticao Islands, and it’s possibly “functionally extinct” in Masbate, where the last individuals were confirmed to be seen in 1993. They were few in number and only occupied one location, making them vulnerable to extinction.

 At one time, the biggal lived in primary and secondary forests from sea level to mossy forest grounds at an elevation of 1,600 meters. Now it occurs mostly above 800 meters elevations. There are a few patches of suitable habitat in the lowlands. 

The biggal can survive in some degraded habitats that are filled with cogon grasslands and areas of dense cover. Evidence also exists that pigs are surviving in largely denuded areas, but they’re predominately feral animals of mixed origin.

Only a few populations in forest fragments on Negros and Panay Islands are potentially viable. They, as in the past, face the added danger of hybridization of free-ranging domestic or feral pigs with the wild biggal, which has oftentimes led to genetic contamination.  

The interbreeding of domestic or feral (once domesticated but escaped and lives in the wild) pigs with the wild biggal (which has never been domesticated) has led the Philippine government to establish rescue and breeding centers to help preserve these beautiful animals.


Possibly less than 200 biggals remain in the wild. The decline in their number was caused by human expansion,  conversion of forest lands to farm lands, and forest logging of their valuable hardwoods in the 1970s and ‘80s in West Visayas. Today 95% of the biggal’s natural range is gone. The biggals’ shrinking population was aggravated by rogue hunting that disrespects the boundaries of national parks, and hybridization with domestic pigs. 

As of 2019, some 300 biggals exist in captivity, while their population in the wild is unknown. However, biggals breed well in captivity, and zoos and other facilities worldwide are raising them for eventual rewilding

Hope for the biggal 

Fernando “Dino” Gutierrez, president of the Philippine conservation nonprofit Talarak Foundation, Inc. told National Geographic, “The pigs are actually doing better as compared to 20 years ago. If left alone, they’re definitely going to bounce back.” 

The biggal does well under captive breeding. It reaches sexual maturity within 2-3 years, when the male grows an attractive nine-inch-long, coarse, floppy mane that, depending on your generation, is comparable to Elvis Presley, Michael Jackson, or Willebrant, an anime character from the manga series.

There have been cases when a biggal could breed much earlier at 12-14 months. When the mother gives birth to her young, they’ll depend on her milk for six months, but after one month they can start to eat food as well as drink their mother’s milk.  

One litter can be three to six piglets that will live from 10 to 15 years. This gives hope that biggals can be rewilded if well cared for in captivity. Some conservation zoos also care for these perfectly precious pigs, such as Woodland Park Zoo in Seattle, USA, which has three of them, a mother (14 years old) and her two daughters (8 years old), NewQuay Zoo, UK,  Chester Zoo, UK, and Oregon Zoo, US. 

What if there were no biggals

The biggal in the wild aerates the soil whenever it forages for food. In this way, it makes many nutrients available in the soil. By adding air, many microorganisms can release plant nutrients into the soil. It also maintains a necessary balance between soil air and soil water. Without proper aeration, soil air will be displaced by the soil water.

In other ways, biggals play a major role in regenerating the forest. When they eat fallen fruits that are too large for birds to eat, they later disperse the seeds of the fruit around the forest through its waste. They also distribute the seeds of tubers in the same way. 

Pigs also like to engage in rooting, using their snouts to push or nudge the ground repeatedly. They do this for self-comfort, to cool off, and as a way of communicating. This rooting behavior aerates the soil  even more, contributing in a large part to the well-being of its ecosystem.

As of now, we must make sure that we don’t lose the biggal, not just for its benefits to the ecosystem, but for the potential to study it and learn. The only pig in the world that uses tools is the biggal, and it moves stones against poles to see if they are electric fences. Hopefully, we will learn all that the biggal can teach us through the opportunity to observe them first in captivity, and later in the wild.