Meet the giant forest hog, which at up to 600 pounds (275 kilograms) brings home the record-setting bacon as the world’s biggest pig.
Despite its imposing size, there’s relatively little known about the African species, a bristly black animal with prominent cheeks and sharp tusks. In fact, the hog was only scientifically described in 1904—making it one of the last big mammals to be identified on the continent.
Enter Rafael Reyna-Hurtado, a National Geographic explorer and wildlife ecologist who’s been studying the seven-foot-long (two-meter-long) beast in Uganda‘s Kibale National Park. Occasionally individuals in other pig species, especially domesticated ones, can grow larger than the giant forest hog, but as a species it’s the biggest overall.
Giant forest hogs live across much of central Africa, though the western population is smaller from the eastern pigs, which are much beefier. (See National Geographic’s best wildlife pictures.)
Reyna-Hurtado, who focuses on the eastern giants, is shedding new light on giant forest hog mysteries, like how far they roam, what they eat, how they interact with each other, and most of all, how they’ve managed to live such a secretive existence.
“It’s an amazing species, and very few people see them given that they are a relatively large animal,” said Reyna-Hurtado, of El Colegio de la Frontera Sur, a research center in Mexico.
Yet giant forest hogs haven’t managed to avoid us entirely. People are hunting the pig for food more than ever before, and the East African populations have been “decreasing at alarming rates” over the past three decades, according to Reyna—making studying them more crucial than ever.
“We can’t afford to lose this species,” he said.
Big and Beautiful
There are 18 wild pig species living today around the world, from the pygmy hog to the wild boar, but most remain poorly studied. For instance, very few scientists have looked at the giant forest hog, and most of that research was done in the 1970s to 1990s and published in French and German.
“The reasons for that are unclear, but maybe pigs are not considered cool enough,” Erik Meijaard, chair of the International Union for Conservation of Nature’s Pig Specialist Group, said by email.
“Of course, we entirely disagree. Wild pigs are not just beautiful, they are very important ecosystem engineers, and a major source of wild protein to many communities in Asia and Africa.”
For instance, giant forest hogs keep disperse plant species, and their activities often redistribute and aerate soil.
They’re also crafty. Despite tracking a group of giant forest hogs on two expeditions, Reyna never got close enough to dart an animal so he could put a radio collar on it—the animals were always a step ahead, during one occasion making agitated, hippo-like snorts and grunts. (Watch “How to Catch a Hog” on the National Geographic Channel.)
However, Reyna and colleague Alex Tumukunde, a Ugandan Ph.D. student, made some meaningful observations about the animals. For instance, they mapped a giant forest hog’s home range, which averages about 3.8 square miles (10 square kilometers).
The team also found that Ugandan giant forest hogs prefer living in areas with both dense thickets and open areas with sparse trees. The animals eat grasses in the clearings and rest in the refuge of the brush, where they clear the ground of leaves and sleep on the bare ground—”beds” that they’ll return to repeatedly.
Previous research has shown that the hogs use a well-worn network of trails that connect their grazing meadows, water holes, wallows, salt licks, and more, and that the pigs even use “communal latrines,” forming dung heaps along the trails, according to the Handbook of the Mammals of the World, Vol. 2.
Thanks in part to remote-triggered camera traps, the scientists noted that groups consisted of between 8 to 12 animals, including a dominant male and a female with piglets. (See the best camera-trap pictures of 2012.)
Snares were more of an unwelcome discovery. The scientists came across traps set by hunters, and a local patrol discovered 59 snares in just four days—set to capture not only forest hogs but other species such as bushbuck, according to Reyna.
Before the era of camera traps and GPS collars, he was “good ol’ Crocodile Dundee running around the savanna, looking with binoculars at groups of giant forest hogs,” said d’Huart, now head of the Belgium-based Conservation Consultancy Services.
Over time some of the hogs mostly tolerated his presence, but “at times, they can be very dangerous animals, as females would charge to protect their piglets and males will attack people to defend their families,” he said.
“Once or twice I was the victim of a charge. Wounds can be very nasty—when they really want to hurt you, they open the mouth and inflict wounds with their lower tusks, [which are] extremely sharp, like a knife.”
During his research, d’Huart became fascinated by the animals because of their ability to adjust their diet and lifestyle to meet whatever conditions they find themselves in.
For example, not only can the hogs thrive in a variety of habitats, but they are also omnivores, munching on everything from grass to bark to worms to fruits to insects to eggs, he said. (Piglets are reportedly fond of fresh elephant dung.)
What’s more, the hogs can switch their sleeping schedules if the need arises—for instance, night-active giant forest hogs in the Congo’s North Kivu region became daytime dwellers when Virunga National Park was protected from hunters, d’Huart said.
This extreme adaptability “may also explain why a species [that's] not very difficult to trap and hunt has not disappeared … They always find a way of surviving.”
That is, to a point—severe, nonstop hunting could locally wipe out some populations, d’Huart cautioned.
One problem is that hunters can easily figure out the pigs’ well-established trails, which crisscross relatively small areas.
Since most of the pigs are hunted locally for food, they’re not part of the illegal wildlife trade, Reyna-Hurtado noted. One solution may be to inform local people that the giant forest hog is on the decline in Uganda, and work with them to find other sources of protein, such as chicken.
“We need to develop economic alternatives that allow people to raise animals for meat without depending on wildlife,” Reyna-Hurtado said.
Overall, Meijaard noted, Reyna-Hurtado’s work “provides valuable insights” for predicting future populations of giant forest hogs, as well as what people should do to save them.
“It would be a real tragedy if the species or significant populations of the species became extinct.”