John Hendrix knows what it’s like to fight an uphill battle against an invasive species.
“About eight years ago, these hogs started showing up,” said Hendrix, a farmer who lives in the Taylors Bridge community of Sampson County in southeastern North Carolina. “And they were rooting up fields of corn ... Last year, I lost five acres in one field, and my neighbor lost probably 10 acres in one field.”
Feral swine — also known as wild hogs, razorbacks, or Russian boar — cause upwards of $2.5 billion in damages across the United States each year. In Sampson County, frequent hog sightings and significant crop damage have prompted federal and local government groups to launch a new pilot project to tackle the problem in the area.
When a group of hogs feasts on a field of corn or other crop they leave destruction in their wake. One of their signature moves is rooting — planting their snouts in the soil and digging around for insects, tubers, roots, anything that could possibly be food. You might not catch the clever hogs in action, but you can nearly always tell where they’ve been.
More than 6 million feral hogs roam the country today, mostly concentrated in the Southern and Western U.S. A well-fed feral hog can weigh up to 300 pounds, and in some rare cases, hogs as large as 800 pounds have been reported in the South. In addition to rooting, the invasive species uproot and eat commercial crops, consume local wildlife, spread disease, prompt erosion, contaminate local water sources, and new research shows they contribute to carbon emissions.
Feral hogs are descendants of pigs imported by Spanish explorers in the 1500s, Eurasian boar imported in the 1900s, escaped domestic pigs, and a mix between these varieties.
In North Carolina, the number of feral swine is hard to pin down because the data collection here is quite new, according to Falyn Owens, extension wildlife biologist with the state Wildlife Resources Commission.
“We're still just coming up with sort of a first view of where we have swine,” said Owens. “But I can say that it's very likely that we have feral swine in every county in North Carolina.”
Sampson County is now the testing grounds for the new eradication effort. The county counts more domestic swine than people, and ranks second in the nation for pork production. Feral swine can spread diseases like brucellosis to domestic hogs, putting livestock operations at high risk. The region’s rich soil and flat landscape also make it some of the best farmland in the state.
In the most recent USDA Farm Bill, $2.6 million in grant funding was directed to the project, including $1.37 for Sampson County and $1.25 million for a Five County Feral Swine Trap Grant.
Earlier this summer, about 100 or so farmers and landowners shuffled into the Sampson County Livestock Arena for the launch of the Sampson County Pilot Project and to find out more about the beasts that are tearing up their crop rows and evading their traps and rifles.
A significant part of the effort is to build trust between landowners, farmers and government groups. Hendrix, the farmer and landowner, spoke at the event. After documenting the swine damage on his land, he wanted other farmers to understand what’s at stake if feral hogs were to spread a disease like African swine flu to the commercial hog herds.
“That's the thing that worries me,” said Hendrix. “Our little church would suffer if our church members lose their farm. And school teachers — if their husbands can’t farm anymore — it’s going to hurt. And this has the potential for that.”
The ultimate goals of the pilot project are to encourage farmers to track and report feral swine damage, implement eradication tools like remote-control-triggered traps on their land, and help farmers get rid of the carcasses of feral swine that they shoot.
Despite having access to the latest trap technology, experts like state USDA Director Steve Smith say no one tool is foolproof.
“There is not a single type of trap that we've used historically or today that we've never had an escape from,” said Smith as he assisted with an outdoor trap demonstration at the town hall. “They'll bust through. Even as hard as these welds are, they have busted through this before. They'll jump. It's incredible how high they can jump.”
Wild hog sport hunting is a popular activity in the Southern U.S., but experts emphasize that the practice won’t help eradicate the pigs in the long run.
“We know how to protect animals that we want to continue to be able to hunt,” said Owens, the wildlife biologist. “That can boil down to, you know, letting young animals go, letting females go, and targeting older male animals which are the trophy animals. So if you are really focusing on hunting your adult male animals, and not removing females or young, that will allow the population to grow.”
Over generations farmers have bred domestic pigs — some of the shared ancestors of wild hogs — to be fast growers and prolific breeders. When they escape into the wild, domestic pigs can weaponize those traits. Wildlife officials have labeled the exponential growth of their populations aferal swine bomb.
“A three-month-old sow can be capable of reproducing. And they can have multiple litters per year, and we're talking about potentially a dozen piglets or more per litter, so they can multiply very rapidly,” said Owens.
Within months, a domestic pig that’s released into the wild can become well adapted to life outside a pen. Within a few generations, they can transform, changing shape and showing off their sharp tusks — essentially developing the tools to thrive in their new habitat.
New research published in the journal Global Change Biology indicates that the rapidly expanding spread of feral hogs in the U.S. and abroad brings another significant complication — carbon emissions.
“Feral hogs are what we call ecosystem engineers: they disturb the soil, they move the earth, they change ecosystems,” says Christopher O'Bryan, a postdoctoral research fellow in the School of Earth and Environmental Sciences at the University of Queensland who contributed to the research.
A team led by scientists at the University of Queensland and the University of Canterbury found that wild pigs are releasing about 4.9 million metric tonnes of carbon dioxide annually across the globe — the equivalent of the emissions from 1.1 million cars. They do this by rooting up the soil.
“When feral hogs, or humans for that matter, disturb the soil, they're exposing that soil to oxygen. And when that soil is exposed to oxygen, it promotes the rapid development and reproduction of microbes in the soil,” said O’Bryan. “These microbes break down the organic material contained in the soil and that causes the carbon in the soil to be exposed to oxygen as well. And that can create carbon emissions.”
About three times more carbon is stored in the soil than in the atmosphere, says O’Bryan. If feral hogs continue their rapid spread across the U.S. and beyond, the potential for exponential carbon emissions increases.
On top of the carbon contributions, when feral hogs disturb the soil they also create a wave of other ecological changes.
“These effects can be in the form of erosion, ecosystem destruction that affects sensitive species such as plant species, amphibians, reptiles, small mammals that are susceptible to any sort of soil damage.”
As wild hogs continue to make their deep mark on natural and farmed spaces across the Southern U.S., government groups are hoping concerted efforts like the Sampson County Pilot Project will offer insights into how to reduce their populations.
Owens, the wildlife biologist, recognizes there will be obstacles along the way, but she maintains hope that feral hogs in N.C. may one day be rooted out.
“There's always the possibility of a new influx of maybe domestic swine escaping that could end up creating new small pockets,” she said. “But on a large scale, as our technology improves on capturing these animals, I think for all practical purposes eradication is an achievable goal in the long term.”
Want to learn more about feral and other species? CREEP is a podcast about creatures invading our space, and changing the world around us, presented by WUNC and the North Carolina Museum of Natural Sciences. Listen and subscribe wherever you get your podcasts.
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