Can we stop invasive species by eating them?

Standing in the kitchen of Dai Due restaurant in the US city of Austin, the strong smell of cooking pork hitting my nose, I'm worried. I'm vegan for environmental reasons and pork was the first meat I stopped eating — more than a decade ago. But here I was, about to try some.  

Though I'm apprehensive,I know the meat I'm going to eat isn't just any old pork. It's from a feral hog, which is one of the most destructive invasive animals in the United States. And because they wreak so much havoc on the environment, they're widely considered to be better off dead than alive. That means it's open hunting season in Texas all year round, with an invitation from the authorities to kill as many as possible. 

Dai Due co-owner and chef Jesse Griffiths, who prioritizes local ingredients and sustainability at the restaurant, often features feral hogs on his menu.  He is among those who sees killing them as an environmental necessity and describes them as an "inarguable source of protein.” 

"If it came down to just one meat that I was forced to say is the best one for us to consume, I wouldn't even pause. It's this one, right here.” 

With no predators in Texas, feral hogs roam free causing extensive environmental damageImage: Larry Ditto/Avalon/IMAGO

What are feral hogs and what is the problem with them? 

Feral hogs are not native to the United States but are the product of inter-breeding between domesticated pigs originally brought over by European colonizers and wild boar. Because they reproduce at the same rapid rate as domesticated pigs, their numbers have grown exponentially over the years to an estimated six million across the US, with half in the southern state of Texas.

And as the amount of land used for growing crops has expanded, the hogs have had more opportunities for food and shelter.  Large crop fields are like a free buffet, and also provide places for them to sleep and hide from people. Though some have been moved to create hunting opportunities, it has led to the establishment of new and destructive populations. 

They eat crops, kill farm animals and damage property, both in the countryside and in cities. According to John M. Tomeček, a wildlife biologist at Texas A&M University, they cause “in excess of $500 million (€461 million) of damage” annually. 

The environmental damage that they do is much harder to quantify but includes their appetite for the seeds of native trees and eggs of local birds and turtles. But they also damage fragile soils by rooting for food and pollute waterways with their feces. In their natural habitat and in other parts of the country they can be hunted by bears and occasionally mountain lions. In Texas, however, they have no predators.

A field of crops flattened and devoured by wild hogs in TexasImage: USDA APHIS

Invasive species around the world

This is a characteristic shared by many invasive species around the world, such as the lionfish that is native to the South Pacific and Indian oceans but is taking over the Caribbean and Mediterranean, or the Chinese mystery snails native to Asia that are causing problems in Canada and the United States. When a non-native species settles in a new habitat, if there is nothing to keep it in check, it can be incredibly hard to control its spread. 

According to theIntergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), invasive species have played a key role in 60% of global plant and animal extinctions. Annual damage from them has now reached over $423 billion (from 2019 figures), a number that has quadrupled every decade since 1970.

Morelia Camacho-Cervantes, a biologist and director of the invasive species lab at the National Autonomous University of Mexico, says the best way to stop non-native plants and animals from taking over is to prevent them from becoming established populations. 

"Once they have arrived where they don't belong, you would have to eradicate them pretty quickly,” she said. "And by eradicating I do mean killing.”

Can invasive species be eradicated?

There are various ways that this can be done. Animals can be trapped in large groups first and killed, or poisoned. With intelligent feral hogs, experts say it's best to eradicate the whole group, called a sounder, so that they can't teach each other how to avoid humans.

In Texas, people can pay to hunt the hogs from helicopters, which as the easiest way to kill the whole sounder in one go, is the method suggested by the United States Department of Agriculture (USDA). In many cases, such as invasive lanternflies in the Northeastern United States or goats and rats on the islands of Mexico, the authorities encourage people to kill invasive species. 

From the fields and oceans to the kitchen

For some, being able to eat an invasive species makes the call to kill them easier to stomach. In the Mexican Caribbean, for example, edibility has encouraged the population to play a role in getting rid of lionfish. 

"Locals started fishing with the purpose of consuming it,” said Camacho-Cervantes. "And then they were very creative with the recipes they were making, and they were selling a lot. So they were fishing a lot. And now they have populations that are very small.”

The feral hog numbers in Texas are not yet under control and given the rapid rate at which they can reproduce, Griffiths doesn't see that happening. "We have to kill something like 70% of them every year to keep the population where it is,” he says, expertly breaking down a dead hog.

Still, he points to another advantage of eating the hogs that roam free in Texas. "Every pound of feral hog that we're able to serve is also one less pound that's coming out of a broken industrial meat system.”

National Invasive Species Information Center
https://www.invasivespeciesinfo.gov/terrestrial/vertebrates/wild-boar  

NOAA Fisheries: Impacts of Invasive Lionfishhttps://www.fisheries.noaa.gov/southeast/ecosystems/impacts-invasive-lionfish 

Invasive species around the world (IPBES Report): https://www.ipbes.net/IASmediarelease