A Possible Solution for Feral Pigs
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Most of you probably know what kind of issues that feral pigs have caused; they cause roughly 1.5 billion dollars in damage within the United States, according to the Animal and Plant Health Inspection Service (APHIS), a subset of the USDA. This is mostly due to the way of their feeding habits, which includes feeding on most vegetative matter. They mostly feed by means of rooting, meaning that they dig up plant roots and eat them, causing an incredible amount of damage to the land. Not only this, they also create large wallows to “bathe” in, completely destroying the area and its surroundings. On top of this, the dense populations of feral swine create a risk for disease transfer, increasing the possibility to spread disease to other animals, pets, and even people. Finally, their overall high densities increase the likelihood for car collisions, creating a risk for public transportation. With all of that said, feral pigs are a problem to say the least.
So what can we do to control feral hogs, and to limit the spread of these pigs into parts of the country that don’t have them? Well, unfortunately we will never completely get rid of feral pigs. It has become a huge industry in the Midwest and south to hunt feral pigs. Through strict regulation, some states even offer (through private companies) hog hunts from helicopters. With all of this control taking place, though, they’re populations will never be ridden of. Pigs in general are extremely prolific breeders (also called fecund), and even an attempt to decrease populations will be near impossible.
Or will it?
Have you eaten your share of bacon today? I know that I sure have, and if you’ve eaten any bacon today, than you’ve consumed sodium nitrite.
Sodium nitrite is a preservative used for curing meats, used heavily in the making of bacon and other bacon-like products. I’m going to leave out the technicalities of the use of this ingredient within products, but know that it is used very sparingly within foods.
Under high dosages, sodium nitrite can be lethal if consumed. The molecule causes methemoglobinemia, a condition that basically removes the ability of blood to transport oxygen to the rest of the body, causing death. I should also mention that this death is believed to be mostly painless and ethical.
It just so happens that members of the swine family do not possess the ability to metabolize relatively lower amounts of sodium nitrite. In other words, other animals can metabolize higher amounts of sodium nitrite, whereas members of the swine family cannot.
So what does this mean for feral hog control? Well theoretically, sodium nitrite could be used in a mostly directive manner towards feral pigs, so that they are the only animals that can be killed by this poison. This would be furthered by the use of specialized feeding areas – enclosures that would exclude most animals except hogs, and feeders that would exclude anything other than hogs. It’s thought that this triple-manner of safety would make the poison safe for use in the environment. Not only this, but the poison would be highly effective for the intended targets.
I should also mention that sodium nitrite does bioaccumulate within the pig’s body after consumption. This means that sodium nitrite does not stay inside the pig’s body after it has been consumed for very long. The half-life of intravenous sodium nitrite is a little under an hour, and in about 5 hours of consumption there is about 1.5% of the sodium nitrite remaining within the body. This also means that if the hog did not eat the threshold amount of sodium nitrite to initiate death, than the pig would be poison free within several hours (this is important for ethical purposes).
This sounds amazing, right? Yeah, it does. A recent study looked at its effects on predatory mammals (specifically coyotes) and found that it had no effect (Snow et al). Oddly enough, 100% of coyotes that consumed large amounts of sodium nitrite vomited almost immediately, nearly completely removing any metabolize-able sodium nitrite from their system. With this said, I think that further studies need to be performed to observe effects on smaller mammal species (foxes, badgers, etc.).
Unfortunately, there has been a large set back with the entire sodium nitrite project. A recent trial for use was performed using the mentioned above tactics, including the fence and feeder. The hogs went into the fence and started feeding. The poison, being in a mash-like feed, was eaten very messily (as hogs do). The hogs would eat the feed and casually walk out of the enclosure, dropping and throwing the poisoned feed everywhere, including outside the enclosure. Well, birds began to feed on the poisoned mash, resulting in a nearly 200 bird die off in the area. The huge die off resulted in an immediate temporary shutdown of the project, and ideas of how to negate this are currently in the works.
It was in hope that the sodium nitrite feed would be ready for EPA – controlled distribution by 2021, but this bird die off will now result in a delayed release. The company at the forefront of the creation of the poison says that they believe that a different mixture with a different overall texture will solve the issue of the messy hogs.
At this point, I should mention that the consumption of the sodium nitrite by hogs does not accelerate the bacon-curing process (this was my initial question).
It will be interesting to watch this project move forward over the next few years. Texas is at the forefront of the project, as they are desperate to help their farmers and ranchers with their hog issues. I am also wondering as to how effective that the project will be once it is initiated; will this result in limited area-based control, or will it be able to control large, landscape-scale populations? Will the hogs become educated about the poison, resulting in lost effectiveness over time? Only time will tell. I should also mention that Steven Rinella recently spoke with Carter Smith, Executive Director of Texas Parks and Wildlife Department, about the issue. If you’re interested in hearing their discussion, it’s on episode #177 of the MeatEater podcast.
I hope you enjoyed this volume of Jake’s Journal, as I enjoyed writing it. Issues like this interest me, as they are ever-complex and constantly changing. If you have comments regarding the subject, feel free to shoot me a message, as I’d be happy to converse. As always, if you have a topic that you’d like me to discuss, email me your topic and I will do my best to provide you with answers.
Once again, thanks for reading, and don’t forget to sign up for the newsletter.
Citations
Snow, N. P., Horak, K. E., Humphrys, S. T., Staples, L. D., Hewitt, D. G. and Vercauteren, K. C. (2019), Low secondary risks for captive coyotes from a sodium nitrite toxic bait for invasive wild pigs. Wildl. Soc. Bull.. doi:10.1002/wsb.984