To Study Mass Die-Offs, Scientists Dumped 15 Tons of Feral Pig Carcasses Into a Field

The world’s recent spate of disasters has served as nothing if not a reminder of the fragility of life. Warming oceans, stripped of their fish, have spat thousands of starved birds onto shores; fires raging across Australia have felled up to a billion of its animals. But the tragic tales of these mass die-offs don’t simply end with the extinguishing of life: Researchers studying the aftermath of these events are now finding that the cadavers that litter devastated landscapes can alter the ecology of their surroundings for years to come.

From a bird’s eye view, that might not sound like much of a surprise. After all, decomposition has a way of changing who does and doesn’t want to pay a particular location a visit. But as Sabrina Imbler reports for Atlas Obscura, understanding the subtleties of these changes is becoming an increasingly urgent matter. Long considered rare and elusive, animal mass mortality events appear to be on the rise—and as climate change continues to reshape our planet, these losses may become the norm.

That’s why a team led by Brandon Barton, an ecologist at Mississippi State University, recently dumped 15 tons of fresh feral hog carcasses—or about 200 bodies—into a large prairie grassland in Oklahoma. An invasive species in the south and southeast, these pigs are common targets for locals looking to protect their property, and all came to the researchers as donations. After hauling the bodies in, the team split them into 24 separate plots, parceling different numbers of pigs into each patch of grass and fencing and netting some, but not others, to keep scavengers out.

Then, they waited.

Decomposing wild boar carcasses

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The first thing that hit them was the smell. “It gags you so that you can’t breathe, and seizes your lungs up,” Barton tells Atlas Obscura. “It’s incredible.” To protect themselves, the team suited up with sanitary masks and trucked in gallons of Purell and soap.

These were wise precautionary measures—especially when rivers of maggots began to flow from the corpses, carpeting entire swaths of flesh and soil with their writhing white bodies. Green blades of grass peeking up between the pigs soon blackened with the descending forms of full-grown flies, swarming in like a cloud.

Larger animals, too, began to trickle into the unfenced plots, feasting on what remained of the pigs and the insects that coated their rotting flanks. Bodies that were protected from scavengers degraded as well, but in a much different way: Gas, produced by microbes feasting on their interiors, eventually ruptured the cadavers like macabre balloons, the researchers wrote in a piece for the Conversation.

The putrefying pigs eventually began to leach gobs of nitrogen into the soil—an inundation of nutrients that ended up overwhelming and killing local microbes and plants, reports Matt Simon at Wired. The grasses were fairly quick to bounce back in plots where only a single hog carcass had been left. But patches with ten or more stayed brown and dead for months. And a year into ecosystem recovery, some of the bacteria still hadn’t bounced back, environmental microbiologist Heather Jordan tells Wired. The devastation was worst of all in the plots closed off to scavengers, whose presence—though oft maligned—actually helps redistribute and process decaying material away from single sites.

“There are very few people fighting for the vultures,” Barton tells Atlas Obscura. “But when you don’t have those guys there to clean up, we lose so much.”

As the researchers write in the Conversation, these findings could have sobering implications for the fires devastating habitats in Australia, and the continent’s potential for recovery. As species are stripped from the landscape, there’s little guarantee that all will return. In the wake of a mass die-off, ecosystems may find themselves changed for good. “We know very little about mass mortality events in general,” Jordan tells Wired. “But we know even less about the impact of these in fire.”

Katherine J. Wu | | READ MORE

Katherine J. Wu is a Boston-based science journalist and Story Collider senior producer whose work has appeared in National Geographic, Undark magazine, Popular Science and more. She holds a Ph.D. in Microbiology and Immunobiology from Harvard University, and was Smithsonian magazine's 2018 AAAS Mass Media Fellow.