Woolly mammoths were headed toward extinction 10,000 years ago, a fate now largely blamed on human hunters who killed the enormous mammals more quickly than they could reproduce. It was the beginning of a long, dysfunctional relationship between humans and wildlife that continues today.

This week, a mammoth possibly killed by humans 10,000 to 15,000 years ago emerged from soy fields about 50 miles west of Detroit. It was found by farmer James Bristle and his neighbor Trent Satterthwaite, who were reportedly digging to drain water from the field. At first, they couldn't figure out what they were seeing.

"It was probably a rib bone that came up," Bristle tells Ann Arbor News. "We thought it was a bent fence post." Upon closer inspection, however, it became clear even to untrained eyes this was no fence post. "We knew it was something that was out of the norm. My grandson came over to look at it; he's 5 years old, he was speechless."

After finding the bones Monday night, Bristle called the University of Michigan Tuesday morning to report his find. Paleontologist Daniel Fisher arrived to inspect it Wednesday, and by Thursday morning he had confirmed it's a woolly mammoth. He estimates the animal was about 40 years old when it died, sometime around the late Pleistocene Epoch. It was likely hunted by humans, he says, who killed it and stored the remains in a pond as a way of preserving the meat for future use.

It's still too early to tell exactly how it died, Fisher tells Detroit's WWJ-TV, "but the skeleton showed signs of butchering." The site has "excellent evidence of human activity," he adds. "We think that humans were here and may have butchered and stashed the meat so that they could come back later for it."

Woolly mammoths once roamed a swath of Eurasia and North America during the Pleistocene, and most became extinct by 10,000 years ago — a demise that has been linked not only to humans, but also to changing climates at the end of a glacial period. Yet climate alone can't explain the disappearance of megafauna like mammoths, according to a 2014 study, and many experts now believe warming weather weakened their populations before humans dealt the final blows.

(A small population of mammoths actually survived until just 3,600 years ago, thanks to their luck of living on a remote, human-free island in the Arctic Ocean.)

North America was also home to mastodons, a more primitive species that was smaller and less closely related to modern-day elephants than woolly mammoths are. While several hundred mastodon sites have been found across Michigan over the years, Fisher says there are only 10 sites similar to the new discovery, with so much of a mammoth skeleton unearthed. Fisher ended up retrieving about 20 percent of this mammoth, he tells the Detroit Free Press, including its skull and tusks.

Mastodons, like the one pictured at right, were smaller and lighter than mammoths. (Photo: Wikimedia Commons)

Although it's being called a woolly mammoth for now, Fisher says the newfound fossil may actually be a closely related species known as a Jeffersonian mammoth. The bones are being temporarily stored nearby, according to the Free Press, and it remains unclear where they'll eventually end up. Their research value will be determined once they've been cleaned and dried.

In the meantime, those who helped with the excavation tell the Free Press they're just glad they got to take part in such a mammoth discovery.

"It's a pretty exciting day. I've been digging for 45 years and I've never dug anything up like that," says James Bollinger, an excavator and local resident who brought in heavy machinery to speed up the dig. "You have a better chance of winning the lotto than doing what we just did," Satterthwaite adds.