Artichoke farmers plowing their fields in northern California have reaped a strange harvest: a trove of exotic animal fossils, including camel, mastodon and — most striking of all — the first known remains of a Columbian mammoth with strands of its hair still intact.
Since the dense deposit of Ice Age bones was first unearthed in 2011, near Castroville in Monterey County, archaeologists and paleontologists have been working to tease data out of the remains, and also piece together how so many animals could end up in the same ancient grave.
“We have bison, we have camel, we have horse, we have mastodon — that’s a pretty diverse range of animals for that one spot,” said Mark Hylkema, an archaeologist with California State Parks who’s coordinating the all-volunteer effort to study the site.
“So it begs the question: How did so many bone elements get deposited at this place?”
The tantalizing find has drawn experts from across the U.S. and Europe to help excavate, preserve, and analyze the remnants.
But much of the research has understandably focused on the mammoth, the first of its species to surrender a bit of its soft tissue.
It’s just a small tuft of hair, but genetic information extracted from it, as well as wear patterns on the animal’s teeth, indicate that the specimen was a 46-year-old male Columbian mammoth.
It was small for its species, standing perhaps 3 meters tall at the shoulder.
But the most vivid revelation to be gleaned from the hair was also probably the most obvious.
“What was particularly significant is that the hair was red,” Hylkema said. “It was the same color of my golden retriever.”
“We can envision cattle on the landscape today,” he added. “Picture herds of red-colored mammoths.”
Unfortunately, Hylkema said, the mammoth’s remains are too poorly preserved to provide much more genetic information, at least for now.
So those hoping that clones of the Monterey mammoth might one day roam the West will have to wait for another specimen to be found.
“The geneticist was able to positively identify it as Columbian mammoth specifically,” Hylkema said. “But he was unable to get enough DNA to unravel its genome.”
The whole genome would not only provide molecular instructions on how to make a Columbian mammoth, but it would also reveal crucial information about how the animal really lived and looked, as well as its evolutionary relationships to other proboscideans, including elephants, mastodons and the bizarre, extinct gomphotheres. [Read about the first evidence of gomphothere-hunting: “Ancient Clovis Elephant-Hunting Camp Discovered in Mexico“]
But simply discovering the tissue is a significant find, Hylkema said.
“Our interest was, first, is it really mammoth hair? Because you don’t know what you’re looking at when it’s in position,” he noted. “So getting that confirmation was still a celebratory moment for us.”
For now, the next-biggest question on the minds of Hylkema and other archaeologists is whether the mammoth ever met — or met its end at the hands of — humans.
“We’re archaeologists, so we’re interested in finding out if there’s a cultural overlay with this animal, since we know that Native Americans were in the Americas when mammoths roamed the landscape,” he said.
“So we we’re hoping for the possibility of finding one of those kill sites, which is a needle in a haystack.”
However, part of the process of determining the animal’s possible proximity to people involves dating it, which so far has proved as fruitless as sequencing its genome.
“We tried running a radiocarbon date on some of the bone itself — the bone was pretty fresh — but when they do AMS [accelerator mass spectrometry] dating, they’re looking for the fatty tissue in the bones. Unfortunately, in this case, water had removed the fat, so we were unable to date the bone directly.”
The team did find a layer of seashells underneath the mammoth, which were successfully dated to 27,000 years ago. But that date, paired with the extinction of the Columbian mammoth some 10,000 years ago, leaves a rather large window.
So now the team is turning to other clues, like testing traces of freshwater molluscs found among the animals, which can help secure a date, and scrutinizing the bones for cut marks or other signs of butchering by humans.
While artifacts remains elusive, Hylkema says he continues to probe the initial question posed by the huge trove of bones: How did the carcasses of so many different animals become concentrated in one place?
“We did not find any cultural evidence, except for one thing that still dogs us: It was the high frequency of disarticulated elements laying around this guy,” he said of the mammoth.
The deposit of fossils is so dense that the team only stopped excavating because of constraints of time and staffing, he said. Many more bones remain in the ground.
“It was like a box of Kleenex, where you pull out a sheet and another one’s right behind it,” he said. “At some point, you just have to say, that’s it, we gotta stop.”
But the site was not some kind of mud pit or natural trap that could have swallowed up the animals, he added.
The bones are scattered, jumbled, and broken into pieces — almost as if having been processed and then cast aside.
“It’s not like the La Brea tar pits, where they all fell in and just became nicely preserved,” he said. “Our guy looks like he stepped on a paleolithic land mine. It’s all pieces.” [Read about a ‘dinosaur death trap’ found in Utah: “Dinosaur Death Trap Found in Utah May Contain Raptor Family, ‘Horse Dragons,’ Cannibalized Baby“]
And then there’s the sheer variety of animals found — not only mammoth and mastodon, which were known to have been hunted by humans, but also bison, camel and birds of prey. [Read: “Fossil Camel Discovered in Oklahoma by Oil Workers“]
“If you were to dig randomly in a landscape, even in an archaeological site, you’d rarely find that kind of diversity — unless you’re in a village refuse site or something like that,” he said.
But Hylkema and his team are a long way from claiming that the artichoke farmers unearthed a midden left by Ice Age hunters.
“We all know that Paleoindian finds can be pretty controversial, so you want to have a solid case when you start talking about cultural associations,” he said. “A lot of the time, if you don’t have a Clovis point stuck in the bone, people are very skeptical.”
So for now, archaeologists, paleontologists, and geneticists will continue to pore over the fascinating finds they already have in hand.
From here the project’s objective’s include studying the mammoth’s teeth to learn about its diet, analyzing the rich microscopic fauna that have been found among the bones, and continuing to pin down a date.
“It’s little clues that come together to form a larger story,” Hylkema said, “and our larger story has yet to be written.”