Re-examined mastodon site opens a window to lost world
Since the spectacular 1977 discovery of a mastodon’s remains in Washington state scientists have argued about who or what killed it some 14,000 years ago.
The archaeologist who first investigated the mastodon, Carl Gustafson of Washington State University, became convinced humans had hunted and killed the animal, butchering it for food and materials.
But his view lay outside the more conventional view, which held that humans could not have been involved in the death of the mastodon, a species related to Woolly Mammoths. At the time most archaeologists didn’t even believe humans had arrived in North America that long ago.
“My colleagues at the university would not accept the theory,” Gustafson, now retired, recalled. “When you’re working side-by-side with them in the same building, and they don’t even believe you, well, you get very discouraged.”
Eventually his grant funding ran out, and by the early 1980s only his son remained to work the site with him.
So he waited. And waited. Until the phone rang a few years ago, when Texas A&M University’s Michael Waters called and said he wanted to reanalyze the remains Gustafson had found.
In the three decades since the mastodon discovery the tools of scientific discovery have undergone a CSI-like transformation. Waters wanted to use the new powerful analytical tools to determine whether humans may have, indeed, killed the mastodon.
The key piece of evidence behind Gustafson’s human-caused death theory was a rib bone with another bone embedded in it. A fuzzy, two-dimensional X-ray at the time proved inconclusive, but Gustafson believed the bone had been shaped into a weapon-like point by early Americans hunting large game.
Waters used a high-resolution CT scanner, which took an image every two-thousandths of an inch, to create a three-dimensional image that showed a weaponized bone embedded in the mastodon’s rib.
“The tip of a bone projectile point was as clear as day,” Waters said.
The next step was to figure out the origin of the bone point. Protein and DNA analysis of the bone showed that the bone point itself was fashioned out of a mastodon bone.
Finally Waters and his team performed a modern radiocarbon dating analysis to confirm that the mastodon died 13,800 years ago, plus or minus 50 years. They published their results Thursday in the journal Science.
“Clearly these people were hunting mastodons, and probably harvesting their bones to make tools,” Waters said. “It adds one more piece to the puzzle of trying to understand the first Americans. It’s filling out our picture.”
It’s a picture that’s been radically remade in recent years.