Living in the present is all well and good – not for nothing did the psychologist Richard Alpert become famous as the guru Ram Dass with the motto, “Be Here Now” – but human animals also have the precious capacity to wonder where we came from.
This is where archaeology and Colorado come in. It is also where they intersect.
Start first in North Dakota, where Tyler Lyson grew up, in Marmarth, a town of 140 in the southwest corner of the state.
Marmarth is crossed by the Hell Creek geological formation. Lyson began fossil hunting there when he was a child. He spent the rest of his middle school years extracting a fossilized Hadrosaur in unusually good shape, with petrified soft tissue.
Lyson went on to a doctorate at Yale in paleontology. After a stint at the Smithsonian’s Museum of Natural History, he came to the Denver Museum of Nature and Science in 2016, where today he’s the curator of vertebrate paleontology.
Recently, Lyson and a team of other scientists published a significant paper in the journal Science, “Exceptional continental record of biotic recovery after the Cretaceous–Paleogene mass extinction.”
That is worth unpacking.
The mass extinction occurred about 66 million years ago, when an asteroid struck the Yucatán Peninsula, in present-day Mexico, leading to the annihilation of dinosaurs. In the recovery, over millions more years, mammals grew and found their niche at the apex of animal life; for them, it was a lucky strike.
It is the point just after the impact, for about a million years, called the K-Pg interval, that fascinates Lyson and others, because until now, we had such a poor record of it.
In 2016, Lyson and his colleagues were led to Corral Bluffs, a few miles east of Colorado Springs, where he discovered part of a fossilized mammal skull from the K-Pg interval. Then more skulls. They “tell a story of mammalian resilience,” The New York Times reported last week.
“Whereas rat-size mammals survived the extinction event, raccoon-size ones perished. About 100,000 years after the K-Pg ... mammals bounced back, with raccoon-size mammals reappearing. Some 300,000 years after the asteroid struck, more mammals appeared ... Within 700,000 years ... the wolf-size Eoconodons began to thrive.”
This is how we became us.
It is “the most vivid picture of recovery of an ecosystem on land after any mass extinction,” Lyson told The Times.
A crew from NOVA, the public television series, followed the scientists as they explored Corral Bluffs, producing a one-hour documentary, “Rise of the Mammals,” that was just broadcast on PBS stations and is free to stream online.
The documentary animates our mammalian ancestors, such as Loxolophus, who shows up about 300,000 years after the dinosaurs are wiped out. A pure opportunist, Loxolophus is a raccoon-sized omnivore, and cute.
That this record was found in Colorado could be happenstance or even luck, but the other story here, of the resilience of early mammals, is very Coloradan.
Long before humans went through subsistence hunting, agriculture and the boom-and-bust cycles of resource extraction, trying to figure out how to make all this beauty pay, or at least feed us, here was intrepid Loxolophus, whose remains were found at Corral Bluffs. So were those of his successor, the pig-sized Carsioptychus, grown to more than 30 times the size of the largest mammals that survived the extinction, and so successful, like middle-class vegans, it could specialize as an herbivore.
Some say we’re already in the next great mass extinction, with the difference that we have brought this one on ourselves. We hope we at least get a Tyler Lyson in the next go-round.
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