He's helping rewrite our understanding of the prehistoric animal's evolutionary history.
Long, long before cars zipped through Los Angeles and up through the I-15 mountain highway pass toward the Mojave Desert, a large cast of extinct creatures roamed southern California. Fossils from these areas are treasures for paleontologists, who measure and classify these remains to reconstruct the ancient past of the world we inhabit today.
One such creature is the mammoth, which is thought to have diverged from African elephants about 4 million years ago. A small population of mammoths was still roaming Russia’s Wrangel Island when humans were building the first of the Great Pyramids. You’re probably familiar with the mammoth in the form of Sesame Street’s Snuffleupagus, or from dioramas in natural history museums. In fact, long before dinosaur bones were ever discovered, a fist-sized mammoth tooth set off a fossil craze in the United States in 1705, according to Smithsonian magazine. But our knowledge about the evolution of these behemoths is still growing—and along with it, our understanding of the history of an important extinct group and the environment in which they lived.
Mammoths, the "genus" classification of several very different species, are one reason to be excited about paleontology right now. Earlier this year, scientists sequenced the woolly mammoth genome for the first time. The San Diego Union Tribune recently reported that "a treasure trove of ice age fossils," including at least two Columbian mammoths, had been unearthed at a construction site in Carlsbad, California. But you may also think of paleontology as the study of dinosaurs, which died off about 60 million years before mammoths emerged. A 2006 study in the journal Proceedings of the National Academy of Sciences suggested that since 1990, the number of dinosaur genera that we know of increased 85 percent ("genera" is the plural of "genus," a biological classification that's a step above "species"). Still, one paleontologist told Quartz that as much as 76 percent of non-avian dinosaur types that once lived could still be unknown to us.
Scott and Dominic compare mammoth teeth.
Eric Scott, a paleontologist and curator at the San Bernardino County Museum, is at the heart of this flurry of activity around piecing together the prehistoric past. And Scott has a rather unexpected colleague helping him in a mammoth endeavor: 11-year old Dominic Cumo.
Hailing from Victorville, California, Dominic has a condition resembling ALS, otherwise known as Lou Gehrig’s disease, though his parents say doctors are investigating further through genetic tests. His numerous physical challenges include breathing through a ventilator, managing seizures that began when he was just 5 weeks old, faltering speech, and spending most of his time in a wheelchair due to poor control of his limbs. But according to his father, Matthew Bateman, “the way that he approaches this is: ‘Okay, I have this problem, there’s nothing I can do about it, what can I do to better myself? How can I move forward?’”
Dominic’s contagious positive outlook, unshaken by countless hospital visits and the progressive loss of physical abilities, extends to his interest in the ancient past. That passion is what first connected Dominic with Scott a little over a year ago, after his family showed up at Scott’s museum’s National Fossil Day event too late for the scheduled festivities. Scott met with Dominic anyway, and was struck by his enthusiasm; they have been visiting museums and other sites of interest together ever since.
The first mammoths to enter North America were the Southern mammoths, arriving from Asia via the Bering Strait about 1.8 to 1.6 million years ago. They looked like huge elephants with long tusks, reaching as high as 13 feet tall at the shoulder, and are distinct from smaller “woolly mammoths,” which appeared separately on the continent 400,000 years ago.
Based on the available fossil record, it has long been proposed that the Southern mammoth evolved into the Steppe mammoth, which then gave rise to the Columbian mammoth.
But now, Scott and Dominic are questioning that story. Back in 1993, when Scott had only been at his museum for a couple of years, he excavated Southern mammoth remains when a housing construction project in Victorville unearthed them. Discovering fossils this way in Southern California happens more often than you might think. The sediments were later dated to around 375,000 years old—or the later Pleistocene Epoch.
While studying these fossils in 1994, Scott remembered a published but unsubstantiated reference to Columbian mammoths in Victorville. If indeed a Columbian mammoth had lived at the same place and time as the Southern mammoth, that would upend the accepted evolutionary story.
But where was this supposed Columbian mammoth fossil that was written about? To investigate, Scott went to the Natural History Museum of Los Angeles County to examine their collections. He located a tooth discovered in 1934 along the western banks of the Mojave River, about seven miles north of where the Southern mammoth remains were found. It looked like a Columbian mammoth tooth, but he didn’t conduct a detailed analysis at the time.
Since both of these teeth were discovered in the same general area of the high desert where Dominic lives, Scott saw it as the perfect collaborative project. So about a year ago, Dominic joined Scott to help perform some crucial measurements.
Dominic helped count the plates in the unidentified tooth per 100 mm (“lamellar frequency”) and measure the enamel thickness. They came up with a frequency of 6.5 to 7, and an enamel thickness of 1.5 to 2.1 mm.
They then compared this to a third molar from the Southern mammoth, which has a lamellar frequency of slightly less than 4.5, and an enamel thickness ranging from 2.3 to 4.0 mm. The unidentified tooth was clearly different. And, according to published studies, its measurements matched a Columbian mammoth.
If indeed a Columbian mammoth lived at the same time as a Southern mammoth in California, that would be very surprising, as the Columbian mammoth is regarded as a much later species that evolved from the same lineage, said Ross MacPhee, curator of the department of mammalogy at the American Museum of Natural History in New York, who was not involved in this research.
In other words, if Scott and Dominic’s theory is confirmed, it could change the evolutionary story of these mammoths in North America as currently understood by many paleontologists. Instead of the Southern mammoth giving rise to the Steppe mammoth, which then gave rise to the Columbian mammoth, there could have been more branching going on in the family tree.
But did the two mammoths that Dominic and Scott studied live at the same time? They were both apparently recovered from roughly the same “upper fluvial unit” in an area mapped by the USGS in 2003, suggesting to Scott that they are not too far apart in geologic age. The exact place where the Columbian mammoth tooth was discovered has not been dated, however, and because it was excavated in 1934, there is some uncertainty about where that was.
“Their presence in the same river basin is interesting but not dispositive,” MacPhee said. In other words, though these findings are compelling—indicating that both mammoth species likely lived during a similar, or even the same, time—nothing can be completely settled without more evidence.
Still, according to Scott, even if the two mammoths are separated by tens of thousands of years, that’s not enough time for the Southern mammoth to directly evolve into the Columbian mammoth. It appears that Southern mammoths survived in Victorville, California, while elsewhere, the same species was evolving into Steppe mammoths, which then evolved into Columbian mammoths. And the Columbian mammoths apparently made it to Victorville, too.
Paleontologists can discuss these findings and their interpretations directly with Scott and Dominic at the Society of Vertebrate Paleontology meeting in Dallas in October. The abstract describing their research, which also received input from two of their colleagues, has been accepted for a poster session. Scott and Dominic also have plans to seek publication of their findings in a journal.
Says Dominic, amid the pumping sound of his breathing machinery, “The question is, HOW did it get here, and WHY?” Indeed, these are the very questions at the heart of paleontology, and there may never be easy answers. Still, Scott and Cumo are planning a trip to Barstow to see the famous fossil beds there—at 19 to 13 million years old, they’re much older than mammoths—where questions remain for still more remnants of prehistory. In the meantime, they are still good friends, and spent a recent Saturday afternoon watching Guardians of the Galaxy.
“Were he another child, I might do many of the same things—but the emphasis would be on going to school, studying hard, volunteering at a museum, and so forth. In Dominic's case, time is more of a critical factor. So I try to make extra time for him, and be ready to just hang out and chat,” Scott said.
Paleontology is part of Dominic’s vast assortment of interests and achievements. A Yoda doll on his wheelchair wears a martial arts uniform, reflecting Dominic’s black belt in Tae Kwon Do. In his bedroom is a whiteboard labeled “Bucket List,” noting wishes that would be ambitious for anyone, and experiences that few get to have. There are checkmarks next to such shows as “America’s Got Talent” and “American Idol,” as well as “NASCAR,” “NBA game,” “Yankees” and “Joel Osteen.”
Among the unchecked (for the moment): “Dig w/ Eric Scott.”