Scientists now know that the mammoth being excavated just south of Kennewick likely was what would be considered middle age for a human when it died.
A study this summer of the animal’s lower jaw with one fairly complete tooth showed it reached the age of about 40, give or take about three years, before perishing in an Ice Age flood about 17,450 years ago. Without that misfortune, it might have lived another 20 years.
The mammoth bones were discovered in 2000. Between then and the establishment of the MCBONES Research Center foundation of the Coyote Canyon Mammoth Site some bones, including the lower jaw, ended up in private hands.
Because the lower jaw can be used to determine the age at death of a mammoth, Bax Barton, director of research at the site, received permission to visit and study the jaw late last fall, said Gary Kleinknecht, education director for the site.
Mammoths had six sets of four teeth in their lifetimes, Kleinknecht said.
This animal — it still is not known if it was male or female — was on its sixth set. The final set usually comes in about age 30 and is done for at about age 60, Kleinknecht said.
The tooth grows forward and some of the tooth of this animal was pristine, indicating it had not been completely exposed yet.
Researchers can also study the ridges of the tooth, making a series of complicated measurements, comparing them to modern-day elephants to learn more.
Wooly mammoths have been found farther north in Canada. In the Northwest United States down to Mexico, typically bones of Columbian mammoths — a separate species — have been found.
“We’ve been telling everyone from the get go this is a Columbian mammoth,” Kleinknecht said.
A look at the ridges on the tooth of the Coyote Canyon mammoth confirmed that, as suspected, it was a Columbian mammoth.
Researchers already knew that the bones were from an animal that was neither a teenager nor a senior citizen, in part because it did not have much arthritis evident. It likely stood 10 to 13 feet tall at the shoulder, making it larger than the modern day Asian or African elephant.
Volunteers had hoped to find and excavate the pelvis in 2013, but were unsuccessful. If they do find it, it should confirm whether the animal was male or female.
Finding mammoth bones in Washington state left from the Ice Age floods is not unusual. But they are usually found when construction excavation is being done and there’s not time to study them thoroughly.
This dig site is different. The land was donated for research and education. The site is being excavated to exacting standards that modern paleontology and archaeology require to find out as much as possible not only about the mammoth but the times it lived in and the Ice Age floods that likely deposited its body near the Tri-Cities.
Buckets of dirt are carefully sifted to collect other animal bones, what’s left of insects and plant seeds to capture data to show how plants and animals changed over time, reflecting different environmental and climate conditions.
Battelle, which operates Pacific Northwest National Laboratory in Richland, has donated money and allowed interns to help study the site.
Their work has looked at different data sets to confirm that the mammoth lies in an Ice Age flood deposit.
Their study, along with radiocarbon dating of a bone to about 17,450 years ago, “means that we can now assign a date to one of the Ice Age flood events that inundated the Tri-City area,” said George Last, geology research coordinator.
The dig site is at an elevation of about 1,060 feet and floods may have been deep enough to reach the area about seven times. The high water mark for Ice Age floods in the Tri-City area is at an elevation of about 1,250 feet. In comparison, the McNary pool of the Columbia River is at an elevation of about 340 feet.
Researchers don’t know exactly how the mammoth died. It could have died elsewhere and been carried by flood waters to the Tri-Cities.
That’s the hypothesis that Kleinknecht favors. The mammoth was found in the ground with its feet up, the same way a carcass would have floated in the water. The bones are not too beat up, indicating it may not have been carried too far by the flood waters.
Other hypotheses are that it lived nearby and became mired in mud and died or that it was encased in the ice flows that floated with flood waters into the Tri-City area.
The skeleton that has been unearthed so far has been largely intact, but the right ribs were jumbled and had bite marks on them, as if animals had been feeding on the carcass before it was buried.
Student research has concluded that the teeth marks are from a rabbit and two types of rodents, Kleinknecht said.
So far 74 bones and bone fragments have been excavated, including 14 ribs and one partial rib, vertebrae and foot bones. This summer some additional ribs are expected to be excavated by volunteers.