Four friends spending the day exploring a creek in eastern Iowa found a mastodon tooth, according to local NBC affiliate KWWL.
On what appeared to be a normal summer day, 11-year-old Chase Redfern, 10-year-old Brynlee Volker, and 12-year-olds Michael Koch and Brylie Volker were gathering twigs.
"We were going to build a dam to hold back all the water and we wanted to clear out the rocks, so it wouldn't be all rocky," Volker told KWWL.
They then saw something large hooked onto a twig and the boys went to investigate.
"I saw something flip over so I picked it up and realized it probably wasn't a rock," said Redfern.
They thought it was a dinosaur tooth and ran to tell someone. Naturally, the adults didn’t believe them.
"We ran up by the barn where all the adults were sitting, and we said we found a tooth," said Volker. "They thought it was just like a little mini rock like it wasn't going to be anything, and we came back with this enormous thing. It was pretty cool."
A professor at Upper Iowa University speculated that the tooth may have belonged to a mastodon 20,000 years ago. Mastodons are an extinct mammal group related to the modern-day elephant.
Katherine McCarville, an associate professor of geosciences at the university, told KWWL that thousands of mastodon teeth have been found in North America. Most of them, however, were discovered in Siberia.
McCarville also said that the tooth, which was in such good condition, could be part of a finding of much larger remains. She was unsure as to the monetary value of the tooth.
"It's cool that we found it just like here where we live around here, and it's cool because I got to find it with all my friends," Volker said.