Massive 10,000-Year-Old Mammoth Jaw Pulled Out Of Florida River

Published November 21, 2023

The mammoth jaw was discovered in Florida's Peace River by self-proclaimed fossil junkie "Captain John" Kreastoulas.

John Kreastoulas With The Mammoth Jaw

Fossil Junkies / FacebookJohn Kreastoulas with the mammoth jaw he found in the Peace River.

A self-proclaimed fossil junkie in Florida made the discovery of a lifetime when he found an incredibly rare, fully intact mammoth jaw while diving in the alligator-infested waters of the Peace River.

John Kreastoulas has been interested in fossils ever since he was a little kid, and has since evolved that fascination into a career.

“As a kid, my grandmother took me to the library, and they had a little fossil dig. There was a little shark’s teeth in a gravel box kit, and I was hooked,” he told a local NBC outlet.

Now known locally as Captain John, Kreastoulas runs the fossil hunting organization Fossil Junkies Dig and Dive Charters, which provides guided tours for amateur fossil hunters near the city of Arcadia, Florida.

“I strictly only dive in the wintertime,” Kreastoulas said. “When the water gets cool like this, the gators are more dormant.”

But when Kreastoulas dove into the waters on November 6, he was so distracted by his fossil search that he failed to notice an alligator swimming right by him. Luckily, a friend was with him and pulled him out of the water.

“So I went up to the surface, and when I got back up there, [my friend] said, ‘You didn’t see that big gator?’ I said, ‘No, I wasn’t looking for gators, I was looking for fossils!” said Kreastoulas.

Then, while scouting and exploring that same section of Peace River the next day, Kreatsoulas came across what he at first assumed was a log — only to realize, upon closer inspection, that it was actually a large, fossilized mandible.

“I grabbed onto it just to hold on for a second, and I realized, ‘Wait for a second, that’s not a tree; that was a mammoth jaw,'” he said.

The jaw weighs about 60 pounds and was found alongside a set of molars. Although Kreastoulas doesn’t know exactly how old the mammoth jaw is, he said he estimates that it is around 10,000 years old.

Kreastoulas plans to take the jaw to Ancient Artworks in Tampa to have it restored and the molars attached back onto it. He also said he would register the fossil with the State of Florida, meaning they could choose to take it, if they so wished. If not, Kreastoulas said, he’d be proudly displaying it in his living room.

So far, the mammoth jaw remains officially unidentified, but according to the National Park Service, the archaeological record shows that the Columbian mammoth was prominent throughout North America during the Pleistocene Epoch.

Columbian Mammoth Hunt

Wikimedia CommonsAn artist’s rendition of what an ancient hunt for a Columbian mammoth may have looked like.

Largely due to warming temperatures and hunting by humans, they went extinct towards the end of the last ice age, between around 13,000 and 10,000 years ago, which would align with Kreastoulas’ estimate.

This discovery further solidifies Florida as a hotbed for fossil research. Just last year, researchers came upon a massive graveyard for an ancient elephant relative known as the gompothere.

These massive beasts lived around 5.5 million years ago and had four tusks. The site of the grave, known as Montbrook, was especially significant as it contained near-complete gompothere skeletons, which looked “as if the animal had just laid down and died,” one researcher said.

It’s likely that the gompotheres were either transported to the site of the mass grave, or all somehow died in the same spot at different points in time. Some researchers suggested that there had once been a bend in the river that flowed through the region, and that the dead gompotheres all became stuck at that point.

In any case, it’s clear that Florida is a fantastic spot for fossil research, and could unlock even more mysteries about the prehistoric world.


After learning about the discovery of this mammoth jaw in Florida, read about the eight-year-old Russian girl who found woolly mammoth bones while fishing with her father. Or, read about the reindeer herders who discovered 10,000-year-old mammoth bones with the ligaments still intact.

Austin Harvey
A staff writer for All That's Interesting, Austin Harvey has also had work published with Discover Magazine, Giddy, and Lucid covering topics on mental health, sexual health, history, and sociology. He holds a Bachelor's degree from Point Park University.
Maggie Donahue
Maggie Donahue is an assistant editor at All That's Interesting. She has a Master's degree in journalism from Columbia University and a Bachelor's degree in creative writing and film studies from Johns Hopkins University. Before landing at ATI, she covered arts and culture at The A.V. Club and Colorado Public Radio and also wrote for Longreads. She is interested in stories about scientific discoveries, pop culture, the weird corners of history, unexplained phenomena, nature, and the outdoors.