An artist's depiction of the teen T.Rex found in North Dakota (Credit:
Andrey Atuchin/ Denver Museum of Nature & Science/ CC-BY-SA-2.0)

On July 31, 2022, Jessin Fisher (10), his brother Liam (7), and cousin Kaiden Madsen (9) went fossil-hunting in the Hell Creek Formation in the North Dakota Badlands. The area is rich in dinosaur bones, and the trio hoped to find a few. Little did they know that they were about to stumble upon one of only a handful of juvenile Tyrannosaurus rex (T. rex) skeletons ever found!

The events leading to the exciting discovery began when Liam and his dad, Sam Fisher, saw a long, gray-white bone sticking out of the ground.

“My dad hollered for Jessin and Kaiden to come, and they came running up on the butte,” Liam told The Washington Post. “Dad asked, ‘What is this?’ and Jessin said, ‘That’s a dinosaur.’”

Dr. Tyler Lyson with Liam, Jessin, and Kaiden (Credit: Denver Museum of Nature & Science/ CC-BY-SA-2.0)

Sam sent a photo of the fossil to Dr. Tyler Lyson, a paleontologist at the Denver Museum of Nature & Science. The expert confirmed Jessin's hunch. After receiving the necessary permits in 2023, Dr. Lyson set up an excavation team, which included the three boys. He had initially thought the bone was that of a duckbill dinosaur, a more commonly found species. But shortly after arriving at the site, the scientist and Jessin found what appeared to be a T. rex tooth. Further digging revealed three more teeth attached to a jaw.

"Instead of finding cervical vertebrae, we found the lower jaw with several teeth sticking out of it," Dr. Lyson told the Associated Press. "And it doesn't get any more diagnostic than that, seeing these giant tyrannosaurus teeth staring back at you."

The T. rex fossil was preserved inside a massive sandstone (Credit: Denver Museum of Nature & Science/ CC-BY-SA-2.0)

The dinosaur bones were encased in a massive 6,000-pound (2,700 kg,) eight-foot-wide (2.4-m) chunk of sandstone. It took 11 days to excavate. The incomplete, but well-preserved, skeleton included the dinosaur's lower leg, hips, pelvis, tail vertebrae, and most of its skull.

The researchers estimate that the T. rex was probably 25 feet (7.6 m) long and 10 feet (3 m) tall. It probably weighed around 3,500 pounds (1,600 kg), about two-thirds of the size of a full-grown adult. They believe the dinosaur was between 13 and 15 years old when it died approximately 67 million years ago.

"Juvenile [T.] rex specimens are extremely rare," Dr. Lyson said. "This find is significant to researchers because the 'Teen Rex' specimen may help answer questions about how the king of dinosaurs grew up."

The juvenile T.rex fossils went on display at the museum on June 21, 2024 ( Credit: Denver Museum of Nature & Science)/ CC-BY-SA-2.0

Liam, Jessin and Kaiden affectionately named the young dinosaur "The Brothers." It went on display at the Denver museum on June 21, 2024. The exhibit, entitled "Discovering Teen Rex," includes a documentary chronicling the journey of the boys' remarkable discovery.