Kids discover extremely rare teen T. rex fossils sticking out of the ground during North Dakota Badlands hike

Three kids hiking in North Dakota made a larger-than-life discovery: a rare teenage Tyrannosaurus rex. The fossil specimen, now nicknamed "Teen Rex," could shed light on how the mighty Cretaceous dinosaur matured.

The three children, ages 7 to 10, came across the young-T. rex fossils while walking in the Hell Creek Formation in the Badlands of North Dakota in 2022, and they helped excavate a series of its bones in 2023.

The partial skeleton, one of only a handful of juvenile T. rex specimens ever discovered, will go on display at the Denver Museum of Nature and Science later this month, coinciding with the cinematic release of a new documentary featuring the discovery, titled: "T. rex."

"Juvenile [T.] rex specimens are extremely rare," Tyler Lyson, a vertebrate paleontologist at the museum who led the "Teen Rex" excavation, said in a statement released by "T. rex" producer Giant Screen Films. "This find is significant to researchers because the 'Teen Rex' specimen may help answer questions about how the king of dinosaurs grew up." 

"Teen Rex" was 25 feet (7.6 meters) long and weighed about 3,500 pounds (1,600 kilograms) when it died more than 66 million years ago, according to Catalyst, the museum's online magazine. For comparison, a full-grown T. rex reached about 40 feet (12 m) in length and weighed around 8,000 pounds (3,600 kg). 

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Brothers Liam and Jessin Fisher, 7 and 10 years old, were with their father, Sam Fisher, as well as their 9-year-old cousin Kaiden Madsen, when they noticed a large fossil sticking out of a rock formation. Sam Fisher was a former classmate of Lyson, so he alerted the paleontologist to their discovery of the then-unidentified dinosaur.