12-15M-year-old juvenile T. rex, "Teen Rex," fossil discovered in North Dakota, providing insights into T. rex growth rate and development.

Three children in North Dakota discovered a rare juvenile T. rex fossil in the Hell Creek Formation, estimated to be around 12-15 years old when it died approximately 67 million years ago. Nicknamed "Teen Rex," the fossil is believed to provide valuable insights into the growth rate and development of T. rex. Researchers from the Denver Museum of Nature & Science are studying the fossil, which will be the subject of a new documentary, "T.REX," narrated by actor Sam Neill.