Overview
- Researchers used polarized-light microscopy, four ring-counting approaches, and a composite statistical model to build a detailed growth curve from multiple specimens.
- T. rex underwent a rapid teenage growth spurt between roughly ages 14 and 29, adding about 800 to 1,200 pounds per year before a slower 10–15 year subadult phase.
- The analysis indicates the dinosaur spent much of its life at mid-body size, suggesting shifting ecological roles before reaching apex status.
- The dataset spans 17 tyrannosaur leg bones, largely from Montana and North Dakota museum collections, and is described as the most comprehensive for T. rex growth.
- Outlier specimens nicknamed Jane and Petey show divergent patterns that feed an active debate over a possible species complex and the need to revise standard ageing protocols.