18 nov 2011
Arctic life was tough on dinosaurs, with many not making it to their 20th birthday.
- By counting tree-like bands on femur fossils, paleontologists can estimate dinosaur growth stages.
- Some North Pole dinosaurs grew fast as juveniles, became sexually mature at age 9, and died at around 19.
- Northern Alaska during the latter Dinosaur Age was slightly warmer than it is now, but still experienced freezing temperatures during long, dark winters.
The findings, published in the journal Historical Biology, offer a rare look at dinosaur life stages. Fossils from high latitudes better express growth bands that reveal how these animals grew up. Scientists can then analyze them similar to how they study tree rings.
