Dinosaurs—they grow up so fast, especially if they’re trying not to get eaten.
Hypacrosaurus, a duck-billed dinosaur that could reach more than 30 feet in length, was a preferred meal of the Tyrannosaurus Rex. But this prey dinosaur had a trick to keep the species alive—Hypacrosaurus grew to adulthood remarkably quickly, according to a new study in the Proceedings of the Royal Society B [pdf]. The research suggests that it took 10 to 12 years for Hypacrosaurus to become fully grown. Tyrannosaurs, however, reached adulthood after 20 to 30 years, said Drew Lee, a postdoctoral fellow in Ohio University’s College of Osteopathic Medicine who co-authored the paper [Science Daily].
The Hypacrosaurus’ accelerated growth rate allowed it to reach sexual maturity at only two or three years old, giving it the chance to reproduce before predators gobbled it up, according to study co-author Lisa Noelle Cooper. “That’s another added bonus when facing predators—if you can keep reproducing, you’re set, it’s the stuff of evolution,” said Cooper [AFP].
But how can researchers tell the rate at which a long-dead dinosaur grew? The scientists found that, during the fossilization process, the shape of bone cells and, “more importantly, growth rings” are preserved. Similar to calculating the age of a tree, the researchers then counted the growth rings to determine the dinosaur’s growth rate [Discovery Channel].
Unfortunately for Hypacrosaurus, its evolution seems to have produced no other major defenses against predators, like the Stegosaurus’ armor and spikes. So after the duck-bill grew up and reproduced, there’s a good chance that at some time or another, it was another dinosaur’s dinner.
Image: Drew Lee/Ohio University