Duck-Billed Dinos Outgrew Predators

In addition to growing up to five times faster than the tyrannosaurs, the duck-billed dinosaur grew at least twice as fast as the relatively tiny, 6.5-foot-long Troodon. Since growth in the hadrosaur slowed after about 2.5 years, the scientists believe it reached sexual maturity at only two to three years of age.

"As long as the dinosaur was able to successfully reproduce, in an evolutionary sense, it was able to withstand predation," Cooper explained. "The whole point is to reproduce as quickly as possible -- that's the stuff of evolution."

Prior research determined that modern fish, insects and animals employ the fast maturation strategy as well to out-produce and outgrow predators. These quick growers include killifish, wildebeest, butterflies, toads, salamanders, guppies and some birds, such as penguins.

Kevin Padian, a professor of integrative biology at the University of California at Berkeley and curator of the university's Museum of Paleontology, told Discovery News that the new findings make sense.

"This growth game has been played by many prey animals for millions of years," he said, mentioning that other dinosaurs, such as ceratopsians, sauropods, and even large, carnivorous dinosaurs, like Allosaurus, appeared to evolve faster maturation and speedier growth rates to both avoid, and survive, predators.

Explaining why certain toothy meat eaters would need to evolve faster growth, Padian said, "There are so many carnivores that, no matter who you are, there's somebody out there that is ready to kill you."

In the future, Lee hopes to gather and compile specific growth rate data for other dinosaurs, in hope of learning more about dinosaur evolution and the fast growth survival strategy.

Related Links:

Discovery News blog: Born Animal

How Stuff Works: Dinosaurs

Introduction to the Hadrosaurs

Museum of the Rockies