Researchers have discovered a dinosaur's characteristic to be similar to one of a human being's.
The Australian Associated Press reported that experts have analyzed 100-million-year-old bones showed a dinosaur named the "Psittacosaurus" crawled on four legs as an infant and graduated to two legs.
As a baby, the Psittacosaurus, also known as "the parrot dinosaur," had long arms and short legs because, in its first three years of life, its arms grew rapidly. At age four, the Psittacosaurus' legs went through a growth spurt, while the development of their arms slowed.
As it got older, the Psittacosaurus' legs became twice the length of its arms and eventually grew to walk on its hind feet instead of on all fours.
"Some of the bones from baby Psittacosaurus were only a few millimeters across, so I had to handle them extremely carefully to be able to make useful bone sections," Dr. Qi Zhao told the AAP. "I also had to be sure to cause as little damage to these valuable specimens as possible."
Zhao, from the Institute for Vertebrate Paleontology in Beijing, conducted the study for his PhD thesis paper at the University of Bristol. He and his team examined the bones of infant, juvenile and adult Psittacosauruses.
"This remarkable study, the first of its kind, shows how much information is locked in the bones of dinosaurs," Zhao's thesis instructor Xing Xu, of the Beijing Institute, said. "We are delighted the study worked so well, and see many ways to use the new methods to understand even more about the astonishing lives of the dinosaurs."
The Psittacosaurus was believed to have been native to Eastern Asia and lived during the crustaceous period.
Zhao performed intricate section work, studying bone sections from the dinosaur's arms and legs, at a special laboratory in Bonn, Germany. His paper will be published on Friday in the journal Nature Communications.
"These kinds of studies can also throw light on the evolution of a dinosaur like Psittacosaurus," the University of Bristol's Mike Benton, who also supervised Dr. Zhao's thesis paper, said. "Having four-legged babies and juveniles suggests that at some time in their ancestry, both juveniles and adults were also four-legged, and Psittacosaurus and dinosaurs in general became secondarily bipedal."
