Birds' Time To Sexual Maturity Found To Be Cause Divergence From Dinosaurs

It is a known fact that the closest living relatives to the dinosaurs are birds. While hard to believe, a chicken and a Tyrannosaurus Rex are closer cousins than a Tyrannosaurus Rex and a crocodile. New research has shed some light on this strange phenomena, and it seems that the amount of time that birds take to reach sexual maturity was a key evolutionary difference.

"What is interesting about this research is the way it illustrates evolution as a developmental phenomenon," said Arkhat Abzhanov, Associate Professor of Organismic and Evolutionary Biology and one of the paper's authors. "By changing the developmental biology in early species, nature has produced the modern bird - an entirely new creature - and one that, with approximately 10,000 species, is today the most successful group of land vertebrates on the planet."

Birds can take as little as 12 weeks to mature unlike dinosaurs, which take much longer. The shorter time span means less time for drastic physical development. This means that birds retain characteristics similar to baby dinosaurs.

"The evolution of the many characteristics of birds - things like feathers, flight, and wishbones - has traditionally been a difficult problem for biologists," Mark Norell, chair of the Division of Paleontology at the American Museum of Natural History and one of the paper's co-authors, said. "By analyzing fossil evidence from skeletons, eggs, and soft tissue of bird-like dinosaurs and primitive birds, we've learned that birds are living theropod dinosaurs, a group of carnivorous animals that include Velociraptor. This new work advances our knowledge by providing a powerful example of how developmental changes played a major role in the origin and evolution of birds."

Bird skulls show that birds have proportionally larger eyes and brains than an adult dinosaur's skull, which has a longer snout and teeth.

"In the case of birds, we can see that the adults of a species look increasingly like the juveniles of their ancestors."

A chicken being a sexually premature Tyrannosaurus Rex? Strange, but apparently true.