Researchers from the University of Southampton have made an extensive family tree of dinosaurs and their bird descendants. Through this map, researchers have mapped their transformation.

They have reached at a conclusion that massive-meat eating dinosaurs that transformed themselves into agile flying birds were able to survive as they have reduced their size over 50 million years.

From the map, researchers found out that theropod dinosaurs, which led to the rise of modern birds, were the only ones that kept on getting smaller in size. Theropods included carnivorous dinosaurs including Tyrannosaurus, Velociraptor and Spinosaurus.

"These bird ancestors' also evolved new adaptations, such as feathers, wishbones and wings, four times faster than other dinosaurs", affirmed Paleontologist Darren Naish, co-author of the study. Lead author Michael Lee, from the University of Adelaide, said that it is an exciting finding that reveals how birds have evolved. It has been quite a unique phase in which dinosaurs kept on decreasing in size.

While they kept on getting smaller in size, they also reduced weight. Along with it, they evolved anatomical adaptations, which allowed them to perform activities like ability to climb trees, glide and fly.

This evolution majorly helped birds to survive that disastrous meteorite impact that wiped out dinosaur population. To come up with the family tree, researchers have assessed more than 1,500 anatomical traits of dinosaurs. For the same, mathematical modeling was used that helped them to trace the evolving patterns, change in body size in different dinosaur branches.

Researchers concluded by saying that dinosaurs that led to birds were more innovative than other dinosaur lineages.