According to a new study from the University of Oxford, the reduction in the size of the body of the dinosaur group that later became birds they could have helped them continue to exploit new ecological niches in the course of their evolution, in order to achieve success. The research 'was published in the journal PLOS Biology. Scientists have estimated body mass of 426 species of dinosaur in the thickness of their bones of the legs. The team found that dinosaurs have shown rapid rates of evolution of body size shortly after their origins, about 220 million years ago. However, this soon and 'slowed down: only the evolutionary line that would then lead to the birds continued to change the size of the body with this step, and continued to do so for 170 million years, producing new diversity' ecological and not ' It never has been seen in other dinosaurs. The small size of the body, according to scientists, may have been the key to maintaining the evolutionary potential in birds.