Dinosaurian growth rates and bird origins

Nature. 2001 Jul 26;412(6845):405-8. doi: 10.1038/35086500.


Dinosaurs, like other tetrapods, grew more quickly just after hatching than later in life. However, they did not grow like most other non-avian reptiles, which grow slowly and gradually through life. Rather, microscopic analyses of the long-bone tissues show that dinosaurs grew to their adult size relatively quickly, much as large birds and mammals do today. The first birds reduced their adult body size by shortening the phase of rapid growth common to their larger theropod dinosaur relatives. These changes in timing were primarily related not to physiological differences but to differences in growth strategy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Evolution*
  • Birds* / anatomy & histology
  • Birds* / growth & development
  • Body Constitution
  • Bone and Bones / anatomy & histology
  • Reptiles / growth & development*