> "Why would a large dinosaur evolve a beak and lose the efficiency of teeth?" That's a good question. I'm just an amateur, but I can guess at a few reasons.

> "Why would a large dinosaur evolve a beak and lose the efficiency of teeth?" That's a good question. I'm just an amateur, but I can guess at a few reasons. 1) Diet was not hampered by having either beak or teeth and a beak requires less maintenance (no tooth decay) and energy to grow. Beaks can also be more equipped to open seed shells and other barriers to food than teeth. I'm always quite amazed at the way finches are able to pop the seed out of a tiny thistle seed at a rapid pace. 2) Birds use their beak and legs as "radiators" to help regulate their internal temperature[1]. May have helped this species to better adapt to its area than others. [1] http://www.audubon.org/news/how-birds-keep-their-cool http://www.audubon.org/news/how-birds-keep-their-cool