Analyses of fossilized skeletons support the hypothesis that the closest reptilian relatives of bird were the theropods,a group of relatively smll,bipedal carnivorous dinosaurs.Most researchers agree that the ancestor of bird was a feathered theropod.however,some scientists place the origin of birds much earlier,from an ancestor common to both birds and dinosaurs.the intense current interest inthe origin of birds will undoubtedly bring us closer to understanding how these masters of the sky evolved from nonflying reptiles.