Which animal is thought to be the closest living relative to birds?

Crocodiles are the closest living relatives of the birds, sharing a common ancestor that lived around 240 million years ago and also gave rise to the dinosaurs. A new study of crocodilian genomes led by scientists at UC Santa Cruz reveals an exceptionally slow rate of genome evolution in the crocodilians (a group that includes crocodiles, caimans, alligators, and gharials).

The UC Santa Cruz team used the crocodilian genomes, combined with newly published bird genomes, to reconstruct a partial genome of the common ancestor of crocodiles, birds, and dinosaurs.