Birds have no teeth but that wasn’t always the case. We know that they’re descended from toothy theropod dinosaurs — in fact birds are dinosaurs — so when did they lose their teeth?

In 2014, genome sequencing studies led by Robert W. Meredith worked to determine whether several branches of birds’ ancestry lost their teeth independently (convergent evolution) or whether all birds have a common ancestor that evolved a toothless beak.

The project did full genome sequencing on 48 birds species representing nearly all modern bird orders.  They then focused their study on six genes related to tooth enamel.  All six genes became non-functional in a common bird ancestor around 116 million years ago.  That’s when birds lost their teeth.

Birds eat plenty of things that require chewing so how do they do it?  Read this 2010 blog post Anatomy: Where Are Their Teeth? to find out.

More information on the bird genome project is here in Science magazine.

(cropped image of Archaeopteryx model on display at Geneva natural history museum via Wikimedia Commons; click on the image to see the original.  **Note that this Archaeopteryx model has accurate teeth but has other inaccurate/disputed features as described on Wikimedia Commons: “Archaeopteryx had a more round shape of its wings, the primary feathers were attached to the second finger unlike here, and these colours are now known to be wrong.”)