Scientists have determined that Neandertals had big mouths that they were able to open unusually wide. No great surprise given their large craniums and strong facial musculature, but what is more interesting is that we have now sequenced their DNA and determined that they did not interbreed with modern homeo sapien sapiens.

Do you suppose Neanderthals died out because of some lack of evolutionary skill or perhaps their small, inbred population with a sea of genetic mutations and mouths gaped widely meant the cooler kids, the homo sapien hipsters, just wouldn't play nice, hang out and interbreed>.