The lower jaws of lizards, birds, fish and even dinosaurs are comprised of multiple bones per side. Yet mammals diverged from all other vertebrates and settled on just one bone, repurposing the extra ...

From the 20-foot-long jawbones of the filter-feeding blue whale to the short, but bone-crushing, jaws of the hyena and the delicate chin bones of a human, the pair of lower jawbones characteristic of ...

A random selection of lower jaw shapes from among the world's vertebrate animals. All are mammal jaws consisting of a single bone except for those in orange, which are from vertebrates that have lower ...