The Wishbone Tells

The dinosaur proof is built into every bird's skeleton. Birds have a furcula — the wishbone you pull at a holiday dinner — and so did many theropods, T. rex included. They also share hollow bones and air sacs that pump oxygen through the body more efficiently than mammal lungs. A bird's foot is not a new invention either; it is a theropod foot, slightly remodeled. These are inherited parts, not coincidences.