And there's one final clue... A clue that all but definitively connects birds and dinosaurs, and it's something you'd least expect... Something scientists call the furcula. Or wishbone.
Wishbones have only been found in birds and Theropod dinosaurs, like Allosaurus, and they draw a clear line from those extinct creatures to our modern feathered friends.
And the one bone that is the biggest clue of Theropod dinosaurs is something that you've probably played a little game with after your thanksgiving dinner: The wishbone!