At Least Some Dinosaurs Had Belly Buttons, Exquisite Fossil Just Revealed
The oldest 'belly button' known to science has been found on an exquisitely preserved horned dinosaur fossil from China.The slit-like scar comes not from an umbilical cord, as it does in mammals, but from the yolk sac of the egg-laying creature that lived about 130 million years ago.
Today, many living snakes and birds lose their so-called umbilical scar within days or weeks of an egg hatching. Others, like adult alligators, keep them for life.
This is a picture of an American alligator belly button (umbilical scar.)…