Turtles have roamed the Earth since the Triassic Period over 200 million years ago. A new study about their evolution, published in iScience, shows how the scales on turtles’ heads can teach us more about their dinosaur ancestors and their living relatives like crocodiles and birds.
For most vertebrates, genetics control where and how they grow things like feathers, hair, and scales. Crocodiles are an exception to this rule, as their scales form thanks to mechanical processes like skin folding. Researchers have now discovered another exception to the rule, as turtles are the only vertebrates that combine these two processes — genetic and mechanical — to create the scales on their heads.
