Turtle Shells Evolved as Burrowing Tools
When a turtle is threatened it draws up into its impenetrable fortress and waits the danger out. That’s what you probably think of as the sole purpose of the turtle shell, protection.
According to a new study conducted by an international group of paleontologists, the first goal of the adaptation of the broad ribbed proto shell was for burrowing.
“Why the turtle shell evolved is a very Dr. Seuss-like question and the answer seems pretty obvious — it was for protection,” said Dr. Tyler Lyson, of the Denver museum of Nature and Science, and lead author of Fossorial Origin of the Turtle Shell, rectently published in the journal, Current Biology. “But just like the bird feather did not initially evolve for flight, the earliest beginnings of the turtle shell was not for protection but rather for digging underground to escape the harsh South African environment where these early proto turtles lived.”
The adaptation began with a distinct broadening of the ribs. “The ribs of whales, snakes, dinosaurs, humans, and pretty much all other animals look the same. Turtles are the one exception, where they are highly modified to form the majority of the shell.” Said Dr.Lyson. This broadening significantly impacted their ability to breath and the length of stride it could take, which is why the modern turtle is so slow.
