Turtle shells are made of the same material as what human body part?

We may recall from grade school that the human body is 60% water, but we also have a whole lot of keratin. Keratin is a fibrous protein, found in animals, like the scutes of the turtle's shell, and humans, that produce a lot of specialized tissues, including the ones that produce hair.

But all keratin is not the same. One type, α-keratin, produce hair, wool, nails, hooves, claws, and horns. The other type of keratin, β-keratin, is more for our scaly and feathered friends. You can find β-keratins in tortoise shells, scales of reptiles, reptile nails, bird claws, feathers, porcupine quills, and bird beaks.

The word keratin comes from the Greek word for horn. This protein is rich in sulfur and is also found in our fingers and toenails.