What are reptile scales primarily made from?

Reptile scales are primarily made from keratin, which is a fibrous structural protein. Keratin is a key component in the formation of various protective structures in animals, including scales, feathers, hair, and claws. In reptiles, the scales provide vital protection against environmental factors, prevent water loss, and aid in thermoregulation. The unique properties of keratin allow reptile scales to be tough yet flexible, enabling reptiles to thrive in diverse habitats.

Other materials like collagen and chitin do contribute to structures in various organisms but are not the primary components in the formation of reptile scales. Calcium carbonate, while important in the shells of some other animals, does not play a significant role in reptile scales. Thus, keratin is the definitive answer for the composition of reptile scales.