Dermal denticles are small, tooth-like structures found in the skin of certain fish, particularly sharks and rays. These unique features provide protection and reduce drag while swimming, allowing these animals to move more efficiently through water. Unlike scales, dermal denticles are made of a hard material called dentin and are covered by a thin layer of enamel. They vary in shape and size, contributing to the distinct texture of a shark's skin, which feels similar to sandpaper. This adaptation helps sharks thrive in their aquatic environments.