Fun Facts!
1. Skin denticles are teeth-like scales that cover the body of rays, skates, and sharks.
2. In modern sharks and rays, the skin denticles all point toward the tail. This causes the skin to feel smooth in one direction and rough like sandpaper in the other, which helps them swim faster.
3. The placoid scales of sharks and rays do not grow bigger as the fish grows bigger. Instead, new scales are created in between the old ones to cover the animal’s increased body size.