Placoid scales, or denticles, are present in chondrichthyes like sharks, but they are often too small to be seen without magnification. These scales are felt as a rough texture, resembling sandpaper, and are oriented with their points directed toward the tail, making them retrorse projections. When touched correctly, moving from the tail to the head, they can cause abrasions similar to road rash due to their sharpness and the hard vitrodentine layer. Swimmers have reported injuries from improper handling of sharks, emphasizing the need for caution. For better observation, using a magnifier can help in identifying these scales on preserved specimens. Shark skin is also noted for its durability, with applications in food preparation, such as graters.
