Snails Have Thousands of Teeth

While a garden snail might seem soft and harmless, its mouth conceals a formidable feeding apparatus. Instead of a jaw, it possesses a unique structure called a radula, a flexible, ribbon-like tongue (Review) covered in thousands of microscopic teeth. Arranged in neat rows, these teeth, numbering up to 20,000 in some species, act like a tiny file or rasp. As the snail moves its radula back and forth, it scrapes and shreds food particles from surfaces, pulling the resulting pulp into its digestive system. This allows it to consume not just soft leaves but also tougher plant matter, algae, and even soil to obtain essential minerals.

This remarkable feeding tool works like a biological conveyor belt. The teeth, composed primarily of chitin (the same material found in insect exoskeletons), are constantly subjected to wear and tear as the snail eats. To solve this problem, new rows of teeth are continuously grown at the back of the radula. As the older, worn-down teeth at the front break off, the newer, sharper teeth from behind move forward to take their place. This system of constant replacement ensures the snail has a sharp, effective feeding tool throughout its entire life, a perfect adaptation for its slow but steady foraging.