Page 187 - Biomimetics: Technology Imitates Nature

The snail’s drilling system is even able to rasp holes in rocks.
The snail’s tongue, called a radula, resembles a large-toothed file. Thanks to this de-
sign, the mollusk is able to rasp holes in leaves and pick up algae
on rocks.
Teeth on the radula are so hard that some desert snails are
even able to make holes in rock. (Phil Gates, Wild Technology,
45.)
The giant excavators humans use to dig tunnels perform a
similar function to the radula. However, the tips of these ma-
chines’ drills wear out and have to be frequently replaced.