Slugs have 4 noses.
Slugs actually have two tentacles on the front of their sluggish bodies that they use to smell things.
A slug also has two larger tentacles that are topped with the tiny, sluggy eyeballs. The slug uses them to observe the slimy path of destruction as it ever-so-slowly goes through a garden.
The fact that a slug has four tentacles that perform sensory functions may have lead to the oft-repeated — but totally erroneous — factoid that “a slug has four noses.” But first of all, a slug has NO noses, and secondly, it only uses two of the four tentacles to smell.