If you’re a mollusc, you’re a part of a very large phylum of creatures, including squids, clams and octopuses. And if you’re a slug or a snail, and you cruise around on your belly and leave a trail, then you’re a gastropod too–gastropod is Greek for “stomach foot”. And since you’re cruising around on your belly, you’ll benefit from some slime. Slugs and snails produce mucin (slime) from glands to help them get around, recognize each other, stick to stuff, reproduce and other necessary gastropody tasks.
Snails, which can be recognized by the shell on their backs, can be found up mountains, under rocks, in the desert, and under water (aquatic snails) says Snail-World. If you go outside and look under a log, you’ll probably find one there (hangin’ out with roly-polies). Slugs, don’t usually have shells. If they do, they are very small ones, or have only small internal shells.
Slugs and snails do eat our plants and that’s not so nice, but they are doing some important work otherwise. They breakdown organic matter in our yards and gardens, which, in the end, becomes organic matter, which makes good fertilizer. See below for our gastropods (and their poop).
They feed a whole host of critters from birds to reptiles to rodents. Scientists have replicated the slug’s sticky yet flexible slime into a surgical glue to help repair soft tissues without damaging them, says NPR. Cosmetics companies “milk” garden snails for their mucin. The methods by which they do this are unclear, says Racked. In Japan, they just stick the slimy critters on your face and they glide around, transferring that rejuvenating sliminess right onto your skin. Wikipedia has more examples of their usefulness going back to Ancient Greece. Need a good cough syrup, go no further than your local snail.
A parting video: mating leopard slugs. I would say this is X-rated.