While slugs are pretty much snails without shells, they don’t seem to be jealous of their cousins’ houses on the go.
It’s true that snails use their shells for protection—from other animals and from drying out in the sun. But that doesn’t mean slugs are helpless.
They can hide in small spaces that a snail can’t, and that protects them from predators and the sun, and even gives them a good place to lay eggs. They can escape harsh weather by burrowing into the ground during hot, dry spells and to hibernate in the winter.
Slugs live on land, in the sea and in freshwater. Many have colors that blend into the background or bright colors that warn other animals that they’re not a tasty snack. Banana slugs cover themselves in mucus that can numb a predator’s mouth.
Some researchers even suggest that slugs once had external shells, as they evolved from snails and lost their shells over time. Today, most slugs have a remnant of a shell, although it’s usually internal.
In each issue of Iowa Outdoors in But Why? we help parents answer their kids' questions about nature. This piece originally appeared in the March/April 2013 issue of Iowa Outdoors.