Slugs, snails and worms are all creatures without a backbone. These creatures are called invertebrates. Other invertebrates in Girraween include the insects, millipedes and centipedes, spiders and scorpions, and crayfish.

Slugs and snails are closely related, both being gastropod mollusks. Snails all have shells that they can retract into, while slugs may only have a shell that's too small to hide in and many have no shell at all. Some live on land and others live in water.

There are many different types of worms. They include annelids (earthworms), nematodes (roundworms), and platyhelminthes (flatworms). Often overlooked, these creatures play an important role in the environment and, in Girraween, this is no exception.