Most slug species, however, are much smaller. The average slug is about 1-2 inches long. Some species, such as the pygmy slug (Oxychilus cellarius), are only about 1/4 inch long.
How big can an average slug get?
Slugs can vary greatly in size, depending on the species. The largest slug species is the banana slug (Ariolimax columbianus), which can reach a length of up to 10 inches. Other large slug species include the leopard slug (Limax maximus), which can grow up to 8 inches long, and the great gray slug (Limax cinereoniger), which can reach a length of up to 6 inches.