The common name, “banana slug,” describes eight species of terrestrial slugs found in damp, temperate, coniferous forests along the west coast, from California to Alaska. Isolated populations occur along the coast as far south as San Diego County, and also on some moist western slopes of the Sierras. California, especially the Santa Cruz Mountains, is a species hot spot.

Often bright yellow, banana slugs can resemble their namesake fruit in various stages of ripeness or decay, shading from white to greenish browns and almost black. The Pacific banana slug (A. columbianus), which is sometimes spotty, is the most widespread, and is found outside California. Edgewood’s denizens could be one of two other species, A. californicus, or A. dolichophallus.

Slugs and snails are gastropods (“stomach-foot”), probably the largest class within the very large and diverse phylum of Mollusca. Technically, “slug” refers only to a body type, not to a closely related animal grouping, because slugs evolved from snails multiple times, in different lineages. That means a sluggy body must offer advantages.