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The 'Banana slug' is any species of the pulmonate gastropod genus, '''Ariolimax''', (literally, "Arion's slug"), although when used in the context of a species banana slug usually refers to the 'Pacific banana slug' (''Ariolimax columbianus''). Banana slugs are usually bright yellow (somewhat resembling a banana) although they may also be green, brown, or white. The Pacific banana slug is the second-largest species of terrestrial slug in the world, growing up to 25cm (9.8 inches) long (the largest is ''Limax cinereoniger'' of Europe, which can reach 30 cm (12 inches) in length).
It is native to the forest floors along North America's Pacific Coastal coniferous rainforest belt (including redwood forests) which stretches from Southeastern Alaska to Central California, just south of the San Francisco Bay Area. Scattered, isolated populations do occur in the coastal and traverse mountain ranges to the south of Santa Cruz with the southernmost population located in the Palomar Mountain Range in San Diego County, California with its lush Sierra Nevada-like coniferous forests. Isolated populations also occur as far inland as the Columbia Mountains in British Columbia with temperate coniferous rainforests similar to those of the Pacific Northwest, and in the Sierra Nevada mountains to the north of Yosemite National Park in California.
Banana slugs are detritivores. They process leaves, animal droppings, and dead plant material, and then recycle them into soil. They seem to have a fondness for mushrooms, and they spread seeds and spores when they eat. They move relatively slowly since banana slugs, like all slugs, have only one muscular foot.
Slugs use two pairs of tentacles to sense their environment. The larger, upper pair, termed "eyestalks," is used to detect light or movement. The second, lower pair is used to detect pheromones. The tentacles can retract and extend themselves to avoid damage from leaves and twigs.
Banana slugs have a single lung which opens externally with a pneumostome. The pneumostome holds air which is passed through the lung cavity. Banana slugs excrete a thick coating of slime around their bodies. The slime keeps the skin moist, so the slug can breathe through it. If the skin is not moist, the slug cannot exchange gases. The slime gathers moisture from the air on damp days, and from soil beneath logs on dry days. To prevent themselves from drying out, slugs can also estivate: they secrete a protective layer of mucus, and insulate themselves with a layer of soil and leaves. They remain inactive in this state until the environment is moist again.
The coating offers other protections as well. It allows slugs to travel unharmed across the sharp edge of a razor blade or piece of glass, and can thwart predators; the slug excretes thick mucus and humps its body up, making itself appear larger. When the slime comes into contact with a moist surface, it produces an anasthetic which causes the membranes to go numb.
The slime of the banana slug also lubricates the terrain over which they move, so they can travel more easily. When climbing a tree, a slug can drop back down quickly using a string of slime. Researchers have made unsuccessful attempts to reproduce slug slime, since it is one of the best natural glues, and has potential uses in medicine.
The slime also contains pheromones to attract other slugs for mating. Slugs are hermaphrodites, and reproduce by exchanging sperm with their mate. They produce up to twenty translucent eggs, which are laid in a log or on leaves. Slugs mate and lay eggs throughout the year. The adults provide no further care for their eggs beyond finding a suitable hiding spot, and the eggs are abandoned as soon as the clutch is laid.
Raccoons, garter snakes, ducks, geese and salamanders sometimes eat banana slugs, but they roll the slugs in the dirt to bind up the slime. Baby banana slugs are sometimes eaten by shrews or moles.
Salt is harmful to all slugs; it causes the slug to dehydrate. Blood rushes to the surface of the skin to dilute the salt. This process is only effective with small quantities of salt.
The banana slug is the official mascot of the University of California, Santa Cruz.
''Ariolimax dolichophallus'', a species of banana slug (dolichophallus meaning "long penis" in Latin) has the largest penis-to-body length ratio of any animal. The record-holding specimen had a body length of 6 inches, with a phallus length of 32.5 inches, well over five times the body length.

Contents

Species

Gallery

Species

★ California Banana Slug, ''Ariolimax californicus''

★ Pacific Banana Slug, ''Ariolimax columbianus''

★ Slender Banana Slug, ''Ariolimax dolichophallus''

Gallery