Banana slug is the common name for three species of air-breathing land slugs that are often yellow in colour and sometimes spotted with brown like an overripe banana.
Banana slugs are gastropods, a class whose named species are second only to insects in overall number. The fossil history of this class goes back to the Late Cambrian (500 million years ago). There are 611 families of gastropods, of which 202 families are extinct and appear only in the fossil record.
Banana slugs grow six to ten inches in length – making them the second-largest slug in the world –and they can live for as long as seven years. Named for their roughly cylindrical shape and characteristic golden yellow colour, banana slugs also come in other colours, including greenish-brown, nearly black, and white.
The less common colours reflect the influence of diet, available light, moisture, age, health, and other factors. But the basic coloration evolved to blend with detritus and to avoid detection by salamanders, garter snakes, raccoons, foxes, porcupines, crows, ducks, beetles, and other predators.
Banana slugs have a slimy mucus coating that helps them to avoid dehydration, to slide along the ground on a muscular foot that covers its lower body, and to protect the animal’s soft body from sharp rocks, twigs, and other hazards. The slime also discourages predators with its foul taste and mouth-numbing anaesthetic effects.
Even so, banana slugs have been used as food by Yurok Indians of the North Coast and by German immigrants in the 19th and early 20th centuries. A yearly festival and contest is held at Russian River (California) including slug races and a contest for recipes.
But even when fed corn meal to purge them or soaked in vinegar to remove the slime, the slugs’ flavour is not highly regarded, and the most successful recipes are often those in which the taste is unnoticeable. Banana slug sushi anyone?