The giant African land snail

Lissachatina fulica, the giant African land snail, is a very large land snail. Adults commonly exceed ten centimetres in shell length and can approach twenty, with a tall brown shell streaked in cream. The species is native to East Africa. Trade and accidental transport have carried it through much of the tropics and subtropics. Where it establishes, it can damage crops, strip garden plants, and crowd or consume native snails.

It is also one of the snails that can carry the rat lungworm, Angiostrongylus cantonensis. The parasite uses rats as its definitive host and snails as an intermediate. People are infected by eating raw or undercooked snails, or produce contaminated with the parasite. The practical rules are plain. Do not eat wild snails. Wash produce. Wash your hands after handling any snail. Do not treat a large exotic animal as a curiosity to be passed around a classroom.

Many jurisdictions prohibit keeping this species. The United States does. The rules exist because the invasion risk is documented: populations have established, and eradications have been expensive. A single fertilized hermaphrodite can start a colony. An animal offered free online, or a clutch of eggs passed off as a novelty, is a common beginning. Releasing one “back to nature” outside its range is not mercy. It is the dispersal event the rules are written to prevent.

If you find a very large achatinid where it is not native, do not move it to a park, a compost heap, or a friend’s garden. A local agricultural authority will want a photograph and a location, and will say whether they want the animal. This is a different ethic from the one that applies to a thumbnail-sized glass snail already living under your bin. Size, diet, and a history of establishment change the response.