Invertebrates
Giant African Land Snail
Lissachatina fulica · also called giant African snail, GALS
The giant African land snail is one of the largest land snails in the world and one of the most destructive animals ever moved around the planet by people. A single hand-sized snail can found an infestation, chew through gardens and crops, gnaw the render off a house, and spread a parasite that attacks the human brain.
Overview
The species is native to the coastal forests of East Africa, where it is a normal part of the fauna and kept in check by predators, parasites, and climate. Everywhere else it has become a serious invasive pest — it is established across tropical Asia, the Pacific islands, the Caribbean, and parts of South America, and it has been introduced to Florida at least twice and eradicated at enormous cost each time. It thrives in warm, humid conditions, in forest, farmland, gardens, and urban areas alike.
Why it spreads so well
- Diet: it eats more than 500 species of plant, including nearly every crop and garden plant, and rasps calcium from limestone, plaster, paint, stucco, and bones.
- Reproduction: every snail is a hermaphrodite; a pair can each lay eggs after mating, a lone snail can sometimes self-fertilise, sperm can be stored for years, and one animal produces around 1,200 eggs a year.
- Resilience: in drought or cold it seals its shell with a mucus door (aestivation or hibernation) and survives for months, then resumes activity when conditions improve.
- Transport: it hitchhikes in shipping containers, plant and soil imports, machinery, and vehicles, and is carried deliberately as a pet, food, and traditional-medicine item.
The health hazard
Giant African land snails are a known carrier of the rat lungworm (Angiostrongylus cantonensis), a parasite whose larvae they pick up from rat droppings. In humans the parasite causes eosinophilic meningitis, contracted by ingesting infected snails or slugs — sometimes accidentally through contaminated produce, water, or hands. This makes the snails not just an agricultural problem but a public-health one.
Control
Because the snail is so hard to eliminate, response programmes focus on early detection and rapid, total eradication of new populations: hand collection, targeted molluscicide baiting, quarantine of infested areas, restrictions on moving plants and soil, and public reporting campaigns. Florida’s most recent eradication effort ran for years and removed millions of snails before the state was declared clear again.
Status
In conservation terms the giant African land snail is Least Concern — abundant and expanding. Its listing among the “100 of the world’s worst invasive species” reflects its impact on agriculture, native snails and plants, buildings, and human health wherever it is not native.
Giant African Land Snail: common questions
Why is the giant African land snail such a bad invasive species?
It combines almost every trait that makes a pest hard to stop. It eats over 500 kinds of plant, including most crops and ornamental species. It is a hermaphrodite, so any two snails — or in some cases a lone snail — can breed, and one animal produces well over a thousand eggs a year. It can go dormant for months to survive bad conditions and then revive. It has few natural enemies outside Africa, and it spreads easily as a stowaway in cargo, plant shipments, and vehicles, and deliberately as a pet, food, and folk-medicine item. Florida has had to mount two separate multi-year, multi-million-dollar eradication campaigns.
Is it dangerous to touch a giant African land snail?
Handling one is not automatically harmful, but there is a real risk. The snails can carry the larvae of the rat lungworm parasite in their slime and tissues, and swallowing them — even accidentally, via unwashed hands, produce, or water contaminated with snail mucus — can cause eosinophilic meningitis, a serious and occasionally fatal inflammation of the brain lining. Anyone who handles the snails should wash thoroughly and not let children play with them.
Why does it eat concrete and stucco?
For calcium. A snail this large needs a great deal of calcium carbonate to build and maintain its heavy shell, and where soil calcium is low it will rasp at limestone, plaster, painted walls, stucco, sidewalks, and even the bones and shells of dead animals to get it. In Florida infestations, damage to house exteriors is one of the more visible signs.
Are giant African land snails kept as pets?
They are, in parts of Europe and elsewhere, because they are large, long-lived, and easy to feed. But keeping or importing them is illegal in the United States and many other countries precisely because escaped or released pets are a primary route of invasion. The species has repeatedly established in new areas after being brought in as a novelty pet or a classroom animal.