Buzz
Out of approximately 43,000 living snail species, three have emerged as invasive nuisances in regions like China, Colombia, India, Barbados, and Hawaii. These species—Achatina achatina, Archachatina marginata, and Lissachatina fulica (also known as Achatina fulica)—are collectively referred to as giant African land snails. Originating in East Africa, these snails can wreak havoc when introduced to non-native environments. Here’s a closer look at these remarkable mollusks.
1. The shells of giant African land snails can grow as large as a human fist.
Featuring a whorled, striped, and predominantly brown appearance, these shells can reach lengths of up to 8 inches and diameters of nearly 5 inches. As noted by the USDA’s Animal and Plant Health Inspection Service, this is roughly equivalent to the size of an average adult’s clenched fist.
2. Unwitting pet enthusiasts played a role in the global spread of giant African land snails.
India’s struggle with land snail infestations dates back to 1847. Some of the earliest snails likely arrived as stowaways on timber shipments. Others were introduced by exotic pet enthusiasts; for instance, a blacksmith who allegedly kept L. fulica as pets may have facilitated their invasion of Bihar during the 1960s.
Giant African land snails reached Florida in 1966 after a boy brought three of them back from Hawaii, where they were already invasive. His grandmother eventually released them into the wild.
3. Invasive giant African land snails pose a significant threat to agriculture.
These snails consume a wide range of crops, including peanuts, cucumbers, cocoa, and peas. Their diet spans more than 500 plant species, encompassing lichens, algae, and fungi.
4. Giant African land snails also consume stucco and concrete.
While primarily herbivorous, giant African land snails require a constant intake of calcium for shell growth. To meet this need, they consume bones, eggshells, oyster shells, and even the shells of other snails. They are also known to gnaw on human-made calcium-rich materials such as stucco, concrete, and paint, much to the dismay of property owners.
5. Giant African land snails can host harmful parasites.
The rat lungworm (Angiostrongylus cantonensis) relies on snails to complete its life cycle. Adult worms reside and reproduce in common rat species, such as black, brown, and cotton rats. The larvae are excreted in the rat’s feces, which are then consumed by snails. If a rodent eats an infected snail, the cycle repeats.
A 2015 study of 50 L. fulica snails collected in Miami revealed that 18 of them carried rat lungworms. These parasites can cause eosinophilic meningitis in humans who consume the snails, either intentionally or accidentally through contaminated produce. The disease can be life-threatening.
6. Giant African land snails possess both male and female reproductive traits.
These snails are equipped with both reproductive organs and are highly fertile. A single mating session can result in the fertilization of multiple egg clutches over time. With each snail capable of laying up to 1200 eggs annually, they can rapidly dominate an ecosystem.
7. Giant African land snails can cause tire punctures.
Driving over these creatures can be hazardous. Their hard, jagged shells have the potential to puncture car tires or become dangerous projectiles if accidentally run over by a lawnmower.
8. Eradicating giant African land snails in Florida required seven years and $1 million …
After their accidental arrival in 1966, giant African land snails rapidly overran southern Florida. The state invested over $1 million and inspected nearly a million properties to locate and eradicate them. The campaign succeeded: within seven years, more than 18,000 snails were eliminated. By 1975, Florida’s Department of Agriculture and Consumer Services confirmed the complete eradication of the invasive snails [PDF].
9. … However, the giant African land snails made a comeback in Florida.
The snails reappeared in 2011, likely introduced through an illegal shipment for religious use. They were first spotted in Miami-Dade County and later spread to Broward County. This time, the state spent over $24 million to eliminate them, with no new sightings reported since 2017. In October 2021, the state’s agriculture commissioner once again declared them eradicated.
10. Specially trained dogs played a key role in locating giant African land snails.
The USDA employed Labrador retrievers to detect the invasive snails. Some dogs located hundreds of snails weekly. With their help, Florida officials removed more than 168,000 snails during the most recent eradication effort.
