The giant African land snail, is the largest species of snail found on land and generally grow to around 20 cm in length. The giant African land snail is native to the forest areas of East Africa but has been introduced into Asia, the Caribbean and a number of islands in both the Pacific and the Indian oceans.
The giant African land snail is generally seen as a pest as these snails will eat almost anything vegetarian that they can find and have proven to be quite destructive when around crops and wild flowers. Giant African land snails are also known to carry parasites and are illegal to keep as pets in some countries such as the USA.
The giant African land snail (Achatina fulica) is a threat to the sustainability of crop systems and native ecosystems, having a variety of negative impacts on native fauna, from competition for resources to the spread of diseases to direct herbivory of native plants. Native snails in fragile island ecosystems such as Hawaii and the French Polynesian islands are particularly susceptible to the negative effects of A. fulica and other introduced snails. The best way to prevent the further spread of A. fulica is by strengthening international quarantine systems.
Suggested preventative measures must include strict quarantine measures to prevent introduction and further spread. Many methods have been tried to eradicate the Giant East African Snail. Generally, none of them have been effective except where implemented at the first sign of infestation. Methods include hand collecting, use of molluscicides, flame-throwers, and the failed attempts at biological control discussed below. In some regions, an effort has been made to promote use of the Giant East African Snail as a food resource, collecting the snails for food being seen as a method of controlling them. However, promoting a pest in this way is a controversial measure, as it may encourage the further deliberate spread of the snails.
One particularly catastrophic attempt to biologically control this species occurred on South Pacific Islands. Colonies of A. fulica were originally introduced as a food reserve for American GI's during the second world war, but naturally escaped. A carnivorous species from East Africa, a known predator of the East African Land Snail was introduced, but instead heavily predated the native Partula, causing the loss of some species.
The giant African land snail is native to humid, forest areas but can today be found in agricultural areas, coast land, natural forest, planted forests, shrublands, urban areas, and wetlands. The giant African land snail is seen to be highly invasive species and large colonies of land snails can be formed from just one individual.
Giant African land snails have both male and female reproductive organs. Although giant African land snails primarily mate with one another, in more isolated regions the giant African land snail is capable of reproducing by itself. Giant African land snail lay around 6 clutches of eggs every year, laying an average of 200 eggs per clutch. Around 90% of snail hatchings survive meaning that a snail free area can quickly become infested.
Giant African land snails are active during the night and spend the daytime hours safely buried underground. Giant African land snails reach their adult size by the time they are 6 months old and although their growth rate slows at this point, giant African land snails never stop growing. Most giant African land snail reach between 5 and 6 years of age but some giant African land snail individuals have been known to be more than 10 years old.
During periods of extreme drought, the giant African land snail goes into aestivation (summer sleep). The giant African land snail seals itself inside it's shell to retain water and giant African land snails do this about 3 times a year, depending on the areas in which they inhabit.