Archachatina Marginata popularly known by its abbreviation of “AM” characterized by (big black snail, giant African land snail) is a large snail, generally growing to about 20 cm and a live weight of 500g. The shell is much less pointed than the Achatina species, the roundness being especially obvious in young animals.
Striation on the shell maygive the appearance of a ‘woven’ texture. The head of the snail is dark-grey itsfoot is a lighter shade. This species has been the object of a series ofstocking and feeding experiments in Nigeria for instance.
Archachatina Marginata isnative to the humid African rainforest belt, from Southern Nigeria to Congo,but is now found in other parts of the African rainforest zone.
Using Nigerian experiments asa case study, juvenile growth was found to be inversely proportional totemperature, falling sharply at temperatures > 30 °C, and directlyproportional to rainfall and humidity. Body weight gain slows downsignificantly during the dry season (December to March in Southern Nigeria,where the breeding trials took place).
Reproduction: The species reaches sexual maturity at an age of around one year, when the individuals reach a live weight of 100-125 g. Reciprocal copulation must occur to produce viable eggs.
Laying eggs: The eggs are comparatively large at 17 × 12 mm, with an average weight of 4.8 g in a Nigerian stocking trial. For that reason, the number of eggs per clutch is low, 4-18 eggs. Eggs are laid in the soil at a depth of about 10 cm.
Hatchlings: Theincubation period from egg to hatchling is around 4 weeks. Hatchlings have athin, transparent shell; they generally remain in the soil for 5 to 7 daysbefore emerging, but sometimes wait even longer. Because of the relatively highweight of the eggs the number of hatchlings from a clutch is low compared tothe other two species. During the first weeks after emerging, hatchlingsrepeatedly burrow into the soil.
Juveniles: In laboratory trials shell length of the juvenile snails increased by an average of 0.33 mm/day for the first 8 months (c. 8 cm), slowing down to 0.2 mm/day at 15 months. Shell length hardly increases after that time.
Adults: The snails reach sexual maturity at around 10-12 months (Plummer, 1975).