Land Snails

Achatinids are generally nocturnal forest dwellers but have the potential to adapt to disturbed habitats. Concealed habitats are generally preferred; however, individuals may colonize more open habitats in the event of overcrowding. Achatinids often become more active during periods of high humidity (e.g., after rainfall); however, the occurrence of large numbers of individuals especially during daylight may indicate high population density.

Achatinids normally lay their calcareous eggs in the soil, but they may be deposited under leaf litter or rocks. They feed on both living and dead plant material. In addition to being agricultural pests, achatinids can be a threat to public health as they act as a reservoir host of the rat lung parasites (Angiostrongylus cantonensis and A. costaricensis), which cause eosinophilic meningoencephalitis in humans. They can also be an unsightly public nuisance during periods of population explosion.

The body of the live animal has two pairs of tentacles, one short lower pair that are tactile and chemotactic, and one longer upper pair with eye spots at the tips. The body itself is moist, slimy and rubbery. Body coloration can be either mottled brown or more rarely a pale cream color. The footsole is flat, with coarse tubercles most evident laterally on the upper surface of the extended body.

The outline of the shell may vary somewhat, even within the same colony, from slender to moderately obese. The broader specimens with the same number of whorls tend to be shorter in shell length. The shell is generally conically spired and distinctly narrowed but barely drawn out at the apex. The whorls are rounded with moderately impressed sutures between the whorls. The aperture is relatively short and has an ovate-lunate shape. The lip is sharp, convex, thin and evenly curved into a regular semi-ellipse. The shell surface is relatively smooth, with faint axial growth lines.

One of the most important identification features of Achatina fulica is the columella which truncates or ends abruptly, a feature remaining evident throughout the lifespan of the snail. The columella is generally concave; lesser concaved columella tend to be somewhat twisted. The broader shells tend to have a more concave columella. The columella and the parietal callus are white or bluish-white with no trace of pink."