Achatina achatina, common name the giant Ghana snail, also known as the giant tiger land snail, is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of very large, air-breathing land snail

Snail

Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

, or more technically a terrestrial

Terrestrial animal

Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...

 pulmonate gastropod mollusk in the family Achatinidae

Achatinidae

Achatinidae is a family of medium to large sized tropical land snails, terrestrial pulmonate gastropod mollusks from Africa...

. The name 'Achatina' is from 'achates', Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 for agate

Agate

Agate is a microcrystalline variety of silica, chiefly chalcedony, characterised by its fineness of grain and brightness of color. Although agates may be found in various kinds of rock, they are classically associated with volcanic rocks and can be common in certain metamorphic rocks.-Etymology...

.

Distribution

The species is believed to be native to West Africa, within 100–190 miles of the coasts of Sierra Leone

Sierra Leone

Sierra Leone , officially the Republic of Sierra Leone, is a country in West Africa. It is bordered by Guinea to the north and east, Liberia to the southeast, and the Atlantic Ocean to the west and southwest. Sierra Leone covers a total area of and has an estimated population between 5.4 and 6.4...

, Liberia

Liberia

Liberia , officially the Republic of Liberia, is a country in West Africa. It is bordered by Sierra Leone on the west, Guinea on the north and Côte d'Ivoire on the east. Liberia's coastline is composed of mostly mangrove forests while the more sparsely populated inland consists of forests that open...

, Ivory Coast, Togo

Togo

Togo, officially the Togolese Republic , is a country in West Africa bordered by Ghana to the west, Benin to the east and Burkina Faso to the north. It extends south to the Gulf of Guinea, on which the capital Lomé is located. Togo covers an area of approximately with a population of approximately...

, Benin

Benin

Benin , officially the Republic of Benin, is a country in West Africa. It borders Togo to the west, Nigeria to the east and Burkina Faso and Niger to the north. Its small southern coastline on the Bight of Benin is where a majority of the population is located...

, Ghana

Ghana

Ghana , officially the Republic of Ghana, is a country located in West Africa. It is bordered by Côte d'Ivoire to the west, Burkina Faso to the north, Togo to the east, and the Gulf of Guinea to the south...

, and Nigeria

Nigeria

Nigeria , officially the Federal Republic of Nigeria, is a federal constitutional republic comprising 36 states and its Federal Capital Territory, Abuja. The country is located in West Africa and shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in...

.

Achatina achatina has as yet not been found outside of Africa, but is routinely confiscated "by Quarantine Authorities at US airports, especially Baltimore, Dulles, JFKIA, and San Francisco." These very large snails are kept as pets in the Western world, where owners prize their large size, distinctive markings, and rarity.

This species has not yet become established in the USA, but it is considered to represent a potentially serious threat as a pest, an invasive species

Invasive species

"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....

 which could negatively affect agriculture, natural ecosystems, human health or commerce. There is a population of these snails spreading in Coral Gables, Florida

Coral Gables, Florida

Coral Gables is a city in Miami-Dade County, Florida, southwest of Downtown Miami, in the United States. The city is home to the University of Miami....

. Left unchecked the species has the potential to spread. It has been suggested that this species be given top national quarantine

Quarantine

Quarantine is compulsory isolation, typically to contain the spread of something considered dangerous, often but not always disease. The word comes from the Italian quarantena, meaning forty-day period....

 significance in the USA.

Description

The shells of these snails often grow to a length of 18 cm with a diameter of 9 cm, however certain examples have been surveyed in the wild at 30×15 cm, making them the largest extant land snail species known.

Ecology

Like almost all pulmonate gastropods, these snails are hermaphrodites, having male and female sex organs. Each snail lays up to twelve hundred eggs per year. The huge size of this snail and its potential for rapid population growth makes it a potentially serious pest problem where it is introduced.

The species' population size can be curtailed by disease caused by the bacterium Aeromonas liquefacians but it often has no other natural enemies.

However this snail is an important source of animal protein for West African forest-dwelling ethnic groups, and commercial farming of these snails holds great promise.