Animal Diversity Web

Ge­o­graphic Range

Achatina fulica orig­i­nated in the coastal areas and is­lands of East Africa, where it pre­sum­ably got the nick­name, “Giant African Snail.” The snail in­hab­its coun­tries rang­ing from Mozam­bique in the south, to Kenya and So­ma­lia in the north. It is not only found in East Africa on the coastal areas and is­lands, but it has also been in­tro­duced to many other coun­tries in Africa, along with many coun­tries world­wide. The snail has been in­tro­duced into coun­tries as far apart as the United States to Aus­tralia, and coun­tries in-be­tween. Achatina fulica is not a mi­gra­tory species and has there­fore been in­tro­duced through other means to the coun­tries out­side of East Africa, pos­si­bly through agri­cul­tural trans­porta­tion, com­merce, trade, ve­hi­cle at­tach­ment, smug­gling, and other ac­ci­den­tal and pur­pose­ful ways. ("Achatina fulica", 2014a; "Giant African snail", 2013; "Lis­sachatina fulica", 2014; "Snails (Giant East African Snail)", 2012; Cowie, 2010; Egon­mwan, 2007; Stokes, 2006; Vogler, et al., 2013)

• Biogeographic Regions
• nearctic
  • introduced
• palearctic
  • introduced
• oriental
  • introduced
• ethiopian
  • native
• neotropical
  • introduced
• australian
  • introduced

Habi­tat

The giant African land snail has a nat­ural habi­tat lo­cated in Africa, where there is a trop­i­cal cli­mate with warm, year round tem­per­a­tures, and high hu­mid­ity. The snail has adapted and has been able to thrive in tem­per­ate cli­mates as well. This species prefers areas of low to mid-el­e­va­tion, with tem­per­a­ture pref­er­ence be­tween nine de­grees Cel­sius and twenty-nine de­grees Cel­sius. Achatina fulica can sur­vive less ideal con­di­tions, such as two de­grees Cel­sius by hi­ber­na­tion and thirty de­grees Cel­sius by aes­ti­va­tion. The snail can be found in agri­cul­tural areas, coastal areas, wet­lands, dis­turbed areas, forests, urban areas, and ri­par­ian zones. The snails need tem­per­a­tures above freez­ing and prefer­ably high hu­mid­ity in order to thrive the best. They have adapted to dry and cooler areas, how­ever, by being able to hi­ber­nate in soft soil dur­ing the un­fa­vor­able weather con­di­tions. ("Achatina fulica", 2014a; "Snails (Giant East African Snail)", 2012; Cowie, 2010; Stokes, 2006; Vogler, et al., 2013)

• Habitat Regions
• temperate
• tropical
• terrestrial

• Terrestrial Biomes
• savanna or grassland
• forest

• Other Habitat Features
• urban
• agricultural
• riparian

Phys­i­cal De­scrip­tion

The giant African snail can be dis­tin­guished from other snails due to their large size; when ma­ture, the snail can reach up to eight inches (30 cen­time­ters) in length with a di­am­e­ter of four inches (10 cen­time­ters). The snail can reach up to thirty-two grams in weight. The snail has the phys­i­cal fea­tures that are as­so­ci­ated with the phy­lum Mol­lusca, in­clud­ing a shell. The shell of Achatina fulica is cone-shaped and has a height that is twice that of the width. When the snail is ma­ture and full-grown, the shell will nor­mally con­sist of seven to nine whorls. The color of the snail dif­fers de­pend­ing on the en­vi­ron­ment, as some are pri­mar­ily brown or dark col­ored, with dark stripes and streaks that run across the whorls, while oth­ers are red­dish-brown with pale yel­low ver­ti­cal mark­ings. ("Achatina fulica", 2014a; "Achatina fulica", 2014b; "Giant African Land Snail", 2008; "Giant African snail", 2013; "Pest Alert", 2011; "Snails (Giant East African Snail)", 2012; Cowie, 2010; Stokes, 2006)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Average mass

  32 g

  1.13 oz

• Range length

  30 (high) cm

  11.81 (high) in

De­vel­op­ment

The fer­til­ized eggs of A. fulica are laid in a nest, or in the dirt and leaves, so as to pro­tect and dis­guise the eggs. The eggs then hatch and be­come im­ma­ture snails, which grow to adult­hood in about six months. Achatina fulica is one of many land snails, which do not have a lar­vae phase like other Gas­tro­pod species. ("Achatina fulica", 2014a; "Achatina fulica", 2014b)

Re­pro­duc­tion

Achatina fulica is her­maph­ro­ditic; each in­di­vid­ual snail has both male and fe­male re­pro­duc­tive parts. There are no dis­tin­guish­ing parts sep­a­rat­ing sexes be­cause each snail con­tains both sex re­pro­duc­tive sys­tems. They do not self-fer­til­ize, so the snails need to mate with an­other snail of their species. As a Sty­lom­matophiora, Achatina fulica does not mate ran­domly; the snails mate with re­spect to age and size of other snails. Im­ma­ture, small snails that are still grow­ing pro­duce only sper­ma­to­zoa, while larger, ma­ture adults pro­duce both sper­ma­to­zoa and ova. There is an age de­pen­dent mate choice when it comes to young snails be­cause they need and pre­fer older adults to mate with. Young giant African snails cop­u­late at all hours of the night, while older adults mate in the mid­dle of the night. The snails choose their mates with re­spect to size and age, but the re­pro­duc­tive stage-de­pen­dent mate is a more at­trac­tive mate than the body size-de­pen­dent mate choice. Mat­ing oc­curs when one snail en­coun­ters a prospec­tive part­ner that the in­di­vid­ual snail deems ac­cept­able to mate with. When two in­di­vid­ual snails mate, there is a pos­si­bil­ity that ga­metes will be trans­ferred to each one by the other si­mul­ta­ne­ously. How­ever, this is only the case if the snails are around the same size. If there is a size dif­fer­ence, the larger snail will act as the fe­male and the ga­metes will only be trans­ferred from the smaller snail to the larger snail, mat­ing uni­lat­er­ally. ("Achatina fulica", 2014a; "Giant African Land Snail", 2008; "Giant African snail", 2013; "Lis­sachatina fulica", 2014; "Pest Alert", 2011; Cowie, 2010; Egon­mwan, 2007; Tomiyama, 1996)

When two A. fulica en­counter and deem each other wor­thy mates, they will mate by one mount­ing the shell of the other. The mat­ing will begin once the two snails ex­change sperm with one an­other. The sperm is used to fer­til­ize the eggs in the snails, but it can also be stored in­side the body for up to two years. The fer­til­ized eggs are laid be­tween eight and twenty days after mat­ing has oc­curred, and are de­posited in nests or among rocks and soils on the ground. The eggs usu­ally hatch at tem­per­a­tures above fif­teen de­grees Cel­sius. The eggs, under the right con­di­tions, will hatch after eleven to fif­teen days into small snails. The num­ber of eggs that an in­di­vid­ual snail lays often de­pends on the ma­tu­rity and age of the snail and is be­tween 100 to 500 eggs. Giant African snails have no spe­cific sea­son of mat­ing, as they are able to pro­duce new clutches every two to three months. ("Achatina fulica", 2014a; "Giant African snail", 2013; Egon­mwan, 2007; Tomiyama, 1996)

• Key Reproductive Features
• iteroparous
• year-round breeding
• sequential hermaphrodite
  • protandrous
• sexual
• induced ovulation
• fertilization
  • internal
• oviparous
• sperm-storing

• Breeding interval

  The giant African snail breeds every two to three months.

• Breeding season

  Breeding can take place any time of the year.

• Range number of offspring

  100 to 500

• Average number of offspring

  200

• Range gestation period

  11 to 15 days

• Average age at sexual or reproductive maturity (female)

  6 months

• Average age at sexual or reproductive maturity (male)

  6 months

The par­ents of Achatina fulica do not con­tribute to the lives of their off­spring ex­cept for fer­til­iza­tion and lay­ing of the eggs in nests or soil. Once the eggs are hatched, the small in­di­vid­u­als are on their own and adopt the ter­ri­tory that their par­ent pro­vided them. (Cowie, 2010; Egon­mwan, 2007)

• Parental Investment
• pre-hatching/birth
  • provisioning

Lifes­pan/Longevity

Achatina fulica can live on av­er­age be­tween three and five years, with some in­di­vid­u­als reach­ing as old as ten years. There is not much dif­fer­ence be­tween the lifes­pans in the wild and in cap­tiv­ity. In their nat­ural habi­tat, preda­tors are a main cause of mor­tal­ity of Achatina fulica, how­ever as they have be­come an in­va­sive species, their new habi­tats con­tain close to zero preda­tors. The snails usu­ally die due to nat­ural causes or non-fa­vor­able liv­ing con­di­tions. Re­cently, there have been de­vel­op­ments in mol­lus­ci­cides that have been im­pact­ful on killing this species, in order to bet­ter con­trol their pop­u­la­tion in un­wanted areas. ("Achatina fulica", 2014a; "Lis­sachatina fulica", 2014; Cowie, 2010)

• Range lifespan
  Status: wild

  10 (high) years

• Typical lifespan
  Status: wild

  3 to 5 years

• Typical lifespan
  Status: captivity

  3 to 5 years

Be­hav­ior

Achatina fulica is a soli­tary species. The par­ents do not have an im­pact in their off­springs’ lives once the eggs are hatched, so the soli­tary be­hav­ior is in­tact from the be­gin­ning. It is not pos­si­ble for A. fulica to self-fer­til­ize, so courtship and in­ter­ac­tion is a nec­es­sary as­pect of their lives. Move­ment is an im­por­tant as­pect of their lives as it is nec­es­sary for mat­ing, find­ing food, and es­cap­ing threats. Achatina fulica se­cretes a slime-like sub­stance that al­lows for smooth and easy travel dur­ing its move­ment. The sub­stance pro­tects and al­lows travel across rough and sharp sur­faces. Achatina fulica is a noc­tur­nal species and lies dor­mant dur­ing the day. The snails often bury them­selves in soil, in order to stay cool and re­main hid­den from threats. Giant African snails can also sur­vive cold con­di­tions by aes­ti­vat­ing; they be­come slow and slug­gish as they wait for warmer and more de­sired con­di­tions to occur. ("Lis­sachatina fulica", 2014; "Pest Alert", 2011)

• Key Behaviors
• terricolous
• nocturnal
• motile
• sedentary
• aestivation
• solitary

Com­mu­ni­ca­tion and Per­cep­tion

Achatina fulica does not need to com­mu­ni­cate often, as it is not a so­cial species. The time of com­mu­ni­ca­tion among the species takes place in the process of mat­ing, as one will mount the back of an­other in­di­vid­ual. Com­mu­ni­ca­tion takes place as there is a change in the po­si­tion of the head, along with changes in the move­ment of the body. The changes in the body and head are com­mu­ni­ca­tion cues that in­di­cate that the mat­ing process will con­tinue. Achatina fulica does not have hear­ing as a sense, so it re­lies on its other senses to per­ceive the en­vi­ron­ment. This species also has cau­dal ten­ta­cles; the upper pair of ten­ta­cles have eyes at the tips and the lower pair have the sen­sory organ that al­lows for smell. This species has a strong sense of smell, which as­sists in find­ing food sources. The com­bi­na­tion of smell and sight is how this species per­ceives the en­vi­ron­ment around them and al­lows for the de­tec­tion of food, mates, and po­ten­tial threats. ("Achatina fulica", 2014a; "Giant African snail", 2013; Cowie, 2010; Egon­mwan, 2007)

• Communication Channels
• visual
• tactile

• Perception Channels
• visual
• chemical

Food Habits

Giant African snails are her­bi­vores. Achatina fulica feeds pri­mar­ily on vas­cu­lar plant mat­ter, hav­ing no pref­er­ence whether it is liv­ing or dead mat­ter. This snail species has a strong sense of smell that as­sists in at­tract­ing and lead­ing the in­di­vid­u­als to gar­den crops and other plant re­sources. These snails have dif­fer­ent pref­er­ences with their ages; young mem­bers of this species feed on de­cay­ing mat­ter and uni­cel­lu­lar algae. They also pre­fer soft tex­tured Musa (ba­nanas), Beta vul­garis (beets), and Tagetes pat­ula (marigolds). More ma­ture and de­vel­oped African snails pre­fer to feed on liv­ing plants and veg­e­ta­tion. The ma­ture snails broaden their spec­trum of pre­ferred plants to con­sume in­clud­ing: Solanum me­l­on­gena (egg­plant), Cu­cumis sativus (cu­cum­ber), Cu­cur­bita pepo (pump­kin), and many oth­ers. This species has also been found to feed on other snails, lichens, fungi, and an­i­mal mat­ter. The radula, a dis­tin­guish­ing char­ac­ter­is­tic of Gas­tropods, is es­sen­tial in the abil­ity to eat a va­ri­ety of foods. The radula is a toothed rib­bon used to scrape or cut food, and al­lows for the abil­ity to pick up food and begin the di­ges­tive process with ease. ("Achatina fulica", 2014a; "Giant African Land Snail", 2008; "Lis­sachatina fulica", 2014; "Snails (Giant East African Snail)", 2012; Cowie, 2010)

• Primary Diet
• herbivore
  • folivore
  • frugivore

• Animal Foods
• mollusks

• Plant Foods
• leaves
• wood, bark, or stems
• seeds, grains, and nuts
• fruit
• flowers
• lichens
• algae

• Other Foods
• fungus
• detritus

Pre­da­tion

Achatina fulica has a shell from the be­gin­ning of its life until the end. The shell is used for pro­tec­tion against the en­vi­ron­men­tal con­di­tions and po­ten­tial preda­tors. The shell also pro­vides pro­tec­tion for the in­ter­nal or­gans against out­side forces. The col­ors of A. fulica tend to be more earthy tones, as to not stand out in its en­vi­ron­ments and to be more cam­ou­flaged from the sight of their preda­tors. Preda­tors of Achatina fulica in­cludes many species of ro­dents, wild boars, ter­res­trial crus­taceans, and other species of snails. ("Giant African Land Snail", 2008; "Lis­sachatina fulica", 2014; "Snails (Giant East African Snail)", 2012)

• Known Predators

  • Christmas Island red crab, Gecarcoidea natalis
  • cannibal snail, Euglandina rosea
  • land snail, Gonaxis quadrilateralis
  • fire ants, Solenopsis geminata
  • hermit crabs, Paguroidea
  • Malayan field rat, Rattus tiomanicus
  • Polynesian rat, Rattus exulans
  • Rice-field rat, Rattus argentiventer
  • wild boar, Sus scrofa
  • New Guinea flatworm, Platydemus manokwari

Ecosys­tem Roles

Achatina fulica has sev­eral dif­fer­ent ecosys­tem roles. This species de­com­poses and con­sumes dead veg­e­ta­tion. The ben­e­fit of this ecosys­tem role is that the snail as­sists in re­cy­cling nu­tri­ents and the build­ing blocks es­sen­tial to life. Giant African snails are also part of the food chain, as they are a source of food to many preda­tors. This species is also a host to par­a­sitic or­gan­isms, such as An­giostrongy­lus can­to­nen­sis, the rat lung­worm. The par­a­sitic or­gan­isms live and thrive on this host and can be trans­ported to other hosts, such as hu­mans, through the con­sump­tion of the snails. ("Achatina fulica", 2014a; "Achatina fulica", 2014b; Car­valho, et al., 2003; Cowie, 2010; Stokes, 2006)

• Ecosystem Impact
• biodegradation

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Snails are often seen as a del­i­cacy for hu­mans and A. fulica is no ex­cep­tion. Hu­mans around the world con­sume giant African snails as a source of pro­tein when pre­pared cor­rectly. This species is also a cheap al­ter­na­tive in some re­gions as a source of fish feed in fish farm­ing, as they breed quickly and in large amounts. Achatina fulica can also be ben­e­fi­cial in mak­ing fer­til­izer, chicken feed, and bi­o­log­i­cal com­pounds in clin­i­cal and ex­per­i­men­tal lab­o­ra­to­ries. ("Achatina fulica", 2014a; "Lis­sachatina fulica", 2014; Stokes, 2006)

• Positive Impacts
• pet trade
• food

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Giant African snails are an in­va­sive species across that world. It has be­come il­le­gal to have pos­ses­sion of these snails in coun­tries where it has been in­tro­duced. Achatina fulica has a large and broad diet pref­er­ence; the di­etary habits of this species cause a high loss in crops for farm­ers. They are con­sid­ered an agri­cul­tural pest, cost­ing farm­ers not only their crops but also eco­nomic costs. This species is also a car­rier of many par­a­sitic or­gan­isms, in­clud­ing or­gan­isms that harm peo­ple and plants. Se­ri­ous ill­ness and dis­eases can erupt in hu­mans if they con­sume giant African snails. Achatina fulica also de­stroys and pol­lutes its sur­round­ings, in­clud­ing soil. When an in­di­vid­ual of this species dies, the cal­cium car­bon­ate found in the shells neu­tral­izes the soil; the neu­tral­iza­tion of the soil and the al­ter­ing of its prop­er­ties af­fect the types of plants that can grow in the soil. Achatina fulica can cost cities, states, or coun­tries mil­lions of dol­lars in not only agri­cul­tural costs, but also in at­tempts to con­trol this in­va­sive species. ("Achatina fulica", 2014a; "Achatina fulica", 2014b; "Giant African Land Snail", 2008; "Lis­sachatina fulica", 2014; "Species Pro­files: Giant African Snail", 2014; Car­valho, et al., 2003; Cowie, 2010; Stokes, 2006)

• Negative Impacts
• injures humans
  • causes disease in humans
• crop pest

Con­ser­va­tion Sta­tus

Achatina fulica is not cur­rently vul­ner­a­ble, threat­ened, nor en­dan­gered.

• IUCN Red List

  Not Evaluated

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Con­trib­u­tors

Tay­lor Hoff­man (au­thor), Grand View Uni­ver­sity, Nicole Pirie (au­thor), Grand View Uni­ver­sity, Fe­lic­i­tas Aven­dano (ed­i­tor), Grand View Uni­ver­sity, Dan Chib­nall (ed­i­tor), Grand View Uni­ver­sity, An­gela Miner (ed­i­tor), An­i­mal Di­ver­sity Web Staff.

Ref­er­ences

2014. "Achatina fulica" (On-line). En­cy­clo­pe­dia of Life. Ac­cessed March 09, 2014 at http://​eol.​org/​pages/​452699/​details.

2014. "Achatina fulica" (On-line). In­sti­tute for the Study of In­va­sive Species. Ac­cessed March 07, 2014 at http://​www.​tsusinvasives.​org/​database/​giant-african-snail.​html.

2008. "Giant African Land Snail" (On-line). Mass­a­chu­setts In­tro­duced Pests Out­reach Pro­ject. Ac­cessed Feb­ru­ary 28, 2014 at http://​massnrc.​org/​pests/​pestFAQsheets/​giantafricanlandsnail.​html.

2013. "Giant African snail" (On-line). ARKive. Ac­cessed Feb­ru­ary 28, 2014 at http://​www.​arkive.​org/​giant-african-snail/​achatina-fulica/​.

2014. "Lis­sachatina fulica" (On-line). In­va­sive Species Com­pendium. Ac­cessed March 07, 2014 at http://​www.​cabi.​org/​isc/?​compid=5&​dsid=2640&​loadmodule=datasheet&​page=481&​site=144.

2011. "Pest Alert" (On-line pdf). United States De­part­ment of Agri­cul­ture. Ac­cessed March 07, 2014 at http://​www.​aphis.​usda.​gov/​publications/​plant_​health/​content/​printable_​version/​pa_​phgas.​pdf.

2012. "Snails (Giant East African Snail)" (On-line). In­fonet-Bio­vi­sion. Ac­cessed March 08, 2014 at http://​www.​infonet-biovision.​org/​default/​ct/​110/​pests.

2014. "Species Pro­files: Giant African Snail" (On-line). United States De­part­ment of Agri­cul­ture. Ac­cessed Feb­ru­ary 26, 2014 at http://​www.​invasivespeciesinfo.​gov/​animals/​africansnail.​shtml.

Car­valho, O., H. Teles, E. Mota, C. Lafeta, G. Men­donca, H. Lenzi. 2003. Po­ten­tial­ity of Achatina fulica Bowdich, 1822 (Mol­lusca: Gas­tropoda) as in­ter­me­di­ate host of the An­giostrongy­lus costari­cen­sis Mor­era & Céspedes 1971. Re­vista da So­ciedade Brasileira de Med­i­c­ina Trop­i­cal, 36/6: 743-745. Ac­cessed March 06, 2014 at http://​www.​scielo.​br/​pdf/​rsbmt/​v36n6/​a17v36n6.​pdf.

Cowie, R. 2010. "Achatina fulica (mol­lusc)" (On-line). Global In­va­sive Species Data­base. Ac­cessed March 06, 2014 at http://​www.​issg.​org/​database/​species/​ecology.​asp?​si=64&​fr=1&​sts=sss&​lang=N.​.

Egon­mwan, R. 2007. "Re­cent Ad­vances in the Bi­ol­ogy of Giant African Land Snails" (On-line pdf). Fed­eral Uni­ver­sity of Agri­cul­ture, Abeokuta. Ac­cessed March 05, 2014 at http://​unaab.​edu.​ng/​netgals/​downloads/​Egonmwan.​pdf.

Stokes, H. 2006. "In­tro­duced Species Sum­mary Pro­ject" (On-line). Co­lum­bia Uni­ver­sity. Ac­cessed March 04, 2014 at http://​www.​columbia.​edu/​itc/​cerc/​danoff-burg/​invasion_​bio/​inv_​spp_​summ/​Achatina_​fulica.​htm#​Introduction_​Facts.

Tomiyama, K. 1996. MATE-CHOICE CRI­TE­RIA IN A PROTAN­DROUS SI­MUL­TA­NE­OUSLY HER­MAPH­RO­DITIC LAND SNAIL ACHATINA FULICA (FÉRUS­SAC) (STY­LOM­MATOPHORA: ACHA­TINIDAE). Jour­nal of Mol­lus­can Stud­ies, 62: 101-111. Ac­cessed March 07, 2014 at http://​mollus.​oxfordjournals.​org/​content/​62/​1/​101.​full.​pdf+html.

Vogler, R., A. Bel­tramino, M. Sede, D. Gre­goric, V. Nunez, A. Rumi. 2013. The giant African snail, Achatina fulica (Gas­tropoda: Acha­tinidae): Using bio­cli­mat­ic­mod­els to iden­tify South Amer­i­can areas sus­cep­ti­ble to in­va­sion. Amer­i­can Mala­co­log­i­cal Bul­letin, 31/1: 39-50. Ac­cessed March 04, 2014 at http://​www.​academia.​edu/​2602901/​The_​Giant_​African_​Snail_​Achatina_​fulica_​Gastropoda_​Achatinidae_​Using_​Bioclimatic_​Models_​to_​Identify_​South_​American_​Areas_​Susceptible_​to_​Invasion.