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giant african snail

Achatina fulica

What do they look like?

Giant African snails can grow up to 8 inches/30 cm in length, which is why they are called "giant" snails. The snails can also reach up to 32 grams in weight. They have a cone shaped shell, and the shell is twice as high as it is wide. When the snail is full grown, its shell will have 7 to 9 spirals. The color of the shell differs depending on the environment. Some shells are brown or dark colored, with dark stripes, 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)

  • Average mass
    32 g
    1.13 oz
  • Range length
    30 (high) cm
    11.81 (high) in

Where do they live?

Achatina fulica, the giant African land snail, is originally from the coastal areas and islands of East Africa. The snail lives in countries ranging from Mozambique in the south, to Kenya and Somalia in the north. Giant African land snails used to live only in this area in Africa, but their range has grown as they have been brought to many other countries and continents throughout the world, from the United States to Australia and many in-between. These snails do not travel to other countries and continents on their own; they get transported by people, on purpose and accidentally. Some people smuggle these snails into other countries, while in other cases, snails may get caught up in cargo or on vehicles that bring them to a new location. ("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)

What kind of habitat do they need?

In its original habitat in Africa, the giant African land snail lives in a tropical climate with warm temperatures year round and high humidity. Since it has been brought to so many other areas in the world, it has learned to live in cooler climates. This species prefers areas of low to mid-elevation, with temperatures between nine degrees Celsius and twenty-nine degrees Celsius. It can also survive in temperatures even colder by hibernating in the ground and warmer temperatures by becoming inactive. These snails live in agricultural areas, coastal areas, wetlands, forests, urban areas, and riparian zones. ("Achatina fulica", 2014a; "Snails (Giant East African Snail)", 2012; Cowie, 2010; Stokes, 2006; Vogler, et al., 2013)

How do they grow?

The fertilized eggs are laid in a nest, or in the dirt and leaves, to protect and disguise the eggs. The eggs then hatch and become immature snails, which grow to adulthood in about six months. ("Achatina fulica", 2014a; "Achatina fulica", 2014b)

How do they reproduce?

Giant African snails are hermaphrodites. This means that instead of having male and female snails, each snail has both male and female reproductive parts. Young snails only produce sperm, but as they grow larger, they will produce both sperm and eggs. Even though they have both male and female parts, the snails still need to mate with another snail. Their own sperm cannot fertilize their own eggs. Since only older snails have both sperm and eggs, young snails (who only have sperm) usually mate with older snails (though older snails can also mate with older snails). Young giant African snails mate at all hours of the night, while older adults mate in the middle of the night. The snails choose their mates based on size and age. If two older snails decide to mate, both may pass sperm to the other snail. If it is a old snail and a young snail, the young snail will pass sperm to the old snail. Size also has an effect. If it is a larger snail and a smaller snail, the larger snail will act as a female and the smaller snail will pass his sperm to the larger snail. ("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 giant African snails mate, the two snails exchange sperm. The sperm may immediately fertilize the eggs, or the sperm can be stored inside the body for up to 2 years before fertilizing any eggs. When the eggs are fertilized, the snail does not lay them until 8 to 20 days later. They are laid in nests or among rocks and dirt on the ground. The eggs usually hatch after 11 to 15 days. The number of eggs that a snail lays often depends on the age of the snail and is between 100 to 500 eggs. Giant African snails are able to produce new batches of eggs every two to three months. ("Achatina fulica", 2014a; "Giant African snail", 2013; Egonmwan, 2007; Tomiyama, 1996)

  • How often does reproduction occur?
    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 only care that giant African snails give to their offspring is to lay the eggs in nests or soil, which usually protects the eggs from predators and other threats. After the eggs are laid, the parents leave. The young snails are on their own once they hatch. (Cowie, 2010; Egonmwan, 2007)

  • Parental Investment
  • pre-hatching/birth
    • provisioning

How long do they live?

Giant African snails live for 3 to 5 years, though some snails have been known to live as long as 10 years. In their natural habitat, predators are the main reason for the death of these snails. In the other areas across the world that they have been brought to, these snails do not have many predators. In these areas, the snails usually die from natural causes. ("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

How do they behave?

Giant African land snails spend most of their time by themselves, except when mating. These snails produce a slime that they use when they move. By putting the slime on the surface of the ground, and then moving on the slime, the slime reduces friction and allows them to move smoothly over any rough surfaces. Giant African snails are nocturnal, meaning that they are active during the night and inactive during the day. They often bury themselves in soil, which helps them to stay cool and also to hide from any predators. If temperatures get really warm or really cold, these snails can survive by becoming inactive and basically hibernating. They will become slow and sluggish until temperatures and weather conditions go back to normal. ("Lissachatina fulica", 2014; "Pest Alert", 2011)

How do they communicate with each other?

One of the few times that giant African snails have to communicate with each other is during mating. This is done with sight and with touch, as one snail will climb on top of the other snail. They also will change the position of their heads, and change the movement of their bodies. These snails cannot hear. They have two pairs of tentacles. The upper pair of tentacles have eyes at the tip, while the lower pair of tentacles have an organ that senses smells. They use smell to find food. ("Achatina fulica", 2014a; "Giant African snail", 2013; Cowie, 2010; Egonmwan, 2007)

What do they eat?

Giant African snails are herbivores and eat plant matter. Young snails tend to feed more on decaying matter and algae. They also eat soft fruits such as bananas and beets. Older snails feed on living plants. These snails may also eat other snails, lichens, fungi, and animal matter. They have a body part called the radula, which can be compared to a tongue. It has many teeth on it and is used to scrape or cut food. ("Achatina fulica", 2014a; "Giant African Land Snail", 2008; "Lissachatina fulica", 2014; "Snails (Giant East African Snail)", 2012; Cowie, 2010)

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

What eats them and how do they avoid being eaten?

Predators of giant African snails include many species of rodents, wild boars, terrestrial crustaceans, and other species of snails. These snails have large shells that is used to protect the soft inner body parts against predators. Giant African snails are also usually brown in color, which helps to camouflage them in their environment. ("Giant African Land Snail", 2008; "Lissachatina fulica", 2014; "Snails (Giant East African Snail)", 2012)

What roles do they have in the ecosystem?

Giant African snails help the ecosystem by decomposing and consuming dead plants. This helps to recycle nutrients from the dead plants back into the environment. Giant African land snails are also a part of the food chain, since many predators eat them. They can also be attacked by parasites, such as Angiostrongylus cantonensis, the rat lungworm. The parasites live in the snail and can be transported to other animals, such as humans, when they eat infected snails. ("Achatina fulica", 2014a; "Achatina fulica", 2014b; Carvalho, et al., 2003; Cowie, 2010; Stokes, 2006)

Commensal or parasitic species (or larger taxonomic groups) that use this species as a host

Do they cause problems?

Giant African snails are an invasive species across that world. This means that these snails have been brought by people to other places in the world that they did not originally live, and they are causing problems for other animals and plants in these new areas. Since these snails will eat a large variety of plants, they will also eat agricultural crops. This causes a huge loss in crops for farmers, and they will lose money when they have less crops to sell. Giant African snails also can have parasites that can harm other animals if the animals eat the snails. This includes humans that eat the snails. Giant African snails can cost cities, states, or countries millions of dollars in not only crops losses, but also in attempts to prevent this species from doing any more damage. ("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)

How do they interact with us?

People around the world eat giant African snails. In some places, they are even considered a delicacy. Fish farmers may also use giant African snails as a cheap source of bait to feed fish. These snails can also be used when making fertilizer, chicken feed, and biological compounds in laboratories. ("Achatina fulica", 2014a; "Lissachatina fulica", 2014; Stokes, 2006)

Are they endangered?

Giant African snails are not an endangered species.

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.

 
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Hoffman, T. and N. Pirie 2014. "Achatina fulica" (On-line), Animal Diversity Web. Accessed November 19, 2017 at http://www.biokids.umich.edu/accounts/Achatina_fulica/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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