Giant African Land Snail

Quick Take

• This snail carries something far more dangerous than its size suggests, and that something is not its appetite. See the dangerous parasite →
• Florida declared victory against this snail once, only to start all over again. Florida's eradication history →
• It starts life as one sex, then becomes something else entirely as it matures. Explore its hermaphroditic nature →
• Its diet goes well beyond plants, and what it eats when food runs out is genuinely unsettling. Discover its unsettling diet →

As its name suggests, the Giant African Land Snail is one of the largest snails in the world. Although it is native to East Africa, it has been introduced to many other places. It is a destructive agricultural pest considered one of the top 100 invasive species in the world. The Giant African Land Snail evolved in tropical climes, but it has learned to thrive in more temperate areas and may even hibernate, or estivate, during the colder or drier months.

3 Incredible Facts

• One of the problems with an infestation of these snails is that they often carry parasites that cause infections or serious diseases such as meningitis or schistosomiasis.
• In the late 1960s, the state of Florida spent a million dollars and several years to eradicate this snail, but it was reintroduced in 2011 and 2021, so new eradication programs are working to prevent crop loss.
• The Giant African Land Snail never stops growing. Although its growth rate slows as it ages, it will keep growing until it dies.

Classification and Scientific Name

Although there are a few animals called the Giant African Land Snail, this article deals with the species Achatina fulica. The snail belongs to the Achatinidae family. It is also known by a number of synonyms and has five subspecies. The species name is derived from the Greek word for “agate,” and may describe the attractive pattern on the animal’s shell. Fulica is Latin for a type of waterfowl.

The ancestry of land snails, like the Giant African Land Snail, goes back around 350 million years, when they first crawled onto land where plant life had already taken hold. Adaptations followed to enable greater mobility and more efficient feeding.

Appearance

The first thing a person notices about a fully grown Giant African Land Snail is its size. The animal can reach up to 5 inches in diameter, can grow to nearly 8 inches long, and can easily fill the palm of a grown man’s hand. it weighs up to about 32 grams (roughly an ounce).

The largest of these snails was 14.7 inches long. That is still not as large as its cousin, Achatina achatina. The largest of these snails, named Gee Geronimo, had a body that was 15.5 inches long, and a shell that was 10.75 inches long and weighed 2 pounds.

In Achatina fulica, the shell is higher than it is wide, and the whorls turn either clockwise or counter-clockwise depending on the individual, although most snails have clockwise-turning shells. By the time the snail is grown, the shell can have between seven and nine whorls, or spirals. Most shells are shades of brown with attractive stripes and streaks. The color depends largely on the animal’s diet and environment. The shell of the Giant African Land Snail is famously tough and rich in heavy metals. Like all land snails, Achatina fulica’s muscular “foot” allows it to move. Its head has two pairs of fleshy tentacles.

Behavior

The Giant African Land Snail is largely solitary and seeks out other snails only when it is time to breed. Like most other land snails, it lays down a protective trail of slime as it moves over rough terrain. The shell is also used for protection. The brownish shades of A. fulica‘s shell help camouflage it as well.

The snail is active at night and sleeps during the day after it buries itself in soil. During the night, the snail leaves its shelter and seeks food. It does not hear as humans do, but it has other senses to alert it to its environment. Its eyes are found on the upper pair of its tentacles, and the lower pair possess olfactory organs. The snail relies mainly on these two senses to help it navigate the world.

A group of these snails is collectively called a walk, a trail, an escargatoire, or a rout.

Habitat

This giant snail originated in what are now the countries of Mozambique, Tanzania, Kenya, Somalia, and Ethiopia and is currently found in much of the world, including Asia, the Caribbean, and North and South America. Habitats where A. fulica flourishes include the coast, the forests, around rivers, shrublands and wetlands, and even cities. Since the snail doesn’t migrate, this means it was introduced into these other areas, either accidentally or deliberately. Some were collected as pets and escaped; others arrived on cargo ships or hitched rides on vehicles; still others were introduced as a food source. Because one gravid snail can lay hundreds of eggs at a time, snail populations can easily explode in countries where the species is not native.

Diet

The snail is an herbivore and will eat an amazing variety of plant-based materials. Biologists have counted at least 500 types of plants that the snail will eat. It does not care if the plant is living or dead. This snail will even eat paper and concrete. To fortify its shell, it will eat sources of calcium such as pebbles, sand, and bones. It will also eat the dead bodies of small animals. When food is really scarce, Giant African Land Snails will eat their own eggs or resort to cannibalism.

The diet of the snail changes as it ages. Young snails are partial to algae and plants and flowers that are soft or even rotting, although a snail caretaker should not feed a snail decaying food, as it may still cause illness. Older snails prefer fresh, living vegetation, including fruits and vegetables such as cucumbers, bananas, and lettuce. The snail is able to consume such a varied diet because it possesses a radula — a ribbon-like organ resembling a tongue covered in serrated teeth. This organ rasps and grates the animal’s food, making it easier to digest.

Predators and Threats

The Giant African Land Snail has a great many predators. These include rats, foxes, wild boars, hermit crabs, and other snails such as the cannibal snail. Fire ants and flatworms also attack and devour A. fulica, especially when it’s young. Despite this, the snail is not endangered.

Reproduction, Babies, and Lifespan

One of the most fascinating things about the Giant African Land Snail is that it is a hermaphrodite, which means it has both male and female reproductive organs. The snail starts life as a male, then becomes a hermaphrodite as it matures.

Since the snail can’t fertilize itself, it must seek a mate. A. fulica is particular when it comes to a mate, and it chooses according to age and size. If the potential mate is the same size, chances are higher that both snails will become gravid. If one is larger, the larger snail acts as the female.

The snails begin by tenderly courting, then exchanging sperm, which can be stored in the snail’s body for as long as two years. Mating has been known to last as long as two hours, and it happens at night. The snail lays its eggs between 8 and 20 days later in nests, in the soil, or among rocks.

A snail that is laying eggs for the first time will probably lay only 100 or so. Later, it can lay as many as 500 eggs at a time. The older it gets, the more eggs it lays, and in hospitable climates, it can lay eggs every eight to twelve weeks.

About 90 percent of the eggs will hatch in approximately two weeks if the temperature goes above 59 degrees Fahrenheit. The baby snails, or hatchlings, are miniatures of their parents and do not undergo metamorphosis like sea snails. Neither parent provides care.

A. fulica is sexually mature when it is approximately 6 to 12 months old. It has a lifespan of about 3 to 5 years, although some have lived as long as 10 years. Whether the animal is kept in captivity or lives in the wild does not seem to significantly affect its lifespan. Although predators keep the numbers of these snails in check in their native areas, introduced snails die of old age, succumb to eradication programs, or perish because the climate is inhospitable even for them.

Population

Given how quickly A. fulica reaches reproductive age, its fecundity, and its ability to quickly adapt to different habitats, there are probably millions of them worldwide. In Africa alone, they are found in 14 countries and are considered invasive in 8 of them, including Ghana, Madagascar, Nigeria, and the Seychelles.

The snail is found in 21 Asian countries, including Nepal, Israel, Sri Lanka, Japan, and Vietnam, and is considered invasive in all five of them. The snail is also found in Italy and Spain but is under eradication in Italy.

In the United States, the snail is found in Florida, Hawaii, and Wisconsin and is invasive in Florida and Hawaii. A. fulica was first found in Florida in 1969, was eradicated, but returned in 2011 and is now under eradication again.

A. fulica is also invasive in many areas of Oceania, including American Samoa, French Polynesia, Palau, Papua New Guinea, and Samoa. It was eradicated in Tuvalu.

The snail is also invasive in much of South America, including Argentina, Brazil, Colombia, Ecuador, Paraguay, Peru, and Venezuela.

The snail has been introduced as early as before 1800 in Madagascar and as recently as 2013 in the Netherlands Antilles.

In the Zoo

Despite its ubiquity, the snail is still exhibited in zoos, including:

• Belfast Zoo
• London Zoo
• Noah’s Ark Zoo Farm