Land snails, visible to the naked eye due to their distinctive shells and soft, sticky bodies, belong to the phylum Mollusca and class Gastropoda. Gastropoda is the most diverse and largest group of mollusks. Their well-developed lungs allow them to inhabit dry land and occupy diverse environments, primarily feeding on plant species. Want to learn more about land snails? Then don't miss the following article, where we'll tell you what snails are, their characteristics, and types.
What is a land snail?
Terrestrial snails are pulmonary invertebrates, belonging to the phylum Mollusca and class Gastropoda due to their characteristics. Within this class, most terrestrial snails belong to the order Cyclops, also known as Cyclops.
One of the most striking characteristics of terrestrial snails is that they have developed lungs and lost their gills. This allows them to breathe through the air, a fundamental adaptation for their transition to terrestrial environments.
Characteristics of land snails
They have lost their original gills, but their vascularized mantle walls have transformed into lungs. The air inlet and outlet openings are called spiracles.
They have a hard, single shell containing internal organs, which helps prevent dehydration and predation.
Some species, such as those belonging to the Clausiliidae family, have a calcareous structure called aclausilio, which allows them to close the opening of their shells and protect their soft parts.
Their feet are flat and muscular, with mucus glands that help them move and grasp on different surfaces.
They have two pairs of tentacles, with the eyes located in the latter pair.
Their mantle is a double-folded outer skin that covers and protects the internal organs containing different organ systems.
Types of land snails
Common garden snail (Cornu aspersum): Native to continental Europe, but has been introduced to various regions of other countries, causing invasive damage to crops. It is highly valued in Mediterranean cuisine.
Land snail (Rumina decolata): Native to the Mediterranean and North Africa, it is an omnivorous species, as it not only feeds on plants but also preys on garden snails, slugs, and their eggs.
Helicella stiparum: Characterized by its hard white shell, it lives in the dry soil and xerophytic vegetation of the Almería province of Spain.
Megalophaedusa martensi: Endemic to Japan, it is the largest extant species of the family Megalophaedusa in the world.
The giant tiger snail (Achatina achatina): native to West Africa, it can reach a length of 18 centimeters and is one of the largest known snails in the world.
Plagiodontes rocae: Endemic to the Sierra de la Ventana mountain range in southwestern Buenos Aires Province, Argentina.
Where do land snails live?
The habitat of terrestrial snails is determined by a variety of factors, such as the mineral composition of the soil, humidity, temperature, and acidity. Although they prefer damp and shady places, surprisingly, some species defy these limitations and live in high-altitude and seemingly desolate areas. Their most common habitats are associated with environments such as forests, roadsides, grasslands, and clearings. Similarly, they have successfully adapted to urban environments, making their homes in corners of vegetation formed from leaf debris, under tree trunks, under tree roots, or in underground depressions.
Some species are able to survive in arid environments, calcareous soils, and volcanic soils. These species often hide under rocks, in withered cacti, or even among grass roots. Furthermore, their adaptability extends to aquatic environments, such as the banks of streams and rivers, and on hillsides.
In conclusion, the diversity of terrestrial snail habitats is impressive, demonstrating their ability to find shelter under a variety of environmental conditions.
Feeding terrestrial snails
Although their diets vary—some species are omnivorous, consuming both plants and other mollusks—land snails are typically herbivorous, with radulas adapted to feed on different plant species at night. Some species, such as Cornu aspersum, have been introduced outside their native ranges and behave as invasive alien species, often associated with high-yield crops and causing significant economic losses.
Snails' shells, like their eggshells, are primarily composed of calcium carbonate, so they rely on the availability of calcium in their diet to form a strong, sturdy shell. Calcium deficiency or changes in habitat pH can have detrimental effects, such as causing thin shells, cracks, or even perforations.
Reproduction of land snails
Terrestrial snails are hermaphroditic, producing both eggs and sperm. Generally, mating occurs first, followed by a complex courtship process, during which sperm are transferred using the seminal vesicle. In snails of the Spiralidae family, the vagina secretes a calcareous needle-like structure. When two snails "embrace," this needle-like structure is used to pierce the other's body. This process may be related to a stimulation method where one individual acts as male and the other as female, since snails do not carry sex cells. After this complex courtship process, the seminal vesicle is transferred from one individual's male sex organ to another's female sex organ, where sperm is released, and subsequently, the egg is fertilized.
Terrestrial species are oviparous, producing a small number of eggs encased in albumen and possessing their own protective capsule, which serves as a calcium source for shell formation. Eggs are laid in small groups on the ground.
Now that you know what land snails are, their characteristics, and types, you may also be interested in articles about snail parts and how long snails can live.
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