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Snail

life science Maturity 7-9 Next article →

A snail is a type of shelled gastropod, which is a large group of mollusks. While most people think only of land snails, the name actually includes many species of sea snails and freshwater snails. These animals are defined by having a coiled shell that is large enough for the body to retract into completely. If a gastropod lacks a shell or only has a tiny one, it is often called a slug.

Snail on the floor
Snail on the floor

Snails are incredibly diverse and live in many places. You can find them in dry deserts or in the abyssal depths of the sea. They are also found in ditches and freshwater environments.

The anatomy of a snail is quite complex and unique. Most snails share three main features: the foot, the mantle, and the radula. The foot is a muscular organ used for locomotion, or moving from place to place. Snails move by contracting their foot muscles to create wave-like patterns in a layer of mucus. This mucus helps them glide and reduces friction.

The mantle is the organ responsible for producing the shell. It secretes material along the shell opening, allowing the shell to grow throughout the snail's life. The mantle also creates a mantle cavity, which many snails use for gas exchange. Some snails use this cavity as a lung, while others use gills.

The snail shell is a fascinating structure made of specific materials. It is mainly composed of a mixture of proteins called conchin and calcium carbonate. Conchin makes up the outer layer, which is known as the periostracum. The inner layers consist of a network of calcium carbonate, conchin, and various mineral salts. The mantle builds the shell by adding material around a central axis called the columella. This process creates the spiraling patterns known as whorls. As a snail ages, the size of these whorls generally increases.

Feeding is another highly specialized process for snails. Most snails use a structure called a radula to eat. The radula is a ribbon-like, chitinous tongue covered in thousands of microscopic, tooth-like structures. It works much like a file, ripping food into very small pieces. These teeth are continuously made in a radular sac and then moved forward to the working zone. As the teeth move forward, they harden and mineralize.

Depending on the species, snails can be herbivores, scavengers, or even predatory carnivores.

Snails come in a massive range of sizes. The smallest land snail, Angustopila psammion, was discovered in 2022 and is only 0.6 mm in diameter. On the other end of the scale, the largest living sea snail is Syrinx aruanus, which can reach 900 mm in length. A famous large land snail was named Gee Geronimo. This specimen was collected in Sierra Leone in 1976. It weighed exactly 900 g and was measured in December 1978.

Mochesnail
Mochesnail

These extremes show how much snails have adapted to different niches.

Biological studies have helped us understand how snails are related. Scientists used to group snails with lungs into a group called Pulmonata. However, a molecular study in 2010 by Jörger and others showed that these groups are polyphyletic. This means they do not all share a single common ancestor. Some snails with gills are actually more closely related to other groups than they are to each other. This diversity has allowed snails to spread across almost every environment on Earth.

Humans have had many interesting connections to snails throughout history. In agriculture, some snails are considered pests because they eat crops. Farmers use methods like copper bands or diatomaceous earth to protect plants. On the other hand, some snails are considered a delicious food.

Cooked snails
Cooked snails

Even their mucus is used in modern skin care products. Historically, certain snails were used to create dyes. The famous Tyrian purple dye was made from the secretions of the Muricidae family. This shows how a small animal can have a large impact on human culture.

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🖼️ Images & Media (8)
File:Epiphragma einer Weinbergschnecke.JPG
Epiphragma einer Weinbergschnecke.JPG
File:Snail on the floor.jpg
Snail on the floor.jpg
Snail eating a leaf.ogg
File:Slug 02.jpg
Slug 02.jpg
File:Snail-wiki-120-Zachi-Evenor.jpg
Snail-wiki-120-Zachi-Evenor.jpg
File:Cooked snails.JPG
Cooked snails.JPG
File:Mochesnail.jpg
Mochesnail.jpg
File:Dead Snail.jpg
Dead Snail.jpg
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