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Interesting facts about snails

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We found 19 interesting facts about snails

They are also called gastropods

Snails are mollusks and are one of the most numerous animal species in the world. In terms of species diversity, they are second only to insects. Although they originate from aquatic environments, they have also managed to colonize land. When we hear the word "snail", we most often think of the shell, which is considered to be an integral feature of the snail. Nothing could be further from the truth: there are many snails that have no shells at all. Most of them live in the oceans, but they are also easy to find on land. The largest land snail is the shellless one, which also lives in Poland.

They appeared on Earth quite early, already in the Cambrian, although there is currently debate about whether organisms of this period should be classified as snails.

These organisms had rudimentary and primitive shells. Over the next 80 million years they slowly evolved, thriving and developing many different forms in the Ordovician. The first snails populated the seas and oceans. Individuals anatomically similar to those living today arose in the Triassic and only in the Cretaceous period, 150 million years ago, did they begin to colonize the land.

The exact number of snail species is unknown.

It is estimated that there are about 85 50, but the actual number is between 120 15 and 1000 XNUMX species. To date, at least XNUMX extinct species have been identified in the fossil record.

Most snails are marine animals, and there are about 30 species.

About 24 5 live on land and about 200 6 live in fresh water. Poland is home to about 50 terrestrial species,

The snail shell has four main functions.

This is a shell that protects the soft body of the snail from external threats, protects against excessive loss of water, provides muscle strength and calcium supply.

Their shells can be right- or left-handed.

90% of snails have a right-sided shell, the rest develop left-sided shells or both right-sided and left-sided shells within the same species. There are also snails with shells in the shape of a plate or a small cone, as well as with a shell consisting of two parts.

Most snails are herbivorous, but there are also predatory and carrion-eating species.

Land animals feed mainly on plants, although there are also predators among them. Predatory land snails prey on other slow-moving organisms, so they prey on other snails or earthworms.

The snail's mouth contains a grater (radula) used for scraping and grinding food.

It is a cartilaginous structure covered with a large number of tiny chitinous teeth. It is driven by muscles. It is found in both herbivorous and carnivorous snails. The structure of the radula is not necessarily related to the species of snail and is often determined by diet. The denticles can take on a pointed shape when the snail feeds on algal tissue, but when it feeds on epiphytes (plants growing on other plants), the denticles usually have blunt ends.

However, there are snails that lack a radula.

This is the only representative of land snails. Careoradula perelegans (careo is Latin for absence). Among sea snails there are more species that do not have this organ, including all representatives of the family. It's refreshing and all representatives of the clan Clathromangelia.

Most predatory snails are species that live in seas and oceans.

They prey on snails and other snails. Scavengers feed on dead crustaceans, mollusks or fish.

One of the most beautiful and impressive snails is the nudibranch. These are shellless snails with very bright colors and a symmetrical body structure.

Some of them feed on cnidarians, whose toxins do not harm the snail. Instead, the eaten cnidarians are transported through the snail's digestive system and placed in the back of its back, where they play a protective role. These snails can also camouflage themselves to avoid being eaten, or secrete a special mucus that is released when the snail is touched. Some nudibranchs are capable of making sounds audible to the human ear. All representatives of nudibranchs are hermaphrodites, but are not able to fertilize themselves.

Snails can breathe using gills or primitive lungs.

The vast majority of sea snails are equipped with gills, and some freshwater snails also breathe with them. Other freshwater species and most terrestrial species use primitive lungs for respiration, consisting of a mantle cavity with a strong blood supply.

The circulatory system of snails is open. This means that hemolymph (the equivalent of blood) is pumped into the body cavities surrounding the internal organs.

The oxygen carrier is hemocyanin and the copper it contains. Hemocyanin is blue in color.

Snails can reproduce sexually and are hermaphrodites.

Most sea snails have two sexes, while land snails are hermaphrodites. Marine species lay externally fertilized eggs, from which larvae develop: these are either trochophores or veligers. In land snails, development is simple and adults develop from internally fertilized eggs.

The most important sense of land snails is smell.

The olfactory organs are located at the tips of the snail's antennae. Marine species, on the contrary, use chemoreceptors more often.

The eyes of land snails are located on their antennae.

However, their location varies between species: in some they are located at the tips and in others at the base of the antennae. This is not the most important sense of land snails since they are mostly active at night. The complexity of the eye can vary greatly between species: some have simple eyes that cannot display images, only the intensity of light, while others have complex eyes equipped with a lens.

Some aquatic snails are able to completely regenerate lost eyes.

These include freshwater families Ampullarii or marine representative of the genus Strombus.

The largest land snail is the black one.

It is found throughout Europe, including Poland, where it was introduced in the 20th century. This snail can reach XNUMX cm in length.

This is the largest sea snail Syrinx aruana.

This is a shell snail, the length of which can reach 91 cm and weight - 18 kg. It inhabits the waters around Australia, where it preys on polychaetes.

Since 1500, 444 species of snails have become extinct.

Currently, 18 species live only in captivity, and 69 are “probably extinct.”

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