Snails are invertebrate creatures that are characterized by their slow movements and by having a shell that has a spiral shape. Join us to learn everything about them.
The snails can be easily found in damp places and move crawling on the ground. It is very easy to see them just after having rained and at the slightest danger; they shrink and hide inside its shell. These little shelled gastropods are smarter than many people think and next we will know more about them.
Table Of Content
Main Characteristics
The common snail or burgajo is a gastropod mollusk, this last word of Greek origin meaning stomach-foot, since they walk lengthening and contracting their stomach on the ground. Snails are herbivores but not all of them eat the same thing, since depending on where they are they will have access to different types of food.However, the leaves, fruits, vegetables and sprouts can be mentioned as their main foods
By natural instinct, they look for those foods that are rich in calcium, since they need it to keep their shell hard and strong. These nice mollusks can´t eat sugar or salt, since their body is not able to process them and they would die, which is Something that you should keep in mind if you want to have them at home as a pet.
There are many types of snails that are classified according to their habitats: aquatic or terrestrial. The former are adapted to live in the sea or in fresh water, and the latter live exclusively on land, although in humid areas. Being mollusks implies that they lack skeletons and internal bones, but snails are not unprotected. The gastropods belong to the phylum Mollusca (or molluscs) a classification of invertebrate animals with a soft, unsegmented body, sometimes covered with an exoskeleton or shell. This phylum, Mollusca, includes animals such as squid (int), octopus, clams and cuttlefish, among others. Snails and slugs are both gastropods. Therefore, they are closely related, regardless of the fact that slugs lack a protective cover.
The snails´ distinctive physical feature relies on their spiral shaped shell. It is a hard structure made up of calcium carbonate, which protects their internal bodies and organs. Among these organs are their lungs since land snails breathe air from the atmosphere that then passes to such organ to obtain oxygen. This is one of the main differences with aquatic snails, since only a few species of them breathe air.
Snails that breathe using a lung belong to the Pulmonata group. While snails with gills also form a polyphyletic group. Thus, snails with lungs and snails with gills form a series of taxonomic groups that are not necessarily more related to each other than those related to other groups.
Both snails that have lungs and snails that have gills have diversified so widely throughout time that some species with gills can be found in the ground and numerous species with lungs in fresh water. Even a few marine species have lungs. As for Terrestrial snails they can´t hear anything, but they have eyes and olfactory organs. They use their sense of smell to find food, which is their most important sensory organ.
Their body is divided into head, feet and visceral mass which is covered by a fleshy mantle or veil that has some specialized cells, that are responsible for segregating semi-liquid calcium carbonate. This substance hardens when in contact with water and forms or becomes part of their shell. In turn, the shell is made up of three layers. The outer one called periostracum is a thin layer composed exclusively of organic material called conchiolin (combination of protein and polysaccharides) which protects the innermost layers from the attack of organisms and other environmental hazards.
Then follows the middle layer called tracum formed by prismatic crystals of calcium carbonate (CaCO3), in the form of aragonite or calcite. Finally, they have a pearly inner layer, which is the one that is in direct contact with the skin of the animal and receives the colloquial name of nacre shell and it is an organic mixture of layers of concholine and aragonite crystals. Most snail species have an attached structure called operculum, which is responsible for closing the shell once the snail has withdrawn inside it. Although as they grow, the whorls (turns of the spiral in the carapace) become more abundant, it is almost impossible to determine their age based on it. This is because they have a different development according to biology and species. In addition to that the temperature of the water influences in this process, because the cold water doesn´t allow the development only causes that the snails swell.
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¿Can Snails Change Their Shells?
There are animal species that are able to replace lost parts of their body, such as starfish , crabs that shed their shells, among others. But land snails can´t change their shell, although it increases in size and hardens as they grow. They live and take advantage of it to defend themselves, hence its relevance.
They can´t replace it fully, but they are capable of regenerating any breakage, breach or imperfection that their shell may suffer. The evolution has endowed the snails with the necessary mechanisms to replace or fix defects in what is their home. If a snail fails to repair it, it may be because it suffers from some disease, doesn´t have enough strength or lacks the calcium to make the arrangement. The shell, besides being fundamental for their life is a living part. That is why any alteration will be a trauma for them. But what happens if a snail loses its shell altogether? Inevitably the snail will perish, without defenses to protect itself from the inclemency of the weather, the predators´ action and without capacity to conserve the humidity that they need, the snail will be defenseless.
Size
Land snails vary greatly in size. Although some of them are only a few centimeters long and weigh only a few ounces, there are land snails that reach almost 12 centimeters, like the giant African land snail, an endemic species of Africa.
Displacement
Snails can move thanks to a series of undulating muscular contractions that cross their body´s lower portion. They move slowly because they alternate the body´s contractions and elongations generating small movements. When they move they produce mucus which helps them in locomotion, reducing the friction that can occur with the soil. Likewise, this mucus helps the animal’s thermal regulation, reduces the risk of suffering injuries and avoids the external aggressions of bacteria and fungi.
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Species without Shell.
There are some specimens such like the land slugs that don´t have a shell or have only an internal remnant. According to the needs of evolution and adaptation to the environment that surrounds them, there are some species that have been modified according to the climatic conditions and the needs of the animals themselves. But lacking a shell, they use other types of protection mechanisms, which include releasing substances that are toxic and lethal to the animal that eats them. Also because of these toxins they can be inedible by predators.
These types of snails (slugs) get their poison by feeding on sponges and cnidarians by incorporating their toxic substances into their body. Their system of teeth, or radula, is modified to throw poisonous darts to their enemies, capable of paralyzing them. They can also use other means such as mimicry, acquiring the shape and color of the environment that surrounds them, managing to get confused even with coral reefs. On the other hand they can be aposematycs, which is the condition in which their colors are striking to warn other animals that they are poisonous. We invite to read our article sea slugs to learn about different types of slugs
here they are
Characteristic Behavior
It is very common for snails to form groups made up by individuals of the same size and age distributed in the areas where they live. During the day, it is very difficult to see snails wandering somewhere. They seek refuge in damp places, such as under the trunks of trees and stones, or under pots and terraces. During the night, they go out to feed.
When winter approaches, many species carry out hibernation. To achieve an effective rest they retract in their shell and seal it with the operculum. There are snails that gather in a large group to hibernate all together, while others prefer to bury themselves in the ground. They reach sexual maturity at three and a half years, when their organisms begin to form aggregations.
¿How Snails Reproduce?
The snails´ reproduction can vary according to the species. In some cases the fertilization can be carried out when the specimens interbreed or they can release the gametes to the water for their subsequent crossing, generating masses of eggs or larvae. There are cases of snails that can change sex, (phenomenon called protandry), having a single specimen both sexes (hermafrodytes) and thus reproduce by its own.
In the species that have a process of internal fertilization, the female creates a long protective tube after three weeks where she can hold between 300 thousand and 600 thousand eggs that they then expel to develop. Each female can have up to two or three sets during a month. After five days the eggs hatch giving rise to a larva that is called Véliger with a length of 200 micas. After 30 days, the larvae begin a metamorphosis process where they give rise to a young snail of two millimeters in length. After a year, the snails can measure 14 centimeters and when they reach three years they will begin to form the lip, which will be a sign of their sexual maturity.
¿Can Snails Be Eaten?
Snails are edible and in some countries such as France, they are the basis of some dishes that gastronomes define as exquisite. The ancient Romans were lovers of these mollusks: they were raised by feeding them with aromatic herbs and then cooking them in white wine, in order to make them even tastier. One precaution that should be taken before eating them is to keep them fasting during a week so that they can eliminate what they have eaten previously, since they ingest poisonous herbs and fungi for humans.
Nutritional information
Snails are low in calories and high in protein. A simple serving (3-ounce) contains only 76 calories, or about 4 percent of the calories you are allowed to eat on a 2,000-calorie diet. Like any other animals´ protein theirs is quite complete, which means that it contains every amino acid you need to get from your diet. Snails also contain small amounts of carbohydrates and fat, 2 grams and 1 gram, respectively, to be exact.
Iron
In addition to getting protein from them, snails will also provide dietary iron, which is an essential mineral especially for your blood. This mineral is quite useful for carrying oxygen throughout your body. Iron is also important for your active lifestyle because it supports energy production, and is also crucial for immune health. A serving of snails has about 3 milligrams of iron, which covers between 17 and 38 percent of the iron you need for the day.
Zinc
In terms of immunological health, snails also enhance your immunity because of their zinc content. Zinc’s most important role in your body is making up the structure of various proteins and enzymes – and it’s so important for the proper functioning of your immune system.
. Zinc also helps with cell growth, healthy cell development, and a range of other processes your cells and tissues need to work properly. A serving of snails provides 0.9 milligrams of zinc – between 8 and 11 percent of your daily needs
Different Types of Snails.
There are about 55000 species of snails that have been able to adapt to live in different environments, which have made them very abundant all over the world. Next, we will learn about the main ones.
Giant African Snail
Its scientific name is Achatina fulica or African giant snail. These snails are herbivorous and large size. Its shell reaches up to 20 centimeters in length and 7-10 centimeters in height. An adult individual weighs about 32 grams. Their body has two short tentacles and other two long where the eyes are located. Narrow conical shape and appearance, the shell may have 7-9 spirals (whorls) visible on its surface. Their color is not always the same, but it depends on their habitat´s environmental condition. In general, it is slightly dark or reddish brown with yellow vertical stripes.
African snails are included in the list of 100 most damaging invasive species of the world, since they easily adapt to life in regions outside their natural distribution area. They inhabit mainly in warm and humid climates. Although it is a native species of East Africa, African snails have been introduced to many parts of the world over the years and today you can find them in African countries like Ghana, Ivory Coast and Morocco; as well as in Hawaii, Australia, Islands, many Caribbean countries and in several Islands and regions of Asia, the Indian Ocean and the Pacific such as China, Bangladesh, Japan, Indonesia, Zealand, , Fiji and Vanuatu. To summarize, the giant African snail is located on all continents except for Antarctica.
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Garden SNAIL ( Helix aspersa)
These snails are famous because of their slowness, and are also called common snails. They are small mollusks, with a shell of 2.5-3.5 centimeters in height and 2.5-4 cm in diameter. They have a spherical shape and a slightly rough surface, with around 4 or 5 spirals. Not all individuals have the shell of the same color. In some of them it is dark brown, but in most it is brown or clear with a golden hue. Moreover, they have several Brown or yellow veins. The shell has a large opening whose edges are white.
This species is native to the Mediterranean region, but is currently in many areas, making it a species of wide distribution and presence in all continents, with the exception of Antarctica. You can find individuals of Helix aspersa in the lowlands of Great Britain, in the Mediterranean, in the West of Europe, in North Africa including Egypt, in the Iberian Peninsula and in the East of Asia minor, including Turkey. It was also introduced in the United States, where it has thrived in a few regions.
Roman Snail, (Helix pomatia)
The roman snail, Burgundy snail or vineyard snail, is a gastropod mollusk and one of the most well-known and widely distributed snail´s species in the world. They are big snails whose shell measures about 3-4.5 centimeters in height and around 3 to 5 centimeters wide. They a brown hue, 3-5 bands or stripes and 4-5 spiral.
They are distributed in many parts of Central, Southeast, West, East, North and South of Europe, in countries such as Germany, Belgium, Finland, France, Ukraine, Norway, Poland, Italy, Hungary, Austria, Estonia, Albania, Britain, Switzerland, Netherlands and Russia. Given the large number of areas in which they are located, the Roman snails are adapted to life in various types of habitats. In general, they prefer open temperate forests and hedges, vineyards and scrubland areas.
Curious Facts about Snails
Although it seems incredible, there are people who have managed to train the snails. They are able to obey certain instructions. But at the cost of a great dose of patience, of course.
- Snails´ races are very popular in some countries. People usually pay huge amounts of money in bets.
- The largest snail ever found was a land snail that weighed 800 grams and 39 centimeters in length. It was found in 1976.
- Another gastropod, quite similar to the snail, is the slug. It does not have a shell, and feeds on decomposing animals and leaves. They live in fields and orchards, where it causes havoc among plants.
believe it or not
Snails and the Human Beings
These small and weird creatures are quite related to human beings in several areas which we mention following:
As food
As already mentioned, in French cuisine edible snails are served, for example, in Escargot à la Bourguignonne. The practice of raising snails for food is known as heliciculture. For cultivation purposes, the snails are kept in a dark place in a cable cage with dry straw or dry wood. Coppiced wine grape vines are often used for this purpose. During the rainy season the snails come out of hibernation and release most of their mucus on dry wood / straw. After being cooked their texture is slightly chewy.
In addition to being savored as gourmet food, several species of land snails provide an easy-to-harvest protein source for many people in poor communities around the world. Many land snails are valuable because they can feed on a wide range of agricultural waste. In some countries, giant African land snails are produced commercially for food. In Bulgaria, snails are traditionally cooked in an oven with rice or fried in a pan with vegetable oil and red paprika powder. However, before they are used for these dishes, they are boiled thoroughly in hot water (up to 90minutes) and manually extracted from their shells.
Cosmetic
Skin creams derived from snails are commonly sold for treatments against wrinkles, scars, dry skin and acne. Different research studies have suggested that secretions produced under stress by these mollusks could facilitate the regeneration of injured skin tissues. Let´s see.
- The snail slime contains nutrients such as hyaluronic acid, glycoprotein, proteoglycans and antimicrobial and copper peptides, all of which are commonly used in beauty products and have been shown to be beneficial for skin. These elements help to protect the skin of the snail against damages, infections, dryness and UV rays
- Cosmetic snail slime is usually obtained from common garden snails that grow in the laboratory or Cornu Aspersum (formerly Helix Aspersa), which is considered an agricultural pest
- Snail mucin is best known for its anti-aging properties. It helps stimulate the formation of collagen and elastin, protects the skin from free radicals, soothes the skin, repairs damaged tissues and restores hydration. It can be used to treat dry skin, wrinkles and stretch marks, acne and rosacea, age spots, burns, scars, scrapes and even flat warts.
- The filtering of snail secretion is widely used in Korean beauty products, such as serums, facial masks, moisturizers and fade creams. Actually, most products are not as cool and sticky as you might think. Most of them have a neutral appearance, smell and texture.
- Snail spas are very popular in Thailand and have reached important Asian beauty-conscious countries, such as Japan and Korea. During the spa session, the live snails are placed on the client’s face and allowed to slide.
- DIY snail spas or snail slime products are not recommended. Remember, the snails used in a responsible spa center or in beauty products are professionally grown and the snail slime is professionally purified, while those in your garden are not.
- Hasta la vista dear readers
