Have you ever seen a snail without its shell? Well, I haven’t exactly except when they are about to be eaten! Snails go everywhere with the snail shell on their back and I often wonder if it’s really necessary for these small crawling creatures. I cannot imagine going everywhere with my bed not alone my room or to make matters worse, the entire building.
Is the snail shell a curse or a blessing? Why do they have shells? Of what importance of the shell to the snail? Can a snail be without a shell just like their cousins, the slugs? Let’s take a closer look.
In some quarters, snails are banned and seen as pests destroying valuable cash crops and vegetables (snails can eat over 50 types of plants and fruits) and an amazing delicacy in other quarters.
Some people, culture, religion detest the snails and would not want to have anything to do with them either dead or alive and there are those that would carefully pick up a snail when in their way to avoid crushing them (a typical example is my Dad).
Yet everyone has the same conclusion when it comes to the snails movement; snails are slow paced creatures!
Most land snails are terrestrial gastropod mollusk that possesses shells. They are usually found in damp, wet and cool areas and eat varieties of plants and fruits. Land snails are reared in captivity majorly for food by humans, and also as raw material supplier of slime for pharmaceutical and cosmetic industries.
Snails and slugs both belong to the gastropod family but the shell makes the difference. Snails have spiraled shells while slugs do not; at least that we can see externally. The snail shell varies in size, colour and shape depending on the specie and habitat of the snail.
Slugs on the other hand do appear to be without shell but under microscopic view have been seen to have remnant within the mantle. Others have shells that cannot just host the slugs body unlike their snail cousins.
This is not exactly a scientific article so I would try not to bother you with too many terms but lets see if the shell is really necessary for the snail!
Characteristics Of The Snail Shell
The snail shell is an artistically coiled structure with variations due to the species of the snail.
Movement Of The Snail Shell
The snails with dextral shells make their shell look as if they want to make a turnabout from their centers in a clockwise direction, from the right side but its actually an anti-clockwise direction. Snails with shells that turn the other way due to random natural influences move in the opposite direction; clockwise.
Some snails have sinistral shells such as the Roman snails with left-turning shells earning them the title ‘snail kings’ in the German-speaking regions. They are very well sought after and highly prized among collectors because there is only one sinistral shell for every 10 million snails with dextral shells!
No scientific reason can be attributed as the reason why snails have shells that move to the left or right especially as over 90 percent of the snails generally have dextral shells. However, it may be as a result of mutation, or, sometimes, hereditary from the maternal genome.
Composition Of The Snail Shell
The hard, solid spiral-shaped coloured structure carried on the back of the snail is the snail shell. The snail shell has a composition of calcium carbonate obtained from the food intake and rich soil in their habitat. The calcium carbonate attributes to their shell hardness; the more the calcium carbonate, the harder the snail shell and vice versa.
The central layer of the snail shell is called the ostracum which is made up of calcium carbonate crystals, the bottom layer is called the Hipostracum and the most superficial layer is called the periostracum, which is made up of several proteins.
New hatchlings at birth have transparent shells forming from the visceral hump along its lineal axis. The shells gets thicker and stronger as they age with the aid of the glands filled with calcium carbonate distributed across the snails body.
This results in the snail shell having two layers of calcium running horizontally and vertically. This stabilize the snail shell and make it less fragile and it grows right at a slow pace until the animals reach sexual maturity.
Shape Of The Snail Shell
There are varieties in the shape of snail shell due to the specie, their habitat and what survival skill they need to survive. These shapes include cone, round with more varieties in these two although majority of the snail shells are spiraled due to the manner in which they grow their shells. All snail shells can host all of the snail body; there is no small shell and big body.
Colour Of The Snail Shell
Snail shells are usually coloured with fringe designs ranging from brown to yellow. This array of brilliant colours make snail shell a delight to artists making them crafted into beautiful pieces of arts and other ornamental purposes.
Land snails develop their colours due to their genetic makeup and also due to the habitat. It is good to look different from your neighbor; don’t you think? Some snails can have a slight genetic drift and have a slightly different colour. A colour can spread in a population and they are all known to have that particular colour.
The colour of a snail shell can also be as a result of environmental conditions such as heat. Snails originated from the sea and few have migrated from the water bodies to become terrestrial.
The temperature on land is definitely different from water bodies therefore, snails have to adapt to this. Snails produce heat shock proteins which protect them and invariably create a variety in the colour of the shell.
Importance And Uses Of The Snail Shell
The primary and most known use of snail shells is protection of the snails internal organs which are located in a visceral hump. Snail shells have other uses both to the snail and human beings a well.
Importance Of Snail Shell To The Snail
- Snail shell provide support for the snails soft body structure.
- The snail shell protects their internal organs.
- Snail shell offers protection against predators such as rodents and reptiles.
- Snail shell provides protection against threats and enemy attack.
- Snail shell offers protection against the sun.
- The snail shell prevents the snails from drying out during hot weather.
Importance Of Snail Shell To Man And Animals
- Snail shells are crushed and mixed with the soil in soil treatment for snails use.
- Snail shells are also used as calcium supplement in livestock feeds.
- Snail shells are used in preparation of escargot dishes.
- Snail shells are used in the production of ceramics.
- Snail shells are used in shell arts for ornamental purposes.
Conclusion
Snail shells are important to snails survival just as the basic needs of man; food, clothing and shelter. They cannot survive or live to their potential without their shells.
From the start of life till they reach sexual maturity, snail shells grow and its stronger based on what the snails eat.
Fragile shells means the snails are poorly fed therefore snail farmers should take adequate note of what they feed their snails.
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