Table of Contents

Introduction

Roman snails only have one foot, but thousands of teeth. When mating, they are not either male or female, but both, and at the same time. Roman snail biology is full of secrets and interesting facts ... More...

Biology

Body Parts and Organs (Morphology)

While outside of a Roman snail's shell only foot and head can be seen, there are also parts of its soft body that always remain in its hard, life-less shell... More...

Feeding and Nutrition

Roman snails are plant eaters - herbivores. Their rasp tongue (radula) with thousands of almost similar toothlets is typical for molluscs in general. Snails and other molluscs thus are among the rare invertebrates that are able to chew their food, more than simply ripping it apart ... More...

Digestion and Excretion

Digestion in Roman snails does not happen like it does in humans: The stomach, for example only is a blind sack, where food is dammed up to be better digested. The main digestive gland is often called the snail's liver, but serves considerably more purposes than simply producing digestive fluids, it also digests food and stores nutrients, it even retrieves calcium carbonate from a snail's food.

A snail's excretion happens it its kidney. Here waste matter mainly made from nitrogen compounds is filtered from the blood, but at the same time water is retained, so the Roman snail finally excretes a viscous paste of ureic acid. More...

Respiration and Circulation

All Roman snails are nobles they have blue blood. That is, however, less because of their descent of an ancient noble line, but because of their blood pigment: Many snails use haemocyanin, which works on a copper complex turning blue in the oxidized state ... More...

Nervous System

The Roman snail's nervous system has evolved from a ventral rope-ladder nervous system, similar to that of segmented worms (Annelida). The Roman snail's nervous system, though, has evolved considerably since its rope-ladder times: The nerve knots (ganglia) formerly dispersed in the body have concentrated in a ring around the gullet, so that this could even be called the snail's brain ... More...

Senses and Sense Organs

A Roman snail only has got two types of sense organs: Its eyes and the equilibrium organs near the ganglion ring around the gullet. Numerous specialised nerve cells are, however, dispersed over the body surface and provide the snail with information on touch, temperature and humidity. Cells on taste and smell mainly are located on the snail's lips and tentacles ... More...

Reproduction and Development

Courtship and Mating

Roman snails are hermaphrodites - their single genital apparatus disposes of a genital organ, (gonad) producing sperm cells as well as egg cells and thus also called a hermaphroditic gland. Besides there are numerous auxiliary organs and genital ducts. Before two Roman snails actually mating there is an extensive courtship, during which even a love dart may be applied, the role of which only has been discovered some years ago... More...

Egg Deposition

The fertilisation of eggs happens independently from mating, only directly before oviposition: When the snail has obtained a suitable place for depositing its eggs, it begins to dig an earth hole in which it then lays its eggs. When finished, it closes the hole with earth and leaves the eggs alone ... More...

Development

From the fertilised egg cell a young snail develops. Roman snails, other than many aquatic snails, do not develop by a free larval stage, but their complete development takes place inside the egg. The hatching juvenile looks quite similar to an adult snail. But until it reaches maturity, there is a long dangerous life lying before it ... More...

Hibernation

In Central Europe, Roman snail, that can reach more than 20 years of age, must be able to endure the frosty winter climates. Thanks to an amazing variety of adaptations, physiological as well as in behaviour, Roman snails can survive temperatures considerably below zero... More...

Aestivation

Not only winter's cold, but also heat and dryness in summer may be harmful to a Roman snail, which is much better adjusted to humid weather. It can, though, endure such dry times during resting periods called aestivation... More...

The Shell

A Roman snail's shell consists of hard, resistant lime (calcium carbonate). Until maturity the shell grows together with the snail's body, because the snail keeps attaching further lime material near the shell mouth. Besides, the shell wall is also thickened by attaching shell matter from the inside. As after maturity this is the only shell growth left, there are old Roman snails with amazingly thick and resistant shells. Should there be shell damage the snail may even be able to repair it. By form and colour of its shell the Roman snail can also be distinguished from its relatives, the other helicid snails... More...

Systematics

Classification

Biological systematics distinguishes nomenclature (naming) and classification into a biological system with firm rules. The Roman snail (Helix pomatia) together with its relatives, aside from Helix also from the genera Cornu and Cantareus, as well as with farther related genera like the banded snails (for example Cepaea nemoralis) and the copse snail (Arianta arbustorum), is counted among the helicid family (Helicidae). Those belong to the order of Stylommatophora, the sub-class of Pulmonata and finally of course, to the snails and slugs (Gastropoda), one of eight classes in the mollusc phylum (Mollusca). More...

Identification

Identifying snail species with accuracy in a correct scientific way is far from easy. Helix pomatia is clearly not the only Helix species. Besides there are at least two other large helicid snail species in Central and Western Europe, introduced from other countries. Especially on the Balkan Peninsula, as well as in Asia Minor, there is a large number of Helix species and related groups. So the necessary identification can happen using shell characters, or by dissecting snails and examining them anatomically. As a last resort there finally may be a molecular genetic examination... More...

The Natural Habitat

A Roman snail is a lime-loving humid air animal. It occurs preferably on lime rich soil with abundant vegetation, such as on forest rims, bush and hedge land. Though sometimes appearing in gardens and agricultural areas (it is called vineyard snail in different languages) the Roman snail cannot be considered as a garden pest. Because of destruction of its habitats and excessive picking of snails for marketing, the Roman snail today has become so rare, that it cannot inflict any damage and is generally placed under government protection. Because of the often applied herbicides, in vineyards today there are very few "vineyard snails"... More...

Distribution

Helix pomatia is a continental snail species, in contrary, for example, to its relative, the brown garden snail (Cornu aspersum), which occurs mainly near the coast and in oceanic climate. Today it is assumed, that the Roman snail has only been able to settle in Central Europe because of the post-glacial human settlements clearing the adjacent forest. Also, there has been distribution of Roman snails directly by man, which is why it is called Roman snail... More...

Economy

The economical importance of molluscs to man can be retraced as far back as prehistoric times. From excavations it has been known, that molluscs were collected at that time already, first mussels from the sea, later also snails. Today snails are not only eaten but also used for pharmaceutical research.

Snail Farming

As it is too rare today to be picked from nature to be sold, the Roman snail is among the snail species cultivated on snail farms. Economical (and ecological) snail farming is the only ecologically feasible way to produce a sufficient amount of snails to satisfy the market. There are different methods of snail farming, most of them mainly from France and Italy. There is competition, though, by snails from Eastern Europe (Poland), the Balkan and Turkey, where snails still are picked, no matter what the ecological consequences. More...

History

Raising snails has accompanied man through an ever changing history. In the Middle Ages snails were a welcome lent food for monks as well as for peasants and nobles alike. Napoleon had hibernating lid snails taken with his soldiers as a natural conserve on his campaigns. In the 18th century snails from Swabian snail gardens were marketed as far as Vienna down the Danube River by special transport barges, the Ulm boxes. Today, snails are considered an expensive delicacy, but there is also a development towards the consumption of an old historical produce of nature. More...

Reference

Literature

Literature index.

Links

Gastropod links.