Article
Common Snail or Garden Snail
Latin Name: Helix aspersa
The word snail is a common name that can be
used for almost all members of the molluscan class Gastropod which have coiled
shells in adulthood. Snails which do not have a shell or only a very small shell
are usually called slugs. Snails which have a broadly conical shell which is not
coiled, or appears not to be coiled, are most often known as limpets.
|
|
|
 Click on image
to see larger version. One of the most well-known of all terrestrial
molluscs, is the Common or Garden Snail. It is native to the Mediterranean
region of Western Europe as far north as Britain, however it has been widely
introduced elsewhere in the world.
Because of their moist skin, snails are most active in damp weather and at
night. As a part of their diet they often feed on garden plants and for this
reason are considered by some to be pests.
During periods of activity the head and foot
emerge as well as the 4 tentacles on their heads, these can be retracted into
their heads. The mouth is located beneath the tentacles and contains a chitinous
radula, a sand paper type surface which it uses to scrape and manipulate food
particles. Their muscular foot contracts to move the them and secretes a mucus
to facilitate locomotion by reducing friction against the surface. It's top
speed is 1.3cm per second (47 metres per hour). They have a strong homing
instinct and will return to a regular hibernation site.
They are hermaphrodites and have both male and
female organs - although they still need another snail to mate with. When two
snails meet mating is initiated by one snail piercing the skin of the other with
a calcified 'love dart'. The exact purpose of this dart is now fully understood
but it seams to stimulate the other snail into exchanging packets of sperm.
After mating they produce eggs internally which are fertilised by the sperm that
has been exchanged. It is also a food
source for many other animals including small mammals, birds, lizards, frogs,
centipedes and predatory insects. The
garden snail is closely related to the edible snail which is commonly used for
cooking in France. However the edible snails are usually farmed typically they
will be 40-55mm big and weigh 25-45 grams and are typically found in Burgundy,
France. When cooked the French way normally with garlic and parsley butter. |
Identification
Common or Garden snails
have a pale grey moist skin. At the front end are four tentacles, the shorter two
are for feeling and the longer pair are eye stalks. The shell of these snails is
light brown with darker brown bands following the spiral of the shell. The shell
colouration varies in its intensity from pale yellow to almost black, it can
also have stripes, flecks or streaks.
|
Animal
Facts
In Britain: All year round
Life Span: About 2-3 years.
Statistics:
The adult bears a hard thin calcareous shell 25-40mm in diameter and 25-35mm
high.
Habitat: They live in varied habitats and
are often found in gardens, parks, forests and dunes.
Food: They are herbivores and feed on
decaying vegetation, algae, fungi, lichens and plant leaves. They have a
symbiotic bacteria in their crop to allow them to digest cellulose - they have
been known to feed on damp paper and cardboard.
Breeding: Most snails can mate when they
are a year old. They mate late spring or early summer. A month after mating the
snail lays about 100 small white eggs in a nest underground in damp soil. If
conditions remain right these will hatch after about 14 days. Newly hatched
snails have small fragile shells and take about two years to reach maturity.
They will lay eggs as often as once a month.
|
Conservation
Status
Least Concern
Not Evaluated |
Distribution: They are common and widespread in Britain and Europe.
Behaviour:
Their moist skin means they are most active in damp weather and at night. When
conditions become too dry, they retreat into their shell and seal the entrance
with a parchment-like barrier known as an epiphragm. When sealed away like this
the snail goes into a state of suspended animation and can survive for several
months without water. They can often be found in this state under rocks in
gardens or on a wall in a sheltered corner.
Common snails feed by scraping a ribbon-like tongue covered in horny
teeth called a radula, over their food. This allows them to scrape algae and
lichen from the surface of rocks and walls. You can sometimes see the trails
they leave behind as they eat their way through the algae on a damp wall.
Conservation Status: They are very common and have not be evaluated.
See Also:
We have a project page on
photographing snails
with very many more pictures of the Garden Snail.
For more information on snails, both land
and water snails, snails in cuisine (popular in many parts of the world) and
cultural depictions.
Wikipedia Link.
Snail
Racing
is a sport - find out more. The World Snail Racing Championships
take place each year in July, at the Cricket Field in Congham, Norfolk in
the UK.
See this link
for
the winners of the latest competition.
|
