Snails

Snails are very strange and mysterious animals. They belong to a group
of soft-bodied animals called molluscs such as oysters, clams and other
shell-fish. They are very diverse: some live on land, some in the sea, as
well as fresh-water.

The soft body is enclosed in a hard shell for protection.  The shell is
made of calcium, so the snail needs to eat large amounts of calcium. If
you disturb the snail, it will immediately hide inside its shell.

They have two pairs of tentacles and their eyes are located on the tip
of the longer pair. (Snails that live in water have them at the base not
the tip of the tentacles). The shorter pair is used for smell and feel;
you must have seen the snail "sniffing" around with it.

Snails are usually more active at night. They mostly eat plants and
fruits and can seriously damage crops.

The land snails (pulmonates) breathe air into a small cavity that has
numerous blood vessels, like a lung. The lung opens to the outside through
a hole called a pneumostome through which it both inhales and exhales !
Many of these snails can also live in water, provided they come up to
the surface to breathe in air once in a while. They can also breathe
through their skin.

The snails which live in water cannot survive on land. They
have either one or two gills called ctenidia that are the gas exchange
organs. They belong to the paraphyletic group. Since they do not need
air to breathe, they may even live in the depths of the oceans.

The snail is both male and female. Therefore, it can produce sperms and
eggs at the same time ! It is called a hermaphrodite.  Snails take about
2 years to become adults.

The snail moves by creeping on a flat foot that is under the body. It
often produces a slimy mucous to reduce friction so it can walk more
easily. It can take 3 minutes to cover a distance equal to the
length of your foot, roughly 1 mm/s. The slow speed of a snail is
proverbial; it is even slower than a tortoise. This may not always be a
bad thing, as the poet Kobayashi Issa said in the haiku:

katatsuburi
soro soro nobore
Fujinoyama

Translated by R. H. Blyth:

O snail
Climb Mount Fuji
But slowly, slowly.

Picture: Common or garden snail
Back Inside Cover:  Grapevine snail