About Slugs And Snails

Garden Snail (Cornu aspersum)

Garden Snail (Cornu aspersum)

People maybe surprised to know that molluscs consist of the second largest group of animals on earth after the insects, with some 100,000 species plus. Of this group the gastropods are the largest of the mollusc group, with more than 50,000 species globally. They  have been around for at least 500 million years. Their habitats can be marine, freshwater, estuarine, or terrestrial. Included in this class are the shell covered snails. limpets, sea hares, and the shell-less slugs.

Slug Eggs

Slug Eggs

The body of the snail consists of a large muscular foot, a visceral hump which is contained within an asymmetrically coiled shell (a univalve) a head with eyes and tentacles, and a mouth that contains a rasping tongue used to remove, crush and grind food. Most species of snail are herbivores, whilst others feed on live prey or carrion. They are mainly active at night so their bodies do not dry out in the sun, and during the day they hide in dark, damp places. Those with shells which not only give them some protection against predation, but also protection from desiccation, hide within them and seal themselves against rocks, stones, or vegetation.


Large Red Slug (Arion (Arion) rufus)

Large Red Slug (Arion (Arion) rufus)

Order: Stylommatophora (Air-breathing Terrestrial Slugs & Snails)
This taxon, now considered to be a clade, is a very large group of pulmonate (air-breathing) land snails and slugs. They are characterised by having two pairs of retractile tentacles with eyes located on the tips of the larger tentacles.


Wandering Pond Snail (Radix peregra)

Wandering Pond Snail (Radix peregra)

Order: Basommatophora (Freshwater Snails)
In this order are the air-breathing land snails which are found in ponds, ditches, streams, rivers and shallow lakes. They are characterised by having their eyes located at the base of their non-retractile tentacles, rather than at the tips, as in the true land snails in the order Stylommatophora. The majority of basommatophorans have shells that are thin, translucent, and which are fairly colourless.


Purple Topshell (Gibbula umbilcalis)

Purple Topshell (Gibbula umbilcalis)

Order: Neogastropoda (Whelks, Cones & Tritons)
These gastropods are mainly deposit feeders or predators. They all have a well-developed siphon for detecting prey. The larger bottom-dwelling carnivores commonly feed on bivalve molluscs, other gastropods, sea urchins, polychaete  worms, and even fish. They will often burrow into the sand to reach their prey.


Dog Whelk (Nucella lapillus)

Dog Whelk (Nucella lapillus)


Order: Neotaenioglossa (New Gastropods)
This order of mollusc is believed to have evolved around 70 million years ago during    the last days of the dinosaurs. They are characterised by the possession of only one gill, one auricle, one kidney and by siphon. This order is generally considered to be the most advanced of the prosobranch molluscs, which include the familiar whelks.

Flat Periwinkle (Littorina obtusata)

Flat Periwinkle (Littorina obtusata)

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21 thoughts on “About Slugs And Snails

    • It’s amazing how many there are, and I think I have most of the terrestial ones in my garden! Yes, Arion species causes a lot of damage. Thank you for your comment, Gunnar 🙂

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  1. People maybe surprised to know that molluscs consist of the second largest group of animals on earth …. .

    What a relief. I always thought it was Manchester United supporters.

    We’ve had a lot of garden snails this year. More than I can recall since moving onto this property.
    Over here, in Jo’berg, they have a natural predator, the ‘Parktown Prawn’ (which is a species of king cricket), has been noticeably scarce for some reason, so the snails have flourished.
    I cannot say I am upset. The ”prawns” are revolting!
    Nice post.

    Liked by 1 person

    • And I thought it was West Bromwich Albion supporters, lol!

      Thank you, Ark 🙂 I have just googled your prawn and it is quite something! We rely on the frogs and toads to keep their numbers down in the garden.

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      • *Smile*

        When threatened the buggers hiss at you! I am not sure how they manage this?
        And they will often spray foul smelling fecal matter.

        No Jimminy Cricket these guys, let me tell you!

        Oddly enough, I have never seen a frog or a toad in our garden, and we have a very large pond.

        It would be nice to encounter the occasional amphibian.

        Liked by 1 person

  2. Fantastic post/pics. Thanx much. I have a photo album of snail pictures on Facebook, because i find these animals very lovely and fascinating, but my pictures are nowhere as great as yours.

    Liked by 1 person

  3. What an interesting post. Thanks! Btw, ever since we planted Pennyroyal on our veggie garden pathways we have had no snails. Perhaps a coincidence but worth trying for those who find snails are eating their veggies.

    Liked by 1 person

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