Difference Between Slugs and Snails

Slugs and snails are two identical looking gastropods, belonging to the phylum Mollusca of the animal kingdom, capable of living on land (alongside water). With great diversity, there are over sixty thousand species of slugs and snails in the world today, varying in size from microscopic to large, clearly visible ones.

While they both belong to the same taxonomical class and phylum of the kingdom animalia, slugs and snails are two different creatures with numerous biological and physical differences. The basic and the most visible difference between the two is their external structure and appearance. The long body and two pairs of retractile tentacles of a slug are very much similar to those of a snail, but the external shell, prominent in the latter, is absent in the former. Instead, the slugs have an internal shell, underneath the skin which they use to protect their body. Furthermore, diversity is very high among snails as compared to slugs. Slugs and snails also differ in the amount of mucus secreted, as the former secretes much more mucus than the latter. Moreover, slugs are more vulnerable to desiccation as compared to snails.

Besides these differences, slugs and snails share a lot of similarities as well. Both of them have coiled body structures, muscular feet and light sensory tentacles. They both can live on land as well as in aquatic ecosystems. Moreover, both slugs and snails are hermaphrodites, that is both male and female reproductive organs are present in the same animal. Both slugs and snails also breathe through an opening in their mantle, called a pneumostome.


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    Slug is a common name for a terrestrial gastropod mollusc that usually has no shell (or a very small one). Slugs live both on land as well as in sea, and there is even one specie that lives in freshwater. The term slug is usually used to describe the land slugs, whereas the slugs living in sea or fresh water are usually referred to as sea and freshwater slugs respectively. Slugs are detritusvores i.e. they eat fungus and dead leaves.

    Image courtesy: wildaboutbritain.co.uk

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    Snails are highly diversified shelled gastropods, with more than 25000 species in the world. The snails typically have coiled bodies covered with a similarly coiled shell. However the size, colour and shape of snails vary drastically among species. The snails use this coiled shell to hide in when they are alarmed. Snails mostly live in sea but some species have been located on land as well in freshwater.

    Image courtesy: animals.about.com

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