Snails and slugs are similar creatures. They are among the most destructive creatures found in landscapes and gardens. As a Gardener, you should be aware of these two creatures. When you notice that some of your young crops are dead, there are multiple holes on your plant leaves or there are trails of slime left on the soil, best believe that these creatures visited your garden.
Although both snails and slugs are similar in biology and structure, there are still notable differences between Snails and Slugs which include:
| Snails | Slugs |
|---|---|
| The presence of external spiral shells grows bigger as they develop. | The absence of shells but have straight bodies |
| The presence of a visceral hump. | The absence of a visceral hump |
| The snails have a much thinner slime than the slugs. | The slug slime is thicker than the snail slime |
| Their big shells prevent the snails from going into different habitats. | Small enough to go into different habitat |
The slug’s mantle is an alternative for a shell which is basically an area behind its head made of thick flesh. In case a slug is not active or is frightened, it will withdraw its head into the mantle as a protection measure. They need a regular supply of moisture in their body to prevent drying out. Cool, rainy weather and fog are perfect climatic conditions for slugs.
Both snails and slugs belong to the group of animals called mollusks and are mostly found on land, trees, or in water across the globe. Some will hibernate and spend the winter underground as they are mostly small and dowdy.
Since we have written extensively about the snails in previous articles here
, we will focus more on discussing the slugs, their different species, how similar or different they are from snails, and what they feed on.
Slug Species
There are four common slug species; these include:
The Grey Field or Netted slug (Deroceras reticulatum)
These are normally 3-5 cm long. They are brown with a chain of darker blotches and veins. Some are pale with a darker central below. It feeds on almost all plants and seeds above the ground, nearly all year round.
The Common Garden slug (Arion hortensis /Arion distinctus)
These are normally 3 cm long. They are brown and striped lengthwise, mostly with yellow or orange underside, and tiny gold sports. They feed on both root and leaf crops and are a major potatoes’ pest.
The Common Keeled slug species (Tandonia budapestensis)-
These are approximately 6 cm long. They are brown or black with a yellow-orange ridge. They have colorless mucus and a pale underside. Furthermore, they live underground, eating newly drilled seeds like groundnuts, potatoes, etc. This species is very hard to control since they spend most of their time underground.
The Large Black slug and Red slug (Arion ater)
These are approximately 12 cm long. They are either orange-red or black with an orange fringe. They are less destructive to crops and the environment compared to the other species. Furthermore, they contract into a spherical shape when alarmed and may rock from side to side.
How Are Slugs and Snails Different?
While Slugs and snails both belong to the same class of creatures known as gastropods, they also have different features that distinguish them. Most gastropods are aquatic animals, meaning they live in water. Slugs and snails are the only creatures in this class that lives in both land and water.
The most common difference between slugs and snails are:
- Snail’s body is covered by a protective shell, while slugs have no shells.
- Besides lacking a shell, slugs also have no visceral hump like the snails
- Behavior and habitat- Slugs are capable of squeezing themselves into different habitants since they do not have the big shells to carry around like the snails. For instance, you may get slugs hiding under loos bark on trees or logs and stones on the ground, which is not possible for snails with their shells.
For more about snail shells, check out How does a Snail Make its Shell? Your Full Guide on the Snail Shell
Similarities
Slugs and snails have more similarities than differences, some of their similarities include:
- Both slugs and snails belong to the mollusk phylum class and are similar in biology and structure, except that slug does not have the external spiral shell identified with the snails.
- Both slugs and snails enjoy feeding on plants, dead animal materials, worms, and their own depending on species.
- Both can be kept as pets and also eaten by human depending on species and the region one comes from.
- Both snails and slugs are mostly nocturnal and will go out in the evening hours or dark days. They both do not thrive in dry environment; hence they will try as much as possible to remain in dump environments.
- Both creatures have two long tentacles with an eye on the tip of each tentacle.
- Slugs and snails are both eaten by toads, snakes, birds, beetles, and turtles.
- Both slugs and snails move by gliding on a foot. As they move, they make a slimy fluid on the surface called slime that help them follow the path back to their feeding sites and tunnels.
- They both need regular supply of moisture in their body to prevent drying out, defining their major dwelling in dump moist environment.
- Both snails and slugs produce mucous that protect them in case they pass through sharp objects and help them preserve moisture in their bodies while travelling.
- Both snails and slugs are hermaphrodites; therefore, they are all capable of laying eggs after mating and typically hatch from eggs.
- Both snails and slugs are viewed as pest since most species evade crops and trees destroying and feeding on them. They can destroy crops completely by feeding on the fruits and plants, including their leaves, stems, and roots.
- Both snails and slugs are source of proteins. They are both considered a delicacy in certain regions like France, where people feed on them.
- They are generally know as slow-moving creatures because of the manner in which they move and their small size bodies.
What is the difference between the slug slime and the snail slime
The slug slime is thicker than the snail slime and when you come in contact with them it is always more difficult to get them off, unlike the snail slime. They are so thick because it helps protect them from being eaten by predators. it also helps them heal when bruised and prevents any form of infection. (Source)
Can a snail transform into a slug or vice-versa?
Naturally, this is not possible. Although they have so many similarities, it goes against human nature for any to transform into one another. Nevertheless, this has been tried scientifically by a team of biologists in 2010. (Source)
Do slugs eat dead snails?
Some Slugs are omnivorous such as the Arion slugs so are known to feed on other snails especially when dead as well as worms and organic materials. They feed on snails because it offers them a good source of protein.
some other slug species such as the Leopard slug (Limax maximus) are predatory and carnivorous, hunting and eating other slugs and snails dead or alive. These species are may also feed on the eggs of other slugs and snails (Source)
Other slug species like those located in the UK are herbivorous, feeding on flowers, mushrooms, decaying plant materials, leaves, lichens, and fruits.
Note that both Slugs and snails have both been observed to eat dead members of their own species. Refer to this article on Snail behavior and their nature to find out more about snails eating slugs.
Final thoughts
You can never mix up the two creatures – snails and slugs because they have a distinct difference which is the presence of a shell on the snails and the absence of it on slugs. Regardless of this difference, they originate from the same group of animals and are of the same structure, with very similar behavior.