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11 Types of Slugs (With Pictures & Facts)

Many species of slugs have evolved over millions of years in different parts of the world, and some even made their way to new places, like North America. Only 40 types of slugs are found in North America, so it’s only natural to be curious about these animals, as they typically go unnoticed by most people. Since they move slowly, these creatures without shells have unique ways of living, as they need to be careful because they’re easy to take advantage of. 

11 Types of slugs

Let’s take a look at some of the slugs that live on the continent and explore some of their traits in this article. 

1. Gray field slug

Gray field slug
Gray field slug | image by Paul Morris via Flickr | CC BY-SA 2.0

Scientific Name: Deroceras reticulatum 

The gray field slug is a type of mollusk native to the Atlantic Islands, Europe, and North Africa. However, it was brought to the Americas and can now be found in many parts of Michigan, particularly in the Northern and Southern regions.

They can be identified by their creamy or light coffee cream coloration, thick skin, and colorless mucous. Depending on the environment, they can grow to be anywhere from 40 to 60 millimeters in length, and in a single night, they can travel a distance of up to 40 feet. 

2. Pacific Banana Slug

Pacific banana slug
Pacific banana slug | image by gdahlman via Flickr | CC BY 2.0

Scientific Name: Ariolimax columbianus

The pacific banana slug, the world’s second-largest species of terrestrial slug, is among those you’ll most likely see along the Pacific coast of North America.

The length of this creature can reach up to 9.8 inches, and its coloration can range from bright yellow to greenish brown to tan to white. The tail of this banana slug is also covered in black spots, and their overall coloration is determined by both their health and the environment in which they live.  

3. Black field slug

Black field slug
Black field slug | image by MonkeySimon via Wikimedia Commons | CC BY 2.0

Scientific Name: Arion hortensis

Black field slugs are mollusks that you may also know by the name garden slug. The species displays a color ranging from gray to bluish-black, adorned with dark lateral bands, and it can grow to a length of 40 mm.

When they feel threatened, they produce a slimy yellow to dark yellow substance. The lifespan of these creatures can extend up to 12 months, during which they can lay from 158 to 205 eggs. 

4. Leopard slug (spotted garden slug)

Leopard slug
Leopard slug | image by Jim, the Photographer via Flickr | CC BY 2.0

Scientific Name: Limax maximus

The leopard slug, which can reach a length of up to 8 inches, is one of the largest-keeled slugs. As members of the family of keeled snails, they have a short keel on the end of their tails and have a coloration that’s either light grayish or gray-brown with darker blotches on their bodies.

In addition to feeding on decaying vegetation and fungi, these mollusks are known to consume other species of slugs, and you can find them living close to human habitations. 

5. Black arion

Black arion
Black arion | image by gailhampshire via Flickr | CC BY 2.0

Scientific Name: Arion ater

The black arion is a mollusk species known to cause problems in agricultural settings and is likely to be found in the United States. Since it avoids sunlight, it’s predominantly nocturnal and will only venture out to feed when there is cloud cover or at night.

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Although they mate with their own kind, they can also self-fertilize and will lay their eggs in a dark, moist environment. They also produce three types of mucous, two of which are used for locomotion and the third to ward off predators. 

6. Greenhouse slug

Greenhouse slug
Greenhouse slug | image by Justin Johnsen via Wikimedia Commons | CC BY-SA 4.0

Scientific Name: Milax gagates

The greenhouse slug is a type of terrestrial mollusk that was once only found in Morocco and Spain but is now widespread across the United States. These species can reach a length of up to 50 mm and have a coloration ranging from dark gray to black.

They prefer wet environments and can often be found hiding in crevices or beneath rocks near water. Since they’re a semelparous species, they only reproduce and lay eggs once in their entire lives. After doing so, they pass away 15 to 30 days later.

7. Tawny garden slug

Tawny garden slug
Tawny garden slug | image by Peter O’Connor aka anemoneprojectors via Flickr | CC BY-SA 2.0

Scientific Name: Limax flavus

Tawny garden slugs are also called yellow slugs due to their body with yellow coloration, gray mottling, and pale blue tentacles. Because they’re mollusks that live near human habitats, you can frequently find them in damp places like cellars, kitchens, and gardens, as well as under stones; however, because of their nocturnal behaviors, they’re typically unnoticed. 

8. Hedgehog slug

Hedgehog slug
Hedgehog slug | image by James K. Lindsey via Wikimedia Commons | CC BY-SA 2.5

Scientific Name: Arion intermedius

Hedgehog slugs earned their name because of the prickly points on their tubercles that give texture to their bodies. These organisms, which can reach a length of 0.7 inches, are found in forests and grasslands, where they eat fungi and plants.

In the past, it was believed that they could only reproduce through self-fertilization. However, researchers have observed that they also engage in cross-fertilization or exchange sperm with a mate. 

9. Brownbanded arion

Brownbanded arion
Brownbanded arion | image by James K. Lindsey via Wikimedia Commons | CC BY-SA 2.5

Scientific Name: Arion circumscriptus

You’re likely to come across the brownbanded arion, a land slug while exploring the beautiful broadleaved woods of temperate climates. These creatures live in various hiding spots, such as the litter layer, under dead wood, and beneath bark.

It’s also an introduced species in America, and you might find it in gardens. Research indicates that their dark graying color, which occasionally has a hint of blue or brown, may also be affected by what they eat. 

10. Red slug

Red slug
Red slug | image by Andreas Rockstein via Flickr | CC BY-SA 2.0

Scientific Name: Arion rufus

The red slug, also known as the chocolate arion, is a land mollusk that has a reddish coloration. Sometimes, the animal’s color can be orange, yellowish, brown, grayish, or black, and you may come across lateral bands on many smaller species.

You can spot these creatures living in various natural habitats, such as woodlands, meadows, the edges of water bodies, coastal areas, and even moorlands. Even though they’re typically nocturnal, these creatures may venture out during the day, especially when it’s raining.  

11. Tree slug

Tree slug
Tree slug | image by Paul Asman and Jill Lenoble via Flickr | CC BY 2.0

Scientific Name: Lehmannia marginata

The tree slug can be identified by its gray to reddish coloration, which features a distinctive lighter median stripe running down its back. Woodland areas are their habitat, where they actively seek out and consume hosta, vegetables, wheat, and jimson weed.

They also show a preference for a diet consisting mainly of vegetables. Tree slugs can live up to 26 months and lay a total of 105 to 132 eggs during their lifetime.