What are Slugs?
The simplest description is that slugs are snails without shells. Some of these mollusks do, in fact, have a shell, but those that do have internalized the shell and use it to store minerals. Like snails, slugs secrete a film of mucus to protect their delicate skin and to “grease” the surface on which they are traveling.
Slugs are considered a major agricultural pest, and, according to some sources, a single acre of farmland can support nearly a quarter of a million slugs! That means even a small garden is likely to house thousands of them.
What Do Slugs Look Like?
Slugs look like an exceptionally fat worm with two snail-like eyestalks. Naturally, the eyestalks allow for vision, but they also contain olfactory organs as well. Slugs also have two small tentacles under their eyestalks that are used as feelers and taste buds.
Hidden under a slug’s tentacles is the mouth, which opens to release a radula. The radula is a tongue-like organ that has teeth-like protrusions that help it saw through food before ingestion.
In North America, slugs can measure up to 10 inches long.
Most slugs are light brown or gray in color, although the famed banana slug of the Pacific Northwest is often a bright yellow. The skin of a slug is exceptionally moist, and often covered in a thin layer of slimy mucus that helps it retain moisture and protects it from most predators, which dislike the taste.
What Attracts Slugs?
Two key things attract slugs: food and moisture. Unfortunately for gardeners, just about every plant – vegetables and flowers in particular – can serve as food for slugs. They are definitely not picky eaters!
Any area that stays moist during the day or during lengthy hot spells will be attractive to slugs. In particular, they are drawn to the moisture-retaining qualities of mulch, sod, leaves and straw.
Another interesting attractant to slugs are spaces where they can lay their eggs. Gardeners have found that slugs will often lay eggs in areas that have been raked or hoed, while they will avoid soil that has been left smooth by a garden tool. Why? The creases and bumps left by such tools create an ideal incubation area for slugs.
Are Slugs Harmful to Plants?
Yes, slugs can be very destructive garden, farm and landscaping pests. The sheer numbers of slugs in many areas – particularly in irrigated and overly wet locations – can result in massive plant destruction. A slug, which eats many times its body weight each night, simply destroys too much of the plant for it to recover.
Are Slugs Harmful to People or Pets?
We wouldn’t recommend eating a slug – either for you or your pets. First off, the mucus produced by slugs can cause excess drool or induce vomiting. Even worse, in times of stress, slugs are known to produce extra mucus as a deterrent, so your cat or dog would be eating a lot of slug slime.
Further, some slugs are infested with parasitical lungworm, so this parasite can infect your pet. If your pet seems to enjoy eating slugs, ask your veterinarian to provide it with a lungworm vaccine.
Another interesting fact is that slug slime has anesthetic properties – exposure to it will cause numbness. This is another reason why slugs have so few predators – anything that tries to eat a slug will have a numb mouth.
What do Slugs Eat?
Slugs will eat just about anything. A slug menu can include:
- Cardboard and paper
- Dead animals
- Decomposing plants
- Discarded human food and trash
- Pet food
- Seedlings and young plants
The Slug Life Cycle
Slugs are hermaphrodites, meaning they have both male and female reproductive organs. When two slugs meet, they can mate with one another and fertilize each other’s eggs.
A few days later, both will deposit eggs in a sheltered spot with adequate moisture. From there, the next generation of slugs is born.
Slugs, depending on their species, can live from 1 to 5 years. During the winter, slugs burrow underground to escape freezing temperatures. In fact, it’s said that nearly 95% of the slugs in an area are hidden underground.