Glass-Snails

Glass snails, such as this whimsical piece by GlassBorisov, are a delightful way to add art and color to houseplants and your garden.

Glass snail by GlassBorisov

The same is generally not true of real snails. Yesterday morning, after our first rain of the year, I noticed a snail trail. Snail trails are pretty normal in most gardens, but this one ended with a flat-bodied snail I’d never seen before.

Glass snail in hand

Introducing, the glass-snail family (Oxychilidae). Glass-snails get their name because their shells are translucent. Looking closely at my discovery, I could see the snail body through the shell!

Glass-snails are land snails that breathe air. Unlike marine snails, which breath using a single gill, land snails have evolved a single, simple lung. Most glass-snails are omnivores. They eat everything: live plants, dead plants, dead animals, insects, poop, other slugs and snails (and their eggs), sowbugs, and earthworms.

Sorting out glass snails

Specific characteristics are used when comparing different snail species, including height, width, number of whorls, and the umbilicus. The umbilicus is the snail’s bellybutton. It is the tiny opening at the center of the whorls on the underside of the snail’s shell.

Only three glass snails are found in California, at this time: cellar snails, garlic snails, and Drapernaud’s snail. [I'm not sure if my guest is a cellar or Drapernaud's glass-snail, but I'll keep you posted.]

​Cellar glass-snails

Cellar glass-snails (Oxychilus cellarius) have shiny, translucent yellowish-brown shells are just under 1/2 an inch wide, 1/6 of an inch tall, with 5-1/2 to 6 whorls. The umbilicus is very narrow. The snail itself is bluish-gray, with small brown freckles and a groove that runs along each side of the foot

Garlic snail shells (H. Zell) CC BY 3.0

Garlic snail

The garlic glass-snail (Oxychilus alliarius) gets its Latin name, a twist on the onion family (Allium), because they emit a garlic odor when disturbed. Originally from the Netherlands, Great Britain, Ireland, Poland, and the Czech Republic, the garlic snail has spread its range to include Columbia, Latvia, and California. Garlic snails are reddish or greenish brown, and the snail is blackish blue. The shell is 1/4 of an inch in diameter, a little more than 1/8 of an inch high, with 4 or 4-1/2 slightly convex whorls. The umbilicus is 1/6 of the overall diameter, and the whorls are coiled more narrowly than cellar glass-snails.

Drapernaud’s glass-snail (Michal Maňas) CC BY 4.0

Drapernaud’s glass-snail

Drapernaud’s glass-snail (Oxychilus draparnaudi) is larger than the other glass snails, being slightly more than 1/2 an inch in diameter, and the shell is a waxy yellowish-brown on top and somewhat lighter underneath. The body is a dark blue and gray color. Drapernaud’s glass-snail is carnivorous.

How to control snails

Unless you are enjoying artistic versions of this common pest, managing snails is an ongoing task. It comes as no surprise that these snails’ peak breeding season in the Bay Area is autumn, just before our rainy season begins. 

The first step in snail management is to inspect and quarantine new plants. A single snail can lay over 400 eggs. Putting new plants into isolation for a couple of days, with a beer trap nearby, can prevent years of frustration. Once infestation occurs, try to reduce hiding places, such as boards, stones, and other debris. Regularly applying slug and snail bait, and using beer traps, can take a big bite out of the snail population, before they start taking bites out of your plants. Going outside with a flashlight at night, you can catch them feeding - handpick them and feed them to your chickens or dispose of them in the trash.

Did you know that snails have a powerful sense of smell?

Now you know.