11:01 p.m. - 2005-03-20
Slugs and Snails! *New Picture 3/4/06*
Happy Spring! This weekend R reminded me of an animal sighting we shared this summer. We were running before a beer-sponsored 5k (part of our 10 Mile training). It was a lovely morning in downtown Minneapolis, and we followed the historic route near the Stone Arch bridge down to the base of the Washington Avenue bridge. We noticed glistening silver trails on the sidewalk, and it wasn't long before we found one of the creators of those trails: a dried out slug trapped in the sunshine!
I've always liked slugs and snails. Back in WI, the snails I encountered most often were those in the lakes, which we will not discuss in the Critter Corner article. It wasn't until I was in college when I discovered a land snail for the first time, under a rock in a park. Very exciting!
Terrestrial slugs and snails are members of the Gastropod family. In Greek, Gastropod breaks down to "stomach foot". Yum. There are three groups within this family: octopus and squid, clams and oysters, and snails and slugs, which are the only group that has land-dwelling species.
In MN, land snails have not been studied exhaustively. It is suspected that there are around 60 species here. In the US altogether there are 40 species of slugs.
Has anyone been out west and seen the giant Banana Slug?! Let me know!
The slugs I've seen here are small; less than one inch long. But Banana Slugs range from eight to eighteen inches!
If slugs don't have shells, why are slugs and snails classified in the same family? Ah ha! But they do! Slugs carry small flat shells under the skin on their back!
I recommend observing slugs up close. (If you don't mind a little slime!) Anyway, you'll see they have two sets of antennae; the larger optical tentacles and beneath, smaller bumps that are sensory tentacles. The mouth is under the head, on the "foot". You'll notice the front of the slug has a thicker layer, called a mantle. Underneath the mantle lies the anus and sexual organs. If you look carefully a hole might appear in the side of the mantle. This is called a pneumostome, which is the breathing hole. The slug can close this at will.
Slime or mucous is an important part of the slug/snail lifestyle. (As it is for the singer?!) Anyway, slime acts not only as the surface on which the slug travels, but also protects them from sharp objects. The most important purpose of the slime is to keep the animal moist. (Which is why salt kills slugs.)
Here is an XXX photo of two snails in action, courtesy of my friend AH!
In the "ew, gross" category: some slugs and snails are hermaphrodites! Including the ones in my fishtank? (That's hot.)
Slugs lay clusters of about a dozen eggs just under the surface of the soil. The eggs can stay there in a dormant state until conditions get wet enough - even if it takes years! Adult slugs hibernate under the soil too.
Gardeners will tell you what slugs like to eat! Strawberries are a favorite, along with lettuce and other vegetables. I assume MN snails eat the same, but I think they are less commonly found in gardens than slugs.
On the other end, slugs make good food for birds, fish, small mammals, and are the favorite meal for garter snakes!
The next time you're out on a moonlight summer night, keep your eye open for the glistening pathways of our Gastropod friend, the slug!
Slime-ly,
Wendell!
