08 September 2010

Cunningham slugs

A couple of weeks ago we visited Cunningham Falls State Park near Frederick, Maryland. When during a hike I stopped to look at a trail sign, I noticed some peculiar marks on the back of the sign on the other side of the post.


It didn't take too long to recognize them as the feeding tracks of slugs. Here is a close-up.


The brownish layer covering the back of the sign is apparently some sort of algae (cyanobacteria), which slugs like to eat. You can see the marks left by the individual teeth of the radulae of at least 2 slugs, one large and one small.

This post was also about slug feeding tracks.

8 comments:

mountainbeltway said...

Very cool.

Anonymous said...

Can I ask what may be a silly question: how do you know they are from slugs and not from snails?

Susan J. Hewitt

AYDIN ÖRSTAN said...

Susan: Somebody else has asked the same question in an e-mail. I am assuming they are slug tracks, because around here there are more climbing slugs than there are climbing snails. I have also witnessed slugs (but not snails) in the act of creating similar tracks. But yes, snails could also create similar looking feeding tracks.

vanessa cardui said...

How do you think the slugs "know" the algae is up there on the back of a trail sign?

AYDIN ÖRSTAN said...

They normally climb up trees or walls of houses in search of food. In this case, it is possible that the algae growth extended all the way down to the bottom of the pole carrying the sign.

Tina Pham said...

where are the teeth marks?

AYDIN ÖRSTAN said...

Those are the teeth marks.

Tina Pham said...

Oh, I thought those were the tracks the slugs made.