08 April 2009

Small snails have small feces

VertigoFeces

This is an adult Vertigo pygmaea from the backyard. Their shells grow to be about 1.8 mm long. These snails have appeared in several previous posts (for example, here and here). I always find them on rocks. I had been suspecting that they grazed on the thin films of green algae that grow on those rocks.

I collected about a dozen of them last week. After I measured their shells, I put the little snails on a little piece of tree bark inside a little cup and then sprayed a little bit of water on them. The bark was covered with green algae. I have noticed over the years that the captive individuals of this species don't remain active for very long even when their surroundings remain wet. Sure enough, about a day later, all the snails in the cup had become dormant by attaching themselves to the bark or to the piece of toilet paper underneath, which was still damp.

That little stringy thing next to the snail is a clump of snail feces. Its dark green color indicates that the snail had fed on the algae on the bark. There were several other similar clumps. Now I know that at least the captive Vertigo pygmaea eats algae.

2 comments:

Theanne and Baron said...

Dear Sir, I live in west central Florida and have found some tiny white shells on the ground at the back of the apartment complex where I live. I've been trying to identify them and currently have pictures of them on my blog. If you have time would you please visit my blog to see if you can identify the snails? Thank you so much, Theanne of "Theanne and Baron"

Theanne and Baron said...

Dear Mr. Orstan, I very much appreciate you visiting my site and identifying the snail shells I had found. Mysteries are interesting but knowing the facts enables learning to occur. I never knew how many different tiny snails there are till I started this quest to identify the ones I found. Thank you very much, Theanne L Crossett