The Poweshiek Skipper Project

Terrestrial Snails


Anguispira alternata (Say, 1816)

Flamed Tigersnail

This snail has also been known as Helix alternata and Patula alternata.

This is a large, easily recognized snail.  It does not have a reflected lip, the aperature has no denticles, and it has an open umbilicus.  It has fairly heavy sculpted ribs in a spiral around the shell.  Younger individuals have distinctive red markings that alternate around the spiral  of the shell.

This snail is widely distributed in the northeastern part of the United States, and seems to have been found in most of the counties of Iowa where there are records.  I have seen it a number of places.  It is one of the most common of the large snails.  It will be found in most good woodlands.


It has been noted that this snail has a reddish color slime.  I have not noticed that so much when the animal is doing its normal crawling.  However, if it is handled it will release a reddish froth.  This seems to be some kind of defensive response but there does not seem to be any noticeable odor that goes along with it.
One hot May afternoon I went to Berry Woods, which is a woodland preserve owned by The Nature Conservancy near Indianola, Iowa.  There was a sudden thunderstorm which stopped shortly before I got there.  I had intended to photograph snails, so I looked under some logs and in the leaf litter.  The snails were harder to find than I had imagined they would be.  That is sort of the thing with snails--sometimes they are easy to find and sometimes they can't be located.

It started to rain again and I headed toward the car, thinking I was skunked.  Then I noticed a number of snails on certain trees.  They were typically from four to six feet above the ground.  They may have been feeding or it may have been some kind of pre-mating activity.  I did remove a couple for photographing elsewhere, and attempted to get some photos on the trees as well. 

I did not stay long because of the rain.  I have not witnessed anything like it since then.  I would like to know what was going on.