Nautre Notes

by Bob Thomas

If one encounters a pinkish spiraled (fusiform) two inch long snail in coastal Louisiana, it is probably a rosy wolfsnail, Euglandina rosea, a native of the southeastern U.S. They prefer woodlands, but are quite common in urban settings. Normally terrestrial, they may climb trees or enter water while feeding.

Rosy wolfsnails are feeding specialists on other mollusks. They will simply swallow small (up to 3 mm) snails and slugs. Their bodies are translucent enough that one can actually see the prey moving down the esophagus.

For larger snails, the wolfsnail first bites the exposed body, causing the prey to pull back into its shell. The wolfsnail then goes headfirst into the prey’s shell and finishes the meal. An adaptation that allows the rather large wolfsnail to reach deeply into the coils of its prey’s shell is its ability to evert the mouth into a prolonged proboscis.

Wolfsnails have been intentionally introduced many places to control exotic pest snails. As in most such introductions, the best laid plans have not always played out, with the demise of native snail populations often the result. Hawaii had 750 species of native land snails, and today more than half are extinct. Scientists think this is largely due to predation by rosy wolfsnails.

Rosy wolfsnails are hermaphroditic, having reproductive organs for both sexes. When they mate, they inseminate one another. They typically lay twenty or so eggs in moist soil.

As in all other related land snails, wolfsnails have two pairs of tentacles on the head. The long, upper pair has light sensitive eyespots on their tips. The short, lower pair functions in the sense of smell and touch. Wolfsnails have something extra – the lateral edges of their upper lip are extended to form an extra set of tentacles that resemble a moustache. From personal observations of feeding behavior, the tips of the moustache appear to function in following slime trails, and fold against the face during actual feeding.

Rosy wolfsnails are usually nocturnal, and are most active on warm, humid evenings. A nice rain seems to stimulate their appetites as well, and they are commonly found active on overcast days and at dawn or dusk.

Also published in Delta Journal, The Times Picayune, July 13, 2008.

Rosy wolfsnail, Euglandina rosea, crawling                               A mating pair of rosy wolfsnails. Being
off a sidewalk. Note the two pairs of tentacles                          hermaphroditic, they inseminate
and the lateral lip extensions.                                                 one another duirng mating.
Photo by Bob Thomas.                                                         Photo by Bob Thomas.

Rosy wolfsnail laying eggs.
Photo by David Castellanous.