Pacific sideband snails (Monadenia fidelis) are endemic to the Pacific Coast of North America from Alaska to California. They reside in cool, moist, shaded forests feeding on fungi and plant material. Pacific sidebands climb trees and can be found up to 20 feet or more above the ground.
This mollusk has a chestnut to dark rose shell with a dark band around the perimeter of the shell. There are about 7 whorls with a thin black line at the bottom of each whorl. The Pacific sideband’s body is rosy pink to pinkish brown and wrinkly. The eyes are on two retractable tentacles on the forehead while the nostrils occur on two shorter tentacles on either side of the mouth. The mantle cavity of a Pacific sideband has evolved into a lung and it breathes through a single opening on the right side of the body. This is unique, as other snails have gills.
Pacific sidebands are hermaphrodites, each snail has both male and female reproductive organs. Two snails shoot “love darts” at each other in an elaborate courtship process. This is not copulation, but rather “playing cupid” before mating. The exact function of the “love darts” is not known but they are thought to enhance reproductive success after mating. Eggs are deposited in leaf litter in the spring.
Pacific sidebands hibernate in the winter. During dry summer months they can enter partial hibernation.
This Pacific sideband was photographed along Trillium Falls Trail near Prairie Creek State Park in California.