Story and photographs By Joan Herrmann
Whereiwander… several years ago a book by Elizabeth Tova Bailey entitled “The SOUND of a WILD SNAIL EATING” intrigued me enough to go wandering around our woods in search of these amazing creatures. I also used many of my field guides to help me in my quest and found that their habitats can also be marshes and gardens, both floral and vegetable, in addition to woodlands. Most of their day is spent under leaves, mulch, rocks, and logs when not eating or looking for a mate. Their life span as an adult is between two or three years, however, in captivity, they have been known to live ten or even fifteen years.
Terrestrial (land) snails can be found in all parts of New York State. Many of them are not native species but have arrived as eggs attached to plants, to boats, or via the aquarium businesses. Once they have arrived just like the nonnative wildflower seeds or insects they have come without “Nature’s Balance”. There are diseases and predators that keep all flora and fauna from becoming invasive and these snails arrive without these deterrents. Not everyone, especially gardeners, are pleased to find them and continually pursue ways to exterminate them. I have found numerous books that offer interesting facts and data about snails. In New York State it is possible to find one hundred species and at least twenty-eight species may be found in the Adirondacks. Native snails eat fungi (mushrooms) and decaying vegetations. Their predators include numerous mammals, birds, reptiles, amphibians, and insects.
Terrestrial snails carry their home with them and move by gliding on their muscular foot. Gastropoda is the Class for snails and slugs. More than forty-three thousand species of snails live in the oceans, freshwater, or on land, and are second only to insects as the most numerous species on this planet. The snail’s shell protects it from the weather and keeps in moisture, but it also reduces its mobility. The shells’ appearance can vary from species to species, in shape, size, and texture (smooth or bumpy, thick or thin). The camouflaging color of the shell allows them to remain hidden from predators. The shell contains three layers; the inner and middle are made of calcium carbonate and the outer is mostly proteins that maintain the shells’ color. The shell begins when the snail is an embryo and keeps growing layer by layer as cells on the lip of the opening (aperture) release a calcium carbonate substance as a liquid and eventually harden. The shell undergoes a unique process called torsion that creates a spiral shape. The shell can spiral either to the right (clockwise) or to the left (counterclockwise), but to the right is the most common. If the shell spirals to the right it is known as dextral and spirals to the left are known as sinistral. A gland in the mantle (the covering over the body’s visceral mass) secretes the calcium carbonate.
A snail’s body is divided into three parts, head, foot, and the visceral mass. The visceral mass contains the digestive, excretory and reproductive organs. The mantel covering the visceral mass is a skin-like organ living inside of the shell. Snails have a simple brain with the ability of associated learning and long-term memory. Snails have a liver, heart, stomach, kidney, mouth, eyes, male and female reproductive organs, one lung, mucous gland, salivary gland, and a crop. Its mouth contains an amazing tongue-like organ called a radula. The radula is used for scraping or cutting food. It contains minute rows of tiny teeth that are sharp and point inward. Each row contains about thirty-three teeth and there are about eighty rows of them that function like a tool called a rasp. A rasp is a coarse metal tool used to file metal, wood, or other hard materials. When the front row of the radula becomes worn it can be replaced by a fresh new row from the back; similar to our nails breaking and re-growing.
Snails produce mucus, enormous amounts of mucus. The mucus is used for locomotion and it also insulates and keeps dirt and germs away. Water snails have a hardened lid on the aperture of the shell, but land snails do not, instead, land snails secrete mucus to seal the aperture. As snails move they leave a shiny trail as they travel on their secreted mucus. They will create an epiphragm or plug of mucus at their aperture and stick themselves to a rock or tree branch. Terrestrial snails have two sets of tentacles. A tentacle is an elongated flexible non-segmented extension that can grasp and stretch, different from antennae that are sensory appendages on insects, crustaceans, or myriapods (centipedes and millipedes). The upper tentacles on the snail are long and contain the eyes and smelling sensors. The eyes appear as shiny black dots and can recognize light or dark. The tentacles can move up or down and to the left and right. The lower tentacles are shorter and contain chemoreceptors and can taste and smell. Both pairs may quickly withdraw at the hint of danger. Muscles are used to withdraw the tentacles and they use their blood pressure to extend them.
Having only one lung is not a problem for snails, the mantle expands and compresses air in and carbon dioxide exits through a special opening called the pneumostome on the right side of its body. The pneumostome opens and closes at will. When inhaling it is kept closed to preserve body moisture. Snails are extremely strong for their size and experiments have been done in which they can carry as much as fifty percent of their own body weight.
Courtship is in early summer for the adult land snails. They are a hermaphrodite which means that their body contains both male and female reproductive organs. However, they still need a mate to reproduce and their courtship is a special ritual. Snails lay their eggs either singly or in clusters in leaf litter or under logs. They may lay as many as one hundred eggs that hatch In two to four weeks.
Snails are truly interesting and you can find many books about them at our local stores or online. I hope that this column has given you an opportunity to see just how intriguing they really are…
As a Professional Nature Photographer, Naturalist, and Outdoor Educator, Joan Herrmann has been teaching and doing programs for Schools, Garden Clubs, Libraries, and Nature Centers, about 38 years. After moving from the Rochester area in 1995 she began her Photography business, Essence of Nature, and also became a co-owner of The Artworks in Old Forge, New York. As a docent at Munson, Williams, Proctor Arts Institute, in Utica, New York she has been educating children and adults, for nineteen years.
In 2007 she began working with the Black River Outdoor Educational Program (BROEP) and in 2013 and 2014 did a week-long summer program at BROEP in conjunction with Mohawk Valley Community College (MVCC). Using her love of both nature and photography she created a Flora/Fauna outdoor educational program teaching students (ages 6 to 14) the joys of nature and creative photography skills.
Joan’s love of nature has been a lifelong study of Birds, Wildflowers, Mosses, Ferns, Trees, Amphibians, Reptiles, Grasses, Insects, Spiders, Tracks, Scat, and Galls. She has assisted in the cataloging of all trails used by the hiking Coaches and photographed and identified seasonal Flora.
Since October 2016 she has been writing a bimonthly nature column with Adirondack Express Newspaper. In October of 2019, she began a bi-monthly column with My Little Falls Newspaper. You may reach her at email@example.com