by Kim Doner
I recently read that the spiral is nature’s most efficient shape, at which point I naturally started seeing spirals everywhere — van Gogh’s Starry Night, winding staircases, chameleons’ tails, and the shells that house mollusks, better known as snails.
It makes sense. If you’ve ever thrown a pot or woven a basket, think how growth from the middle out is the simplest path to take. Yet snails are hardly simple, and the ways they vary from humans are profound.
Most of us recognize snails — a round shell with whorls starting from the center and gradually expanding to a lip, or mantle. The mantle attaches to a slimy creature made of a single foot beneath a bizarre sort of face. Land snails have two sets of facial tentacles. The top set comprises eyes of a sort because they don’t see color, and their vision is uncoordinated out there at the tips of those stalks. The lower set of tentacles is a nose because snails can also smell — but it has no ears anywhere.
Snails are deaf.
The mouth of a snail houses as many as 20,000 teeth, depending on the species (and there are thousands of species because these guys are found throughout land and sea). The teeth help to scrape calcium deposits from anything available to supplement a mostly vegetarian diet. But when times are tough, they will slowly gnaw another snail’s shell down to nothing.
Snails as Pets
People interested in pet snails can often capture a few from their yards, which is legal because America’s garden snails are invasive species. If you’re intrigued with the idea of a vivarium, do be aware that snails are hermaphroditic and can even impregnate themselves, although homemade offspring are usually inferior and seldom survive. In the wild, younger snails will gravitate to older ones to mate, which ensures a stronger gene pool.
Bizarre fact: Land snails use “love darts” to fire into each other’s bodies, daggers coated with a special mucus that triggers mating (and these knives would be about 15 inches long if sized for humans — ack). But the snail partners don’t seem to mind; it’s all part of the dance.
And they never stop breeding. Many species can lay eggs monthly, which is handy if you’re a snail-eating animal but not so great if you’re housing them all, even if they are generally low maintenance.
But are snails any fun? Good question.
These guys are nocturnal to crepuscular. (Isn’t that a great word? It means “active during dawn and dusk.”) So their social lives are limited, and they are big sleepers, about 14 hours or more per day. Snails have rudimentary brains, and it has been proved that they can learn through association and can feel pain but generally aren’t known to recognize owners or respond to cuddling.
If you decide to pet a snail, first be sure your hands are washed, rinsed, and damp; lotions, soaps, salts, and other deposits might burn their skin. Once you’re done, place the snail back and again wash your hands; you don’t want their bacteria and parasites introduced to your system. Snail cooties (my term, not National Geographic’s) account for about 200,000 global deaths per year.
Killers and Giants
And speaking of death, killer snails exist. The textile cone snail can be found off Florida coasts. It is carnivorous. It has hollow, harpoonlike teeth that inject a venom as they jab prey. Bad news for humans: Stepping on one can kill you with their neurotoxin, for which there is no antivenin.
(Agatha Christie missed the boat here; writing a crime story about a sloooooooow death by snail would be something unique in the murder-mystery world. And don’t forget those love darts either.)
Speaking of Florida, the state has been besieged over the years by a not-so-minuscule kind of snail that is illegal to own in the United States but has been released by irresponsible pet owners. That is the giant African snail, and “giant” is appropriate for a snail that can weigh close to a pound, with lengths as great as 11 inches and widths of five inches.
Looking much like humongous live boogers beneath their shells, giant snails are highly destructive and perfectly happy to munch (and reproduce) their way through Floridian farms. Florida has fought back and won (twice) by using Labrador retrievers to sniff out these enemies and bring them to justice, so to speak, although I do wonder why the pythons aren’t stepping up for population control there. Could be a win-win situation if said python could be trapped with a gut full of escargot, right?
Another intriguing trait of the giant African snail is the ability to evoke a kind of hibernation. Glands in the mantle secrete a calcareous compound, which dries on contact with air. They literally seal themselves into their shells and wait out droughts for as long as three years, which sounds crazy-making to me, but again, they’re not exactly the brightest bulbs on the Christmas tree either.
Expanding Outward
The mantle is crucial to snails; it is also the tissue that grows the shell. Unlike a tree, whose youngest part is the center of its rings, the shell’s center is the oldest part of the snail, spiraling centrally outward into the newest addition. Most snail shells have a dextral, or right-directional, curl, but there are exceptions. Shells that go left, or counterclockwise, are called sinistral. (More fun facts — dextral and sinistral became English terms pertaining to sword fighting with the right or left hand.)
As shells expand, nature again shows genius. The Fibonacci sequence, represented by the golden ratio, applies to the ever-widening curves, from the tiniest of these gastropods to a vast number of other plants and animals that follow that pattern. Study this the next time you find a snail; maybe even research how they breathe, reproduce, and poop. Trust me, there’s more on these critters than you might guess. It might leave your head spinning or thoughts spiraling….
Or both.
