Ecology

Snail teeth and other nature oddities

Anne Gageby
Strawberry Hill Nature Preserve

(8/2024) I recently saw a meme with an image of a snail superimposed with fake teeth. The picture was meant to be funny and clownish. A moment of silliness as I doomscrolled the internet. As I studied the grinning snail a question popped into my mind: do snails have teeth?

It turns out they do though their teeth are quite different from ours. Snails’ mouths contain a radula, a membrane similar to a tongue. The radula is covered in thousands of tiny teeth and used to scrape away at their food. Snail teeth are extremely durable though they do get worn down by eating. Like sharks, snails replace their teeth regularly. This was an interesting discovery considering snails’ diets consist of plant matter and fungi. Not exactly the type of meal that wears down teeth. It turns out my understanding of snails was incorrect.

Most land snails are generalist feeders, meaning they eat a wide variety of organic and inorganic material beyond fungi and green and decaying plants. They consume animal carcasses and scat, rotting wood, empty snail shells, and even certain rocks such as limestone. Snails and their shell-less relatives, slugs, are technically classified as decomposers though their role is significantly smaller than other decomposers like worms and fungi.

Some snail species will even feed on others of their kind. The assassin snail is well-known for feeding on smaller snails no matter their species. Though they generally avoid single-handedly attacking larger snails, the assassin snail has been known to gang up on larger snails and make a meal out of them. The notion of a snail’s existence as gentle is just a mirage. It’s a snail-eat-snail world after all, and those teeth are designed for destruction.

Mother Nature is full of wonderful contradictions and oddities that keep nature enthusiasts on their toes. A personal favorite of mine is jewelweed. This lovely plant grows all over Strawberry Hill’s campus and is a destination for hummingbirds as well as pollinating insects such as bees and butterflies. Its beautiful orange flowers provide a delightful pop of color against a sea of green in summer and fall. But the most fascinating aspect of this plant is its hydrophobic leaves. Water droplets bead on top of the leaves and sparkle with a jewel-like appearance. While this is quite fascinating and beautiful to witness, it’s contradictory because jewelweed occurs in moist areas such as floodplain forests, marshes, and bogs. In other words, it only grows in wetlands. A water-based plant with hydrophobic leaves is a conundrum, for sure.

Another fun puzzle is the hydrophobic nature of water skippers. These aquatic insects are known for their ability to "walk" on water and the dimples their feet make on the water’s surface. Water skippers are found in creeks, ponds, rivers, and marshes and yet have hydrophobic bodies that make them uniquely adapted to their watery habitat.

Scientists have been studying the reason behind water skippers’ buoyancy to better understand and hopefully replicate this phenomenon. By using the latest technology, they’ve discovered that water skippers have microscopic hairs covering their bodies. These hairs repel water and capture air creating a perfect adaptation for flotation and quick movement across the water’s surface. This adaptation takes advantage of a very basic scientific concept: the surface tension of water. You see, water behaves differently on the surface. Water molecules are highly attracted to each other, and they stick together. This cohesion creates a dense molecular membrane at the surface level. Water skippers walk on this membrane, avoiding breaking the surface tension of the water. It’s a pretty cool adaptation that allows water skippers to exist in aquatic environments while not actually living in the water.

Another oddity that boggles the mind is the dragonfly. They’re dainty and lovely summer insects that shimmer with an ethereal iridescence. They’re also the most efficient and effective hunters in the world. Dragonflies have an estimated 95% success rate and can consume hundreds of insects per day, including mosquitoes and other biting insects. In a world of apex predators with powerful claws and terrifying teeth such as wolves, lions, and tigers, dragonflies are, by comparison, tiny and seemingly delicate. The smallest dragonfly’s wingspan is less than an inch and even the largest only spans about six inches. Size is a deceptive ruler by which to measure a hunter’s ability, however. Dragonflies are beautiful and deadly.

There are more than 5,000 species of dragonflies and related damselflies worldwide. Both belong to the order Odonata, meaning "the toothed one." Dragonflies and damselflies have powerful serrated mandibles that can crush prey. And yet that’s not their most impressive adaptation. Dragonfly wing muscles are attached to a hinge at the base of each wing. Most insects’ four wings are coupled and can only move as part of their pair, but dragonflies’ four wings can move independently. This gives dragonflies the ability to fly in all directions – even backward. This adaptation allows them to change their speed and direction faster than most insects. Many dragonfly species even make their kills mid-flight.

Dragonflies’ flight isn’t the only key to their hunting success rate, however. Recent studies have discovered dragonflies’ brains have the ability to predict their prey’s movements by anticipating the prey’s trajectory. Think of a human watching a ball thrown in the air. We’re able to track the ball’s location and anticipate where it will land by using a complex system of visual calculations. Until recently, it was believed this ability only existed in mammals. It turns out that dragonflies can do something similar. No wonder they’re able to snatch a meal mid-flight. All of these adaptations have made dragonflies the world’s deadliest hunter. Fortunately for humans, they’re a fraction of our size and prefer mosquitoes to people.

Nature is full of incredible contradictions and puzzling truths. I love hearing about new discoveries that put a question mark on my previous notions and fill in the gaps in my knowledge. The world outside is truly fascinating and ever-changing. It makes me wonder what oddities we have yet to discover.

Anne Gageby is the Environmental Education Manager of the Strawberry Hill Foundation. Strawberry Hill inspires stewardship of our natural world by
connecting the community with educational opportunities.
 Learn more by visiting StrawberryHill.org.