Surprising Facts About Snails that Are Anything But Harmless

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When you think of snails, what comes to mind? Maybe, you picture Gary, the stalk-eyed snail from the popular SpongeBob cartoon series? Gary meows like a cat and seems so harmless and strangely cute.

However, Gary’s life gets surprising if you trace back his family tree. There, you’ll see that Gary and Patrick the Starfish are cousins. Oh, and Gary is royalty and is known for having all kinds of surprising things under his shell.

When it comes to real-life snails, they can be extremely surprising as well. So, although they may generally be slow, slimy veggie munchers, snails can sometimes defy belief. 

Glorious Gastropods

Recently, we shared a story about a related gastropod, a sea slug called the Leaf Sheep. It’s one of the cutest creatures you’ll ever see, resembling a cartoon sheep with tiny beady eyes. What makes it even more outstanding is its amazing ability to survive on power from the sun. That’s right; they are solar-powered slugs related to snails.

Notably, both slugs and snails are gastropods, a class of animals named for gastros (stomach) and podos (foot). It makes sense as you watch them sliding along on a large muscular foot, filling their mouths with food and making mucus. 

Grouped with other invertebrates, they are mollusks, including nudibranchs, slugs, snails, and even intelligent octopuses. However, gastropods are the largest class of the phylum called mollusks, with more than 80,000 species. 

Recommended: Octopus Facts – Surprising Facts about Octopus

While most gastropods live in water, many reside on land, where they tend to drive your gardening friends crazy munching on flowers. Snails often crawl along the ground, but there are tree-dwelling snails too.

Of course, the main difference between snails and slugs is the shell. Of course, if you’ve ever been to the beach, you know the shells can be spectacular, colorful, and endlessly varied.

See ten beautiful snail shells below from ZoneA:

Assassin Snails

While most snails pose more threat to decaying vegetation, some are murderous assassins. One of these carnivorous snails you may encounter yourself is the Assassin Snail (Anentome helena). 

The freshwater snails come from tropical South-East Asia but are turning up in aquariums in the US. Its original home is in Thailand, Cambodia, Indonesia, Laos, and Malaysia.

Since the snails are predators of other snails, they are sold for the aquarium trade. Most reach no more than about an inch long. 

Unfortunately, this means hobbyists could release them to the wild, which poses a significant threat to native snails. As with all pets, it’s never a good idea to release them into the environment.

Assassin snail, Anentome helena
Assassin snail, Anentome helena by Werner73 via Wikimedia Commons, (CC BY 3.0)

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Snails with Chainsaws

Often, common aquatic snails can spread quickly and are hard to eliminate. So, aquarists purchase these yellowish spiral snails with brown stripes. Although not particularly pretty, they survive by hunting and killing invertebrates. However, they won’t damage aquarium plants like other snails. On the other hand, they also won’t eat algae, a reason people generally try snails in their aquariums.

When the Assassin Snail finds another snail, it extends a long trunk-like proboscis. At the tip, scraping teeth called denticles make up the radula. Moving like a tiny chainsaw, the Assassin tears apart its prey. Unfortunately for the victim, there is no paralyzing venom, so it is slowly eaten alive. 

Certainly, these snails are tiny but gruesome killers. Generally, they don’t attack each other; they will come together to feed on prey.

See a video about the Assassin Snail below (with a warning of graphic snail violence!):

Murderous Cone Snails

Assassin Snails may not be your average snail, but they are amateur killers compared to Cone Snails. Concealed in beautifully ornate shells that any collector would covet, a harmless appearing snail harbors potent venom and a harpoon.

Of the 1,000 species, each Cone Snail has its own venom recipe, according to the Atlantic. Thus, the snails are expert chemists.

Conidae, cone snails
Cone Snails: Conidae by Pet via Wikimedia Commons (CC BY-SA 3.0)

Devious Strategizing Snails

By intoxicating, paralyzing, and tricking their victims, the slow snails can gorge themselves on their still-alive bodies.

Several ingredients seem to closely resemble chemicals naturally made in fish, worms, and other mollusks; in manufacturing them, cone snails can turn their prey’s bodies against themselves. This sort of predatory mimicry is a devious strategy for an otherwise lethargic hunter: If you can’t beat them with speed, narc them and murder them. Had Agatha Christie been a mollusk, she might have been proud,” wrote Katherine J. Wu.

See more about Cone Snails from Deep Look:

When Snails Attack

Whereas the Assassin Snail has a slow-moving attack, some Cone Snails can harpoon fish with lightning-fast speed. Then, it injects specialized toxins as if through a hypodermic needle. For example, the first toxin stuns the prey, followed by another toxin to induce paralysis. 

Other snails use a recipe that simulates their favorite victim’s pheromones, tricking them into thinking they are about to mate. Sadly, it’s all snail sabotage, and a tragic end awaits.

Since their food is often large, these mollusk’s mouths can expand, ballooning out to gorge on the victims.

Even more surprising, some Cone Snails actively hunt schools of fish. After sneaking up, they release a cloud of chemicals containing insulin, causing the fish to have low blood sugar. Then, the lethargic, hypnotized fish are ideal prey for the snail, which uses its mouth “like a net.”

Different species have different sophisticated tactics and can either tether themselves to their prey or inject them and lay in wait. In some cases, the snails have killed humans with their potent venom. 

A species called the Geography Cone (Conus geographus) is the most dangerous species to humans. It’s found in the Indo-Pacific, and collectors prize its beautiful shell. If stung, there is no antivenin, and the venom can paralyze the diaphragm, stopping breathing.

Conus geographus
Conus geographus by Almed2 via Wikimedia Commons, (CC BY-SA 3.0)

Fortunately, scientists studying Cone Snail venom find great potential. According to National Geographic, proteins in the venom could prove 10,000 times more potent than morphine. Since the 50s, research has led to over 300 patents related to Cone Snail toxins.

See more from Alan Kohn, professor emeritus of biology at the University of Washington, who pioneered research into cone snails as a Yale graduate student in the 1950s. From Hakai Magazine:


Featured image: Conidae by Pet via Wikimedia Commons (CC BY-SA 3.0) with screenshot via YouTube