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Home > Research Collections > News > Snails Love L.A.

Snails Love L.A.

Why so many snails (and slugs!) visit Southern California and never leave


They’re small, they’re slimy, and they might be hiding under your trash can right now. They’re snails! (And slugs!) Often overlooked, these little animals are part of urban nature — the living things that live alongside humans in the concrete jungles of our cities.

Malacology Assistant Curator Jann Vendetti and dozens of active citizen scientists are in the midst of a collaborative Southern California snail (and slug!) census — the first ever — because, believe it or not, we actually don’t know much about which snails (and slugs!) live here.

For starters, there are a few California natives, like the shoulderband snail, which uses “love darts” when reproducing. (But that’s a story for another day.) There is also the chestnut snail, whose shells — fun fact — smell a little like chocolate.

California shoulderband snails (Helminthoglypta tudiculata), as the name suggest, are native to California. They’re also called Southern California shoulderbands or Southern shoulderbands. Photo by Matthew Salkiewicz.
The San Gabriel chestnut snail (Glyptostoma gabrielense) smells a little bit like chocolate. Photo by Cedric Lee.
The common garden snail (Cornu aspersum) is what you could be eating if you order escargot at a French restaurant. Photo by Cedric Lee.
Milk snails (Otala lacteal) are native to Europe and parts of North Africa. Photo by Chris Mallory.
Originally from Europe, milky slugs (Deroceras reticulate) are now common throughout the United States. Photo by Cedric Lee.

These European snails (and slugs!) easily adjust to life in Los Angeles, where it never gets too cold for their vulnerable, soft bodies; if they found their way to a place like Michigan, they wouldn’t survive a single winter.

“There are species you find everywhere with Mediterranean climates,” explains Vendetti. “South Africa. California. New Zealand. Our guide books are almost interchangeable.”

But just how do such notoriously slow-moving creatures travel the world so efficiently?

Some snails (and slugs!) hitchhike in shipments of fruits and vegetables. Other stow away in shipments of Italian tile, such as limestone. Snails love the stuff because it’s made of calcium carbonate — the same substance their shells are made of. Always on the lookout for sources of calcium to maintain their shells, the snails might take up residence between pieces of tile, only to wind up in a shipping container and making a voyage to a whole new world without realizing it.

We also know that some introduced snails, like the European garden snail, were brought here to be farmed for escargot and escaped. And while the concept of a snail escaping sounds a bit ludicrous, consider that baby snails are incredibly tiny and able to fit through small spaces. And as hermaphrodites (having both female and male anatomy), any two snails are capable of reproducing. They actually fertilize each other, and both snails leave the encounter and lay eggs. They’re very efficient, those snails.

While she takes stock of the local snail and slug scene, Vendetti is also interested in some big questions about these little gastropods (the group that includes snails and slugs). How can we tell different species apart? What makes them unique? How are all these snails and slugs related to one another?

To find out more about these Los Angeles snails and slugs, Vendetti often turns to their DNA for answers.

“The amount of genetic data for many of the native and even introduced species is limited or nonexistent,” says Vendetti. “We can use citizen science efforts to document biodiversity and gather snail DNA to assess genetic differences within a population (especially of native species that may be threatened) as well as comparing their genes to those of potential relatives.”

Snails (and slugs!) are perfect candidates for citizen science projects, where members of the community work with scientists to conduct research. You can be a part of it! Take pictures of these little gastropods and submit them to the SLIME Project (Snails and Slugs Living in Metropolitan Environments). Find out how!

Luckily, it’s very easy to collect DNA samples from these animals. All it takes is a quick swish of a cotton swab across their slimy bodies. By taking samples from different groups of snails and slugs around Southern California, she can unravel the story of these marvelous molluscs.

“You can use genetics to ask what populations they came from,” said Vendetti. “We might have European garden snails from around L.A. that were all introduced from different places at different times. Theoretically, it could be that you could genetically tell that one population is French, and another population has its roots in Spain.”

But no matter where they came from, they’re here now, and we need to study them and understand how they interact with our local snails. And as for those, is Vendetti worried about our homegrown snails and slugs?

“It’s amazing to me we have what we have here considering the development and sprawl,” said Vendetti. “I wouldn’t be super concerned that introduced snails are going to hurt our native populations in most urban environments, because you wouldn’t expect our native snails and slugs to make it in L.A. anyway! If you need rocks and undisturbed oak woodland to live in, that’s not what you’re going to get in downtown Los Angeles. Our local snails will be OK if their habitat is left intact.”

The chestnut snails surely will be relieved to hear that.



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