Winning Snails and Slugs

May 12, 2017

The results of our record-breaking #SnailBlitz 2017 are in! From tiny eggs, to monster snail jaws, people were paying careful attention to these often overlooked land-loving molluscs. These prize-winning photos, selected from 1,619 observations that were submitted by over 280 citizen scientists in February and March, include some unusual details, interesting interactions, and lots of slime. Speaking of slime, these SnailBlitz 2017 observations will all be included as biogeography data points in our ongoing SLIME Project, giving us a unique opportunity to study the distribution of these species with the help of our growing team of citizen scientists.

And this year's winners are...

Grand Prize Winner: Image by @ajzellmer

Slug eggs!  Here are (likely) two species of slug eggs and one snail, Discus rotundatus.

Runner up: Image by @finatic

Three for one. This photo shows the native snail species Rothelix lowei (far right), slug Limacus flavus (center), and a salamander (left).

Best Snail Photo Winner: Image by @alex_bairstow

This photo shows a possible predatory encounter between Rumina decollata and Cornu aspersum. Rumina decollata was specifically introduced to control populations of Cornu aspersum that were eating Southern Californian citrus.

Runners up: both by @alex_bairstow

Look at those snail jaws (common garden snail, Cornu aspersum)!
Predatory decollate snail, Rumina decollata, pretending to be a faucet?

Best Slug Photo Winner: Image by @dlbowls

Hold on for the ride buddy! This photo shows a species of Deroceras, the smooth land slug with its slime trail, and an accompanying aphid.

Runner up: Image by @kimssight

Photo of another smooth land slug, unidentified species of Deroceras.

Rarest Snail/Slug Photo Winner: Image by @silversea_starsong

This photo shows an unidentified species of slug—an observation that inspired much conversation among iNaturalist users.

Thank you to all who participated in #SnailBlitz 2017, we look forward to seeing even more slimy photos next year!

(Posted by: Jann Vendetti)

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Beneath the Perch

June 23, 2017

L.A. We Need You For Snail (and Slug) Science!

March 23, 2017

SnailBlitz 2017 is in full swing and concludes at the end of March. Our goal is to get 1,500 photos of snails and slugs from over 250 people. So we need your help! The iNaturalist observations so far have been and fascinating and beautiful! Here are some highlights:

Rumina decollata, the Decollate snail, non-native. These images show juveniles with the apex, or top, of their shell still attached. The one adult (bottom right) is missing the apex of its shell, as is characteristic of these snails when mature.

Thanks to citizen scientists silversea_starstong, alex_bairstow, and madtiller.

Ambigolimax sp., non-native. There are two species of Ambigolimax in Los Angeles County and it is impossible to tell them apart by their body patterns. Here is a selection of individuals (possibly of both species) that show some of the variation present in these slugs.

Thanks to citizen scientists cedric_lee, jaykeller, jkang5678, and jafuentes.

Chestnut snail, Glyptostoma gabrielense, native. Here are two Glyptostoma gabrielense snails, of one of greater Southern California’s native species. Not much is known about this species, but today it spans the San Gabriel Mountains, foothills, and canyons where it is generally rare. In the 1940s, there was a population that lived in the Dominguez Hills and Elysian Park neighborhoods, but there are no records of this species in either of those localities today.

Thanks to citizen scientist pileated.

Keep the observations coming! Participating is easy, and there are prizes for the best photos submitted!



(Posted by: Jann Vendetti)

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Beneath the Perch

June 23, 2017

Your New Year's Resolution: Look for more Snails and Slugs

January 3, 2017

It is a sparkling New Year! But have you sat down and thought long and hard about a New Year's resolution yet? We know that they can be overwhelming, and some people think they're cliche, but we are here to help. The only catch is, it might be a bit unconventional...

NHMLA's recommended New Year's resolution:

I will dedicate my waking hours to looking for snails and slugs in Southern California.

Keelback slug (Genus Ambigolimax) emerging from a stinkhorn mushroom (Family Phallaceae), found in NHMLA's Nature Gardens.

Here's how to get started:

1) Go outside (after it rains can be particularly fruitful).

2) Look for snails and slugs. Damp spots are best--under bushes, among wood pieces in wood piles, between and under rocks or bricks, on tree bark, on plants, among leaves, along wet sidewalks, and popping out of mushrooms! Remember if you flip a log or rock, put it back the way you found it (it is likely an animal's home).

3) Take pictures of any snail and slugs you find. Snails and slugs move slowly, so it is fairly easy to take multiple shots that are in focus. Also, try to take pictures from different angles, particularly for snails. Getting images of the top and sides of the shell can be helpful. If it is a snail-less shell, they can often still be identified. Try to get an image of the shell opening. Don't forget to take note of where you are and the day/time.

4) Send us your pictures. You can submit them directly to iNaturalist (using the free smartphone app, or on your home computer), e-mail them to, or tag them #natureinLA on social media.

We are interested in any and all snail/slugs you might find. But because you are not going to do anything by halves with your New Year's resolution, keep on the look out for these five species. If any of these were found in Southern California (and submitted to the SLIME project) they would be new records for the region. They are all native to far off places but may be closer than we think... 

Common names: Zachrysia provisoria-Cuban brown snail, Meghimatium bilineatum-Chinese slug, Parmarion martensi-yellow-shelled semi-slug, Boettgerilla pallens-worm slug, and Veronicella cubensis-Cuban leatherleaf slug.

(Posted by: Jann Vendetti)

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Beneath the Perch

June 23, 2017

Mutant Snail!

September 10, 2016

Take a close look at this Brown Garden Snail, Cornu aspersum. Instead of the usual two optical tentacles (a.k.a. eye stalks), this snail has three! The photo was sent to us by one of our citizen scientists, Rhondi Ewing and added to our Snails and Slugs Living in Metropolitan Environments project. There aren't many records of land snails with this sort of mutation, but a number of sea slugs (nudibranchs) have been recorded with forked appendages. Check out the iNaturalist page Amazing Aberrants. The project aims to collect observations of any "organism that differs in colour pattern or another visual trait due to genetics. This includes any albino, leucistic or melanistic creature as well as gynandromorphs." 

p.s. Gynandromorphs are organisms that exhibits both male and female characteristics. 



(Posted by: Lila Higgins)

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A Microscopic Look at Snail Jaws

July 5, 2016

Have you ever wondered what the inside of a snail's mouth looks like? 

The anatomy involved in land snail and slug feeding is fascinating. Well, I’d like to guess that it is more fascinating than you’d expect, if you’ve ever thought about snail and slug feeding in the first place. Snails and slugs have evolved to eat just about everything; they are herbivorous, carnivorous, omnivorous, and detritivorous (eating decaying waste from plants and other animals). There are specialist and generalist species that eat worms, vegetation, rotting vegetation, animal waste, fungus, and other snails.

Brazilian snail eating lettuce.

Thousands of Microsopic Teeth!

Snails and slugs eat with a jaw and a flexible band of thousands of microscopic teeth, called a radula. The radula scrapes up, or rasps, food particles and the jaw cuts off larger pieces of food, like a leaf, to be rasped by the radula. To understand what the single jaw and radular band look like in a terrestrial snail, two Museum interns (from Glendale Community College), Ala Babakhanians and Richard Laguna, photographed a common European Garden Snail (Cornu aspersum) eating a film of cornstarch and water on a piece of glass. This clever method was inspired by the Snail's Tales blog

Underside of Cornu aspersum showing the single reddish-brown jaw of the mouth.

Close up of the open mouth of Cornu aspersum showing the jaw and the pale-colored ribbon of teeth called the radula.

A Close Look at a Slug's Rasping Radula

The only way to truly appreciate the microscopic teeth of the radula is to look at them under a microscope. To do this, Ole Willadsen, another Glendale Community College intern at NHMLA, dissected out the radula from a non-native slug found on Sunset Boulevard.

Limacus sp., non-native slug found in Los Angeles by Cedric Lee.

The radula was imaged using the Museum's scanning electron microscope (SEM), which creates an extremely detailed and highly magnified picture of the specimen examined.

SEM image of central radular teeth Limacus sp. specimen shown above. 

SEM image of marginal radular teeth Limacus sp.

The fascinating feeding anatomy of snails and slugs is also helpful in determining their species identity, if and when that is in question. Since we sometimes don’t know the identity of non-native species we encounter in Los Angeles, the size and shape of their single jaw and thousands of radular teeth can be as informative as they are beautiful.

**Can you hear a snail eating? Yes! Check out Elisabeth Tova Bailey’s book The Sound of a Wild Snail Eating.

If you’d like to be involved in efforts to document and protect L.A.’s biodiversity, check out our Citizen Science program. Or you can donate to the Urban Nature Research Center.

(Posted by: Jann Vendetti)

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Beneath the Perch

June 23, 2017

El Niño #SnailBlitz Finds Rare Tight Coil Snail in LA!

April 26, 2016

Although we had less than average rainfall this winter, SLIME citizen scientists became iNaturalist superstars and logged 1,225 observations of Southern California's land snails and slugs for our El Niño #SnailBlitz

There are many highlights from the effort, but of particular note is this rare snail.

Tight Coil Snail (Pristiloma sp.)

This Tight Coil snail was found by Cedric Lee, on March 20, 2016. He found it in the San Gabriel Mountains near the Pacific Coast Trail. It is likely Pristiloma gabrielinum or Pristiloma chersinella, both species are native to Southern California, but are difficult to tell apart. These snails are TINY: less than half the width of a pencil eraser at around 3 mm in diameter. Pristiloma gabrielinum is considered critically imperiled and Pristiloma chersinella is listed by NatureServ as a vulnerable species.

VERY little is known about the biology of either of these snails. Cedric's comment that he found it under the bark of a fallen pine tree adds to the basic understanding of how these snails live.

...and other interesting finds:

Tawny Beehive Snail (Euconulus fulvus)

This Tawny Beehive snail was also observed by Cedric Lee, on March 20, 2016 in the San Gabriel Mountains. This photo is the first I've ever seen of its kind alive! 

Small Pointed Snail (Cochilcella barbara)

This snail was observed by Emily Han, on April 8th and 10th, 2016 in Mount Washington. Previously, only known from nearby San Diego and Santa Barbara counties, this observation is the first record for Los Angeles County!  This snail has a Pest B rating by the California Department of Food and Agriculture, which includes the prediction that this snail is highly likely to become established widely throughout the State. Only nine samples of these snails have been identified in California over the last 40 years, making this observation the 10th. Emily found these snails in abundance, which means their population is likely well-established.  

A Possible Budapest Slug (Tandonia sp.) 

I found this slug on March 16, 2016 while doing a #SnailBlitz hunt with Ms. Griffith's 8th grade science class, at Arroyo Seco Museum Science Magnet School in Mount Washington. This slug is a conundrum! Either is it a variant of the more common non-native slug, Milax gagates, or it is of the genus Tandonia, which would be a county and possibly state record. Because internal anatomy and/or DNA analysis are the only ways to determine the identity of this slug, this animal was sacrificed and tested for its barcoding gene (called CO1) and dissected to specifically look at its reproductive anatomy. Results are forthcoming.

The Unnamed Slug (Hesperarion hemphilli) 

This unnamed slug was observed by Annette Mercer and Brian Brown, on February 20, 2016 in Griffith Park. As mentioned in a previous blog post this species is a Southern California native and is so poorly known it doesn't even have a common name! 

Snail Behavior 101

And finally, some photos displayed snails galloping (technically called loping)! Citizen scientists @littlecrane13 and Rob Kutner and Sasha Kutner (age 7) observed Cornu aspersum moving with a loping gait, in which the snail makes a dashed line of mucus instead of a continuous one. What is fascinating about this behavior is that snails will lope when moving on dry surfaces like concrete or wood, but not on a smooth surface like glass.

Loping and adhesive crawling (when a snail or slug leaves a continuous slime trail) move the snail at the same pace, but loping uses less mucus and possibly saves the snail from getting too dry when moving on a porous surface. Rob and Sasha Kutner observed loping on concrete and @littlecrane13 observed this phenomenon on tile.

These and other observations are not only fascinating, but scientifically important. The photos taken are data points of biological diversity and species distribution. Many are also exquisitely beautiful, showcasing these animals as they are often not seen or appreciated. El Niño #SnailBlitz was a great success, thanks to all the citizen scientists out there. While the #SnailBlitz is now over, the SLIME project continues. So keep the observations coming! 


(Posted by: Jann Vendetti)

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Beneath the Perch

June 23, 2017

Meet Some of Your L.A. Native Snails and Slugs

March 22, 2016

As I write this in mid March, Southern California is still in the grips of a historic draught. By the end of February, typically the rainiest month in Los Angeles, the city was nearly its hottest and driest on record and during what was predicted as a Godzilla El Niño winter. In contrast to our paltry 0.78 inches of rain this February, El Niño of February 1998 brought 13.68 inches of rain to Southern California!


A rare and native Los Angeles snail, Helminthoglpyta tudiculata, found by Museum citizen scientists. 

How does the rain, or lack of it, influence our region’s snails and slugs? NHMLA’s El Niño #SnailBlitz was created to record this fauna during our predicted rainy winter, and has logged over 530 observations of snails and slugs since January 16th (with a wrap up date of April 14th).  Given that it hasn’t been unusually rainy (yet), we haven’t documented vast numbers of snails and slugs on the wet sidewalks of our urban environments. However, one fascinating category of terrestrial gastropods (= land snails and slugs) that we have documented are those endemic to Southern California. That is, the snails and slugs that evolved here, live nowhere else, and are adapted to our Mediterranean and typically dry climate.

The first encounter with a Southern California native snail, by many El Niño #SnailBlitz contributors, was at the project’s kickoff event at Eaton Canyon Nature Center in the foothills of the San Gabriel Mountains.

Empty Southern California shoulderband snail shells, found during the #SnailBlitz kickoff event at Eaton Canyon Nature Center.

The Southern California shoulderband snail, Helminthoglypta tudiculata, was the star of this survey and although this species is at high to moderate risk of extinction, it was discovered in abundance. These snails are typically not found in your garden or on wet sidewalks. They usually live among decaying vegetation that they also eat. The cinnamon-brown shell of the Southern California shoulderband has exactly that, a characteristic band, usually darker than the rest of the shell running along its “shoulder” or outer shell whorl. Their discovery, and in high enough numbers to indicate a healthy population, was exciting news for both SLIME scientists and the public. 


Native slug, Hesperarion hemphilli, found during an El Niño #SnailBlitz event at Griffith Park. 

The publicity from the Eaton Canyon snail survey brought out 80 intrepid snail surveyors to another Museum event in Griffith Park. Though the sightings were few, the taxa found were natives too! One in particular, a slug called Hesperarion hemphilli is a Los Angeles native that was found widely distributed throughout wooded canyons of Los Angeles and Orange counties in the 1940s. Surprisingly few records have been made of it since then, and while this slug is known generally from Santa Barbara, Orange, and Los Angeles counties, the Griffith Park survey uncovered the first record of this species in the Santa Monica Mountains and only the second observation of this species on iNaturalist! Angelenos have lived near this slug for over 75 years though most have never seen it. In fact, it is so uncommon and underappreciated, that it doesn’t even have a common name!

Snail scientist Jann Vendetti with junior snail surveyors at Griffith Park in prime snail and slug habitat. 

So, keep your observations coming, rain or shine. Our native snail and slug species are an understudied group and your observations are vital to understanding our local molluscan biodiversity. Contribute snail and slug observations to SLIME via photos to, post on Instagram, Facebook, or Twitter tagged with #SnailBlitz, or upload directly to the El Nino #SnailBlitz project on iNaturalist.

(Posted by: Jann Vendetti)

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When it Rains in L.A.: My Quest for Mushrooms, Snails, and Dog Vomit Slime Mold

February 2, 2016

You know that earthy smell that comes just as it begins to rain after a dry spell? It has a name. Scientists call it petrichor.

When I smell petrichor, I get excited: Rain is a personal and professional obsession. I begin keeping close tabs on the window while I check weather reports for the forecast. As the manager of citizen science (getting the community involved in scientific studies) at the Natural History Museum of Los Angeles County, I start making a list in my mind to share with others. What mushrooms and slime molds and snails and slugs will I be likely to find? I imagine all of the places I should check to find these uncommon organisms that only come out when the soil is moist.

Brown garden snail, found in Hancock Park.

Where I grew up—England—rain was not at all a rare event. As a kid, I’d follow the slime trails of snails to chase them down among the bushes, then carefully take them to the designated snail house—a crook in a tree. Somehow the snails would always escape! I would walk across the farm fields around my house looking for mushrooms growing in circles, which my grandma told me were called fairy rings.

One day I was exploring a hollow tree and a huge puffball mushroom exploded in my hair. It happened as I climbed up inside the dark recess and spotted a large creamy white orb about the same size as my 7-year old head. As I wiggled through the hollow, trying to pull myself through, I brushed against the puffy mass and it burst. It was white and gooey and made my curly hair stick to my head. My family thought it was hilarious.

In Los Angeles, I have to wait months and months for a good rain. With El Niño 2016 upon us, I am on alert for the new slimy city that springs up after a rain, whenever I hike, walk to the bus stop, or bike through Koreatown.

Fungi live most of their lives underground, hidden from our eyes. Here in the arid Southwest they are easy to miss, only showing themselves for the briefest of moments after rains, or on irrigated lawns and mulched garden beds. Hiking in Griffith Park after a storm, I look along the sides of the trail hoping to spot spectacular fruiting bodies—what most of us think of as mushrooms. In Southern California, there are almost 400 species of fungi, including wicked poisonous ones like the western destroying angel, and delicious chanterelles, which sell online for $24 a pound. If you are really lucky you might even stumble upon a jack o’lantern, a bright-orange-gilled mushroom that glows in the dark! This is real bioluminescence. It contains the enzyme luciferase, the same as in fireflies.

A few years ago, I found a puffball mushroom in Griffith Park. It was much, much smaller than the one that popped on my head as a child, but I still couldn’t resist taking a closer look and marveling at the white bumpy flesh. This time, I touched it with my finger—and a faint puff of brown “smoke” seemed to be exhaled. Just like a raindrop, I had triggered the spores to release so the puffball’s genetic material could carry on.

Slime molds are even more alien than fungi and just as fun to hunt down. Take the dog vomit slime mold, for example. The name comes from its common incarnation as a bright yellow or pink oddly puffy aggregation on lawns, paths, or walls. It can be found all over the city, and I’ve found it in mulch along the L.A. River, and in planters in Koreatown. Most of the time the dog vomit slime mold lives as a single cell, surviving underground or inside dead wood and engulfing food. It’s when times are tough—for instance, when they run out of food—that the cells come together to move around in these large masses called slugs. Scientists have been studying their movement—watching them solve mazes or making them grow interstate highway systems on maps! After the slime mold goes through sexual reproduction, they produce and release spores and then turn black. The spores are caught by the wind and blown away, landing on new territory where they can go through the cycle again.

Dog vomit slime mold, found in a Koreatown planter. 

Thirty years later, I am still chasing snails. A few days ago, after a rain, I went on a work field trip with museum herpetologist Greg Pauly in search of snails and slugs. In celebration of the museum’s SLIME (Snails and Slugs Living in Modified Environments) project and our El Niño #SnailBlitz, I was bent on getting pictures for this citizen science project. We strolled through West Coyote Hills in Orange County and kept our eyes peeled. At the bottom of a mountain biking trail, Greg and I began gently flipping over old bits of rubble.

After 30 seconds, we found snails. I took a look and immediately thought they might be interesting. They didn’t look like the regular brown garden snails (the big ones that were introduced from Europe for escargot) that are found all over town. Instead, they had a chocolate brown stripe that followed the swirl of the shell and they had a much darker body. We took pictures, hoping we could get the snail identified by the museum’s malacologist—a.k.a. snail/slug/clam/squid/octopus scientist—Jann Vendetti. Later that evening I got a two-word text message from Greg.

Helminthoglypta tudiculata

Southern California shoulderband snail, found in West Coyote Hills. 

These are the types of texts you get when scientists are your friends. Greg had shown the photo to Jann, and she had been able to make a positive identification. These two words carried a lot of weight. It meant the snails we found were native Angelenos—Southern California shoulderband snails, to be exact. It meant we had found another population of this under-studied group. It also meant the pictures Greg and I had taken could be valuable citizen science data points. We both shared our photos to the SLIME project on iNaturalist (like FaceBook for nature nerds) so Jann can better study these snails, which are at risk of extinction. Our local native snails are L.A.’s version of the canary in the coalmine, if the snails are not doing well, our environment is not doing well.

When it’s very hot or dry, snails aestivate—which means they retreat into their shells to use as little energy or water as possible. Some species can even excrete a liquid that becomes a barrier—Jann calls it an epiphragm—sealing themselves (and their moisture) inside. And then they just hunker down waiting for the rain to return.

A rain shadow in the Museum's Nature Gardens. 

Sometimes I’m so excited when the rain returns that I lie down on dry pavement or dirt, so the rain can darken the ground around me to make a “rain shadow.” I’ve noticed that some raindrops feel sharp and prickly; others splash on my face in huge droplets. As I lie on the ground and really feel the rain, I wonder, what must this feel like to other creatures, who’ve been waiting so long for this manna to fall from heaven?

This essay was originally written for Zocalo Public Square.

*All photos by Lila Higgins

(Posted by: Lila Higgins)

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Beneath the Perch

June 23, 2017

Land Snails: The Key to Beauty?

November 2, 2015

Snail slime has many names-snail mucin, snail secretion filtrate, or just plain snail mucus. But is it going to save your skin? 

Snail slime has hit the beauty market in spectacular fashion, enhancing face creams, moisturizers, gel masks, and skin repair serums. South Korean cosmetics companies have been at the forefront of this trend with claims that these snail slime products reduce wrinkles, repair damaged skin, improve acne scars, and lighten dark spots. So, from what magnificent snail comes this “miracle” beauty product? 

The common garden snail. 

Tonymoly Intense Care Snail Hydro-gel Mask with its “creator,” Cornu aspersum. 

It's scientific name is Cornu aspersum, and if you’ve seen a snail on the sidewalk after a rain, chances are it is this species. It's not only common in Los Angeles, but thrives as an introduced species far beyond its native Europe. Check out  the over 650 observations of this species on iNaturalist from Van Nuys to New Zealand. 

Garden snail slime, as an ingredient in “cosmeceuticals” (a hybrid cosmetic and pharmaceutical product), is collected from live snails, filtered, then added to other ingredients to make various skin products. Some of which show promise in small studies to heal sunburn and accelerate wound repair. In analyses of snail slime, cosmetics researchers discovered that the garden snail has five types of mucus cells, each of which produce a unique mix of chemicals, including one of the darlings of the skin-care industry, glycosaminoglycans, or GAGs. These molecules attract water and are therefore often used in moisturizers to plump up skin. 

When referring to Cornu aspersum, snail slime product labels use creative names including “black snail” or “Chilean earth snail”, which presumably sounds more exotic than “common garden snail.” One product hails the species’ “ever-resilient” qualities and notes that it is “lauded for its ability to survive harsh environments.”  In more scientific sounding contexts, it is referred to as “Cryptomphalus aspersa”, a mostly un-used alternative name, or “Helix Aspersa Müller,” also incorrect as Helix is now considered an out-of-date genus name and aspersa, the species name, should be written in lowercase in italics. 

The story of the naming and re-naming of this species by biologists since the late 1700s deserves its own discussion, which you can find some of here. One of the major players in that story is Otto Friedrich Müller, a Danish naturalist who first described this species in 1774. This is the very same “Müller” sometimes tacked onto the end of the species name, by convention. I would like to think that Otto would be amused to know that 240 years after he described this species, its slime is “beautifying” faces across the globe.  

Many thanks to Su Oh, Natural History Museum of Los Angeles County, for bringing the beauty product at the top back from Korea. 

(Posted by: Jann Vendetti)

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Introducing Your Los Angeles Snails!

September 25, 2015

There is a new citizen science project in town and we need your help to document the snails and slugs that call Los Angeles home. SLIME (Snails and Slugs Living in Metropolitan Environments) kicked off earlier this year, and we are already making some interesting discoveries about life in L.A.'s slow lane. 

White Italian snails on a sprinkler at the White Point Nature Center, San Pedro, Los Angeles County. Notice the variation in color and pattern. Photo by Austin Hendy.

There are about a dozen common land snails in Los Angeles County. If you’ve hiked within the Palos Verdes peninsula, or up to the Baldwin Hills Scenic overlook you’ve probably seen two of the most common snails in urban Southern California. Like most Angelenos, they thrive in a Mediterranean climate and, in fact, ARE from a Mediterranean climate. The white Italian snail (Theba pisana) and milk snail (Otala lactea), hail from Southern Europe and reproduce abundantly in our neighborhoods, their adopted home. They are often found clustered on the same plant stem, sprinkler, sign, or fence, and in numbers from the dozens to hundreds.

Despite this presence, and close proximity to people in Los Angeles parks and along hiking trails, they are often confused for each other or misidentified as other species. Here's why. 


Both are highly variable in color and in pattern. The next time you seen a bunch of them, take a close look. In white Italian snails, shell color can range from white to tan with varying degrees of banding, zigzags, and stripes of variable thickness. 

Likewise, the milk snail’s shell can range from almost totally white to heavily banded with brown and tan stripes, which can be solid or stippled. And, to add to the confusion of the casual snail-watcher, these species sometimes overlap in habitat, as in the gardens of the White Point Nature Center in San Pedro.

Milk snail on a twig at the White Point Nature Center, San Pedro, Los Angeles County. 

So how do you tell the difference?


The white Italian snail (Theba pisana) is the smaller of the two species and at maturity is about the size of a dime. As an adult, its umbilicus, or the center of the underside of the shell, is partially covered by the lip of the shell.


The milk snail (Otala lactea) is the larger of the two species and about the size of a quarter at maturity. As an adult its umbilicus and part of the underside of the shell is glossy and brown in color. 

Easily distinguing a milk snail (left) from a white Italian snail (right) by examining the underside, or umbilical view of the shell.


Such confusion is not limited to sizable snails you’d find hiking, but makes distinguishing two tiny Los Angeles snails tricky as well. If you look under rocks, among leaf litter, or in the soil of potted plants, you might find two more snail doppelgangers: the orchid snail (Zonitoides arboreus) and the glass snail (Oxychilus sp.). They share the same two-toned gray-colored bodies, and flattened amber-colored shell, but can be distinguished by size and subtle differences in the shell.  

Glass snail (top) and orchid snail, tiny snails with subtle differences. 

When in doubt, which is most of the time even for seasoned snail observers, the best way to photograph a snail for identification is to take images of the shell from three different angles; the top (apical view), the side (apertural view), and the bottom (umbilical view).

The 3-view approach to photographing milk snails apical (top), apertural (middle), and umbilical (bottom) views.

So next time you find a snail (or slug for that matter) take pictures and send them into the SLIME project. You can submit them directly to iNaturalist, e-mail them to, or tag them #natureinLA on social media. Either way, you will be able to put your new-found snail identification skills to the test, and I might get to help with the tricky taxonomy of terrestrial molluscs.


(Posted by: Jann Vendetti)


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