We didn’t set out this spring to document as many snails as possible, but that’s essentially what happened. During the winter of ’23-24, we were based in one of our favorite spots, the remote community of Fernbrook, in San Diego County. Normally, the winter is full of mushrooming and tidepooling, but this year, we ended our winter and spent a chunk of our spring hunting for all the snail species we could get our eyeballs and camera on.

It just so happened that the annual Snail BioBlitz, which is run by the LA County Natural History Museum through an iNaturalist project, was going on again. The project focuses on Southern California snail records between January 27 and March 31, 2024. We ended up contributing 30 species to the project, the most recorded by any participant.

Funny enough, it’s hard to really count how many snail species we’ve recorded between late Dec ’23 and mid-April ’24, but it’s roughly 54 species. A few identifications don’t have confirmation, which we hope to get in the future.

This blog post is broken up by California counties, and the snails we found within them. But first I wanted to spruce up any readers on snail anatomy basics, and some snail natural history for context.

Snail Anatomy, the Basics

Sculpture refers to the surface features of the shell, think the texture of the shell of a mollusk. Sculpture also refers to if the surface has raised parts that can be concave or convex, but does not refer to the actual shape of the shell or coloration.

The main hole where the snail’s body pokes in and out of is the aperture.

Whorls refer to the twirly spins of the shell. Some shells have more than others. The lines that define the whorls are called sutures.

The umbilicus refers to the “armpit” of the shell. When you flip a shell over so you see the “bottom” the innermost deep point is the umbilicus.

Now the opposite of the umbilicus, or the tippy top of the shell is the apex, think the highest point of the top of the shell.

None of these snails have an operculum, or at least what I recall seeing. But you may come across a snail with a thin disc-like door that closes when the snail is fully inside the shell, which is known as the operculum. Some describe it as a “trapdoor.”

Desert Snail Natural History

Many of the snails included in this blog are desert-dwelling snails. If told ‘think of a snail and it’s home’ a desert environment would not be top of mind for such a slimy-ish creature. Snails are obviously, and most often associated with sidewalks after rain or deep in forests’ cool and deep corners. Definitely not a desert. . . .

To survive the relentless tough conditions of the desert, snails are active during the winter and then enter dormancy during the rest of the year to prevent desiccation. But when it does rain, out come the snails in search of food, a mate, and to lay eggs.

Many factors can determine where exactly these snails hang out, but generally north-facing rocky environments with areas where they can go deep within the hillside when it gets hot is a good place to look. But factors like humidity, topography, food availability, and local precipitation can all be factors in connecting with a desert snail. Food can include cyanobacteria, algae, microfungi, lichens, and mosses.

Generic Land Snails

Snails “live primarily in the upper leaf litter of forests, old fields, and wetlands, but also in more disturbed habitats such as active gardens and fields, river banks, suburbs, and even cities” (Land Snail Ecology). In the two places, we found forest-dwelling snails they were mostly in or under logs, and some were under rocks of various sizes.

Food sources include “organic material, mainly green or dead herbaceous plants, rotting wood and fungi, bark, and algae, but they also consume empty snail shells, sap, animal scats and carcasses, and even rasp limestone rock or cement. Carnivorous snail species attack nematodes and other snails.
Predators of snails include invertebrates such as parasitic mites, nematodes, and flies; beetle larvae, beetles, and millipedes; and other snails. Vertebrate predators of snails and slugs include herptiles such as salamanders and turtles; shrews, mice, and other small mammals; and birds, especially ground-foragers such as thrushes, grouse, and turkey” (Land Snail Ecology).

Most people know that snail shells are mostly made of calcium. Where does the calcium come from? Their food! The calcium is then concentrated in their shells, which are primarily calcium carbonate. The calcium is passed up the food chain when predators eat the snails. So snails are one part of the carbon cycle in any given ecosystem.

“Land snails do not move far over their lifetime, so they can be excellent indicators of site history and site conditions. Because shelled land snails have a high calcium demand, they are sensitive to calcium availability due to soils and plants. Site moisture and past land clearing or fire also strongly influence snail populations. Land snails have been used extensively in European archaeology to interpret environments of the distant past. They can also be indicators of pollution, as they uptake environmental toxins such as cadmium” (Land Snail Ecology).

San Diego County

Searching for this Sonorelix harperi led us to a desert oasis. After combing the surroundings, going up and down large boulders, and crawling along the oasis walls, one live individual was found deep under a rock ledge, which you can see in the bottom right photo. Take a look at the white shell, which is roughly 16mm across, in contrast to the black body, which is quite unique amongst the snails in this blog.

All praise for finding this snail goes to Trevor, who worked hard to find this Anza Shoulderband Snail on Hot Springs Mountain at ~1800m (5900ft). Tucked under an oak log in a plant community of incense cedar, black oak, canyon live oak, bigcone Douglas fir, and white fir is what this rare snail calls home.

San Bernardino County Desert

On my way home from a trip to see family in Vegas, I successfully found the Fulton’s Desertsnail Cahuillus fultoni at its type locality, which is near Zzyzx. It took about 45 minutes of scrambling up and down a hillside to start feeling like I might need to give up, as I had other snails to search for that day and a long drive back to Fernbrook. So I decided to switch my efforts to the wettest parts, which were near the road, and !boom! I found these shells underneath one of the larger boulders near the road, not far from the parked car. Of course. . .

This species was first collected as shells in the late 1980s, and live specimens were found in 1993 by Robert Fulton. . . fultoni. For a short article on the story behind its description in 2013, read this Mojave National Preserve Science Newsletter article.

Channel Islands: Santa Catalina & Santa Cruz

Now for our time in the Channel Islands! To read an overview paper on the land mollusks of California’s Channel Islands, check out this paper from 2018 by Drost et al..

During the first trip of two to Catalina Island we took this year, we had to deal with some island shenanigans, which involved the trails being closed due to recent rain for a whole day, so when we finally got out on the trails and started to find these Catalina Cactus sails it was so satisfying! It was the start of searching for the many different islands endemic to Catalina Island and the greater Channel Islands. Perhaps the name gives it away, but this snail can only be found on Catalina Island.

Both trips to Catalina resulted in finding Avalon Island Snails, perhaps the most abundant snails we encountered while tromping around the island. During our second trip to this *cough* mismanaged island, I found oodles of cracked shells under a large rock’s ledge. The Avalon Island snail can only be found on Santa Catalina Island.

Take a look at this is very small snail that was found within island oak leaf litter. During our first trip to the island, we rented an Airbnb, which opened up the possibility of sifting litter while there, and that’s exactly what occurred. We packed a Berlese funnel in our backpack and sifted litter overnight, which resulted in this tiny snail and other normally impossible-to-find insects.

Lucky dip. There are a few snails where the first log flip of the day resulted in connecting with the targeted snail. That’s what happened with this Santa Cruz Island snail, which can be found on Santa Cruz and Anacapa Island.

Kern County

Do you see the babe?! I mean the. . .immature individual in the bottom left photo? Precious! These two Sonorelix micrometalleus were found under a rock in north-facing granite cliffs in Last Chance Canyon, which is in the Red Rock Canyon State Park area.

We’ve been to this canyon before to find some plants, but this round was strictly to find this snail. The canyon is technically a “trail” for off-roading vehicles, but probably the craziest canyon trail we’ve encountered. How vehicles get through there is impressive, and I am no fan of these habitat-destroying vehicles in general. Do I sometimes wish we had access to one to travel long distances across remote areas. . .can’t say I haven’t thought of it as the sweat drips down into my eyeballs.

This lovely snail, the Mojave Shoulderband Snail, was found in small rock outcrops near Soledad mountain. We only found this one living specimen, but we only searched maybe 15-20 minutes.

Like other desert dwellers, little is known about this species natural history. But we know some things, and we can guess some things based on other desert snails. Interestingly, according to a “Species Status Assessment for the Mohave Shoulderband Snail” by the US Fish and Wildlife, this species eats rock-dwelling lichens. I’ve heard of them eating other things like “cyanobacteria, algae, microfungi, lichens, or mosses” (also listed as potential food sources), but not yet lichen! Add it to the list!

Another find that can only be attributed to Trevor. These Tehachapi Shoulderbands were found under valley oak debris. It might be hard to tell but these are quite round and chunky little shells.

Ventura County

Another Shoulderband, the Matilija SS took some effort to find, but it sure was glorious when we connected. We were nearing the point of giving up because good habitat was dwindling, and the sun was about to set in the valley we were camping in. But waaazzzaaaa, success! On the same day, we also might have run into this species, but at a different site under a downed Sycamore tree, but we are not fully confident in the identification. So, if you know this species well, we’d appreciate any identification help.

Inyo County

During our March trip to Death Valley NP, we searched Titus Canyon for this snail, Eremarionta argus, and thankfully, we were successful! It was a very long and windy hike up the canyon to this spot, where Trevor, with his classic determination, really put in some extra effort by scrambling up a hillside to find this live specimen. Several other shells were found nearby along a north-facing dolomite cliff.

“Commoners” of SoCal

Not all the snails we pursued were rare; in this section, I present some of the more common snails we found while in Southern California.

For whatever reason, Trevor thought we hadn’t seen this species before, so we went looking for it during the day before our backpacking trip on Santa Cruz Island. Well jokes on us, we had three observations of the Zaca Shoulderband already up on iNaturalist, one living specimen, and two shells.

For this stellar-looking individual, we had to put in some effort, and just before being almost out of real estate (and patience), I crossed the creek we were searching along, spotted a log, and started looking through it, and boom, hellllooooo. The mottling pattern on the shell, along with this being a large snail overall just made the whole snail quite striking in appearance, definitely moreso than others.

Like many snails in the post, they are at some level of vulnerability, this one among others is labeled as “critically imperiled” in the US. Depending on where the snails are found, how hard their habitat is to reach, how common they are in their habitat, their seasonality and other factors can determine how many iNat observations are recorded. For this species, it has over 100 observations, for others in this blog post it’s often less than 5. Whether or not they are deemed “more threatened (at risk of extinction)” than others doesn’t necessarily mean they are harder to find, something that might surprise any non-nature folks.

During a search for a legless lizard, this Trask Shoulderband Snail appeared during a board flip. This species is found through LA, down south as Ensenada in Baja California.

On the left is the Southern California Shoulderband Helminthoglypta tudiculata Endangered. It was found on the property we were living on during a casual night walk. And similar in size, the San Diego Chestnut, Glyptostoma newberryanum is on the left. This species is imperiled, and lucky for us, we also found it during the same night walk.

NorCal Spring Snails

Yes, this post is about SoCal snails, but we moved up to Lake County (above Napa and Sonoma valleys) at the end of March, and we’ve had some great finds within this spring season.

Large, common, and red. That’s how I’d describe this and every other Redwood Sideband I’ve come across, which makes for a striking appearance. Their range goes from the Bay Area along the coast up to Southern Oregon.

When hunting for snails, this one has tripped me up multiple times. I thought it was the target species when it was just another California Lancetooth. Dang! Another “critically imperiled” species, this particular individual was found along Porter Creek Rd. It’s very flat and often clear-ish to yellow in coloration.

This snail took some effort, but like other snails, it really just took time and effort to get to the right habitat, and then it was boom, sub 10 minutes. Dodging cars on a skinny, skinny road shoulder, rifling through dumped trash along the steep hillsides in order to reach potential logs, and after giving up on multiple different sites, one last potential spot was left. Well, you’re seeing the snail, so it worked out! When we descended down from the road, the habitat already felt much much better, not so steep, and lots of woody debris; instantly, the tingly feeling that this was the right spot began creeping through our senses.

These snails and two salamander species cost us four new tires, a trip to the Santa Rosa Tesla service center to fix the suspension, and twice to another shop for proper alignment.

Chirpchatter Creek area in Shasta County, along Shasta Lake, is more likely to cause massive frustration because of the sheer length and windiness of the road than a threat to most tires. We have done this same road in the past with our Subaru Forester and will be back out there with the Tesla again soon. This time, there better be no tire shenanigans, or we might have to write the road off for good to preserve our mental sanity.

Here is the second culprit of the Chirpchatter Creek adventure, the Shasta Sideband. Read the previous paragraph for the shenanigans that ensued during this trip.

Later that day along Shasta Creek, after a trip to Les Schwab for two new tires, and just in time for a US Fish and Wildlife Service ranger to come to check on what we were doing, Trevor found this lovely snail, the Ellery Creek Hesperian. No, we were not a part of a grow-op gang, as the cop suspected, but he definitely didn’t suspect we were photographing a rare snail!

This beautiful snail was found under a chunky piece of log right next to the creek’s edge, which was itself under a mess of bramble boroughs. No one said searching for snails was easy or clean!

While I made dinner at our campground, Trevor was galavanting through the surrounding woods and picked up this (hopefully, identification awaiting) Church’s Sideband. It can be found in rocky outcrops in hardwood-conifer forests (CalPhotos).

A few false calls, a few broken shells, a few other critters, such as an arboreal salamander, scorpions, spiders, and a bit of rain all proceeded connecting with a live Silky Shoulderband Snail.

Teeny tiny boi. We found two live snails and one shell of a Scaly Chaparral. As you can see, this one is on the smaller side. It was first described in 1846 and is known from SW Oregon to central California. Looking closely at the shell, you can really see the scale-like sculpturing.

in conclusion. . .

Thank you to anyone who read this looooong blog post or just perused the photos. Hopefully, you came away with an appreciation for the diversity of snails in California and perhaps some additional knowledge on what it takes to find and document this under-observed and underappreciated group of living organisms.

The Checklist of the Land Snails and Slugs of California, Second Edition, reports that there are 279 species living in California. Of that, 37 species are not native and six additional are known only as late Quaternary fossils (Santa Barbara Museum). So we have a lot of work still cut out for us!

For those that might be interested, these two species were iNaturalists Firsts:

• Anza Shoulderband
• Ellery Creek Hesperian (if identification is correct)

No doubt there will be more snail-hunting success stories on the horizon, so if you are curious, our finds are always documented on iNaturalist.