For many people in northern Utah, there’s nothing better than a warm afternoon with family and friends at Bear Lake. You can splash in the shallows, bask in the sunshine, and stroll along the shoreline while marveling at a centuries-old legacy of ancient mollusks.
Wait, what??! Ancient mollusks, 800 miles from the ocean? Yes, it’s true.
For years, when visiting Bear Lake, I’d be fascinated by snail shells strewn along the shore just above the waterline. I always wondered why we could find thousands of shells but would never see a live snail.
Well, it turns out that Utah is home to numerous species of live snails, but the shells we see beside Bear Lake have been there for nearly 10,000 years! They’ve lasted this long because they’re preserved by the calcium chemistry of a lake that’s fed by springs and groundwater beneath the limestone crags of the Bear River Range. Many years ago, researchers from the Smithsonian Institution identified six species of snail and one species of clam amongst the Bear Lake sands, all of which thrived in a bygone era when the lake was 30 to 50 feet higher and much bigger.
The snails that occupied those shells may have died out, but they have living relatives today. Scientists say that the group of invertebrates in the phylum Mollusca includes more than 85,000 recognized species, including clams and oysters, barnacles and limpets, snails and slugs, squids and octopuses. Some can even be found in our arid, landlocked state of Utah.
If you travel the highways of Utah and surrounding states, you’ve seen signs warning against a mollusk species that we don’t want in the state: the quagga mussel. These clam-like creatures have turned up in Lake Powell and we don’t want them in other lakes and reservoirs. They’ve become a nuisance in other states, clogging pipes and water lines, and competing with native fish for food. Once they become established, removing quagga mussels or the closely related zebra mussel can cost many millions of dollars. That’s why Utah has set up boat-inspection stations across the state to try to keep them out.
Another mollusk that many people would like to be rid of is the common garden slug – also called the grey field slug and known to malacologists as Deroceras reticulatum. Slugs don’t seem much like oysters or squids, but they’re basically just snails that have evolved to get along without a shell.
Less visible are the many other species of mollusks found in our state. A few years ago, biologist Eric Wagner published the Utah Mollusk Identification Guide with descriptions of 139 species of snails, slugs, clams, and mussels found within the borders of our state. Just one year later, Eric and a colleague, Christy Bills from the Natural History Museum of Utah, published an article reporting three additional species – two snails and a slug – that had not been seen in Utah before. Undoubtedly there are more that no one has noticed yet.
Just about all of Utah’s mollusks are cryptic - a term biologists use to refer to creatures that are hard to notice. Many are quite rare. One example is the Kanab ambersnail, a dime-sized creature found only at a large spring in Grand Canyon National Park and some small ponds near the town of Kanab, Utah. Others, like the freshwater mussel called the Western Pearlshell, can be found across the West but their populations are declining.
These creatures may not be obvious, but they’re part of what makes Utah’s wild nature so varied and wonderful. Losing any one of them would be a tragedy.
I’m Mark Brunson, and I’m wild about Utah’s wild creatures, no matter how cryptic.
Credits:
Images: Bear Lake Shells, Courtesy & Copyright Mark Brunson, Photographer, as well as Shells on the Bear Lake Sand, Courtesy Utah Geological Survey, Copyright Mark Mulligan, Photographer.
Featured Audio: Courtesy & © J. Chase and K.W. Baldwin and Anderson, Howe, and Wakeman
Voice & Text: Mark Brunson, https://www.usu.edu/experts/profile/mark-brunson/
Additional Reading: Mark Brunson, https://www.usu.edu/experts/profile/mark-brunson/ & Lyle Bingham, Bridgerland Audubon Society
Additional Reading
Mark Brunson’s Wild About Utah archive: https://www.upr.org/people/mark-brunson
Beautiful UTAH: The wonderfully weird world of mollusks. The Payson Chronicle (Oct. 6, 2021). https://paysonchronicle.blogspot.com/2021/10/beautiful-utah-wonderfully-weird-world.html
Carey, Trevor. 2018. The Conservation of the Kanab Ambersnail. University of California-Davis Center for Watershed Sciences. https://cwseducation.ucdavis.edu/class/116/conservation-kanab-ambersnail
List of mollusks of Utah facts for kids. https://kids.kiddle.co/List_of_mollusks_of_Utah
National Park Service. Western Pearlshell. https://www.nps.gov/articles/000/western-pearlshell.htm
Palacios, Patsy, Chris Luecke and Justin Robinson. 2007. Paleo-biology and paleo-hydrology of the Bear Lake Basin, Utah. https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1592&context=nrei
Utah Division of Wildlife Resources. Collection, importation, and possession of fish, mollusks, and crustaceans in Utah. https://wildlife.utah.gov/cip
Wagner, Eric, and Christy Bills. 2024. Three gastropod species reported in Utah for the first time. https://scholarsarchive.byu.edu/wnan/vol84/iss1/12/
