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Meet Sandy the Snail

This “left-handed” snail is one of a kind

This little lefty snail is named after Sanford “Sandy” Koufax, the famous L.A. Dodgers left-handed pitcher from the 50s and 60s.


Most snails are “right-handed.” Well, they don’t have hands, so really, most snails are “right-shelled.” Indeed, if you look down at a snail, the shell coil is on one side, and for the majority of snail species, it’s on the right.

But not this snail. Sandy, a common garden snail (Cornu aspersum), has a left-coiling shell. The scientific term for this is sinistral. Sandy is a sinistral snail, as opposed to nearly all other garden snails, which are dextral, or “right-handed.”

How did this happen? Just like handedness in humans, the exact cause is not completely understood. No one has worked out which exact genes cause left-handedness (or left-shelledness, as it were), so it might be caused by a combination of genes and possibly environmental influences too.

Named after famous L.A. Dodgers left-handed pitcher Sanford Koufax, Sandy was discovered by Alex Bairstow, a high school senior and nature enthusiast in Escondido, CA. With a keen eye for snails, he knew Sandy was different as soon as he saw it.

“I had gotten to school early, so I decided to walk around the campus to look for snails, bugs, and lizards to add to our school's biodiversity project on iNaturalist,” said Bairstow. “I found Sandy when I noticed a snail that looked different out of the corner of my eye. I realized it was sinistral when I bent down to get a closer look, and was quite astonished to say the least!”

Bairstow snapped a photo and uploaded it to SLIME (Snails and Slugs Living in Metropolitan Environments), an NHMLA citizen science project on iNaturalist — a platform where anyone can post photos of plants, animals, and fungi that scientists can use for research.

He later brought Sandy to the Museum so Malacology Assistant Curator Jann Vendetti and Collections Manager Lindsey Groves could take a closer look at this “left-handed” oddity and add it to the Malacology Collections — the first sinistral snail specimen of an otherwise dextral species.

“This is so rare, we don’t even know how rare it is,” explained Vendetti.

“I’ve never seen a live one before!” said Groves. “When I first saw it, I thought, ‘Oh, another garden snail.’ But then I looked closer and was really excited.”

For Sandy, being different from its fellow snails is actually a real disadvantage. Being the lone lefty among a species of righty snails means you can’t reproduce, as it’s not just the shell coil that’s on the right — garden snails’ genitalia are on the right side, too.

Most snails are hermaphrodites, which means they have both female and male genitalia. In order to mate, they need to line up in a specific way, allowing their reproductive organs to match so they can fertilize one-another.

a photo of three snail shells in a container
These Japanese sinistral snails were part of the J.M. Lane collection donated to the museum in the early 1930’s.

This means it’s nearly impossible for Sandy to reproduce, since its genitalia are on the opposite side. It’s a little like trying to shake hands with someone if you use your right hand, and they use their left. It doesn’t fit together into a successful handshake. It’s just a clumsy touching of hands.

There are species of snails that are all lefties, though, such as Euhadra quasita, a Japanese land snail. These entirely sinistral species may have evolved when two left-handed snails of an otherwise right-handed population met, reproduced, and started a species all their own, passing down their “left-handedness” to their offspring.

Will Sandy the Sinistral Snail find a mate in its lifetime? Garden snails live for about six years, and Sandy’s large shell suggests it’s solidly middle-aged (or perhaps just really well-fed). Only time (and citizen science!) will tell if another left-handed garden snail will cross its slimy path. Keep your fingers crossed for this misfit mollusc.


Seen a snail lately? Submit snail and slug observations to the SLIME project on iNaturalist!


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