The Love Song of Jeremy the Left-Coiled Snail

How researchers found a mate for a rare mollusc

Right-coiled snails at a park in Germany (Kai Pfaffenbach / Reuters)

One night in early October, Angus Davison got an email about a snail.

When one is a biologist who studies molluscs, that's not out of the ordinary—but this time, the snail was something special. A retired scientist from the Natural History Museum in London spotted the creature near a compost heap in the neighborhood of Rayne's Park, and was struck by something very peculiar: The snail's shell coiled left, rather than right. That's very rare—it's probably, Davison estimates, 1 in 100,000 garden snails that go in that direction. And so, when a colleague at the museum emailed Davison and asked, “Would you like it? Otherwise I'll put him in the freezer,” Davison was quick to rescue the snail from a frozen fate.

Once the snail had been mailed to University of Nottingham, where Davison is a professor, the question became, “Well, what can we do with this snail?” Davison says. The clear answer, from a biologist's perspective, was to mate it. That's because understanding what it is about Jeremy, as the snail soon came to be called, that makes its shell go the opposite way will require seeing whether the trait can be passed on. And if it can, Jeremy's genes may help reveal how it is that creatures of all kinds, from frogs to snails to humans, develop left and right sides. Davison and colleagues published a paper about a gene behind sidedness in March that Ed Yong covered for The Atlantic—it's a particular fascination of the lab.

Jeremy, happily, is a hermaphrodite. As with many snails, “he” can have male or female reproductive organs, depending on the situation. But right-turning snails' genitalia is on the wrong side of their bodies to be able to mate with Jeremy. And the researchers knew of no other lefties. So Davison and colleagues took a somewhat unusual approach: They put out a call—a personal ad, if you will—to the public:

One left-turning snail wanted for romantic entanglement; desire for children a must.

Almost immediately after Davison appeared on Radio 4 on October 21 talking about Jeremy's plight, listeners began to send in photos of snails. “But a lot of people confuse left and right,” Davison notes, when it comes to snails. (A left-turning shell will coil counter-clockwise if you are looking at the snail right-side up; right-turning is clockwise.) In early November, however, he got an email from Jade Sanchez Melton, a snail enthusiast in Ipswich who keeps more than 300 as pets. She had Lefty, a snail she'd found a year ago and knew immediately was unusual. And then, Miguel Àngel Salom, a snail farmer and restaurant owner in Majorca, contacted Davison to say he'd found one among his flock.

Right now, Jeremy is in Ipswich with Lefty, where the pair have just concluded their third night together. “They have not mated yet as far as we can tell,” says Davison, “but there has been interest. There has been flirting.” Snail courtship involves first touching the other party repeatedly, then, ultimately, stabbing them with little calcium crystals known as love darts. The crystals carry a hormone, and the thought is that this hormone may convince one snail to accept the other's sperm and act as the female, says Davison. Once that's been decided, the snails touch genitalia to complete the transfer, and some time later, one lays the eggs.

Whether the courtship will be successful remains to be seen. “I know last week Jeremy was being kept with another snail, a righty snail, just in case they could mate. They tried to mate and they didn't succeed,” says Davison. “So he might be a little bit spent at the moment.”

But Davison is hopeful. “I would imagine,” he says, “that in a couple of weeks we can get evidence of a mating—eggs.”