The beagle patrolling Toronto Pearson International Airport was prowling for the subtle scents of contraband when an unexpected odor tickled its olfactory receptors. The source was the luggage of a Canadian man who had just returned from Russia.

The dog knew what to do next and plonked down next to the traveler—sending a signal to Canada Border Services Agency personnel that something was amiss.

Officials peered inside the man’s bags and found hundreds of containers filled with slimy, writhing objects—5,000 live leeches. It was October 17, 2018, and the trusty beagle had helped authorities snag Canada’s first known leech “smuggler.” (Authorities are calling him an alleged illegal leech importer, rather than a smuggler, because he wasn’t necessarily purposefully hiding the contraband.)

The incident, revealed here for the first time, is not yet part of the public record. The man was charged with illegally importing an internationally regulated species without the required permits, says André Lupert, manager of intelligence for the Wildlife Enforcement Directorate at Environment and Climate Change Canada, Ontario Region. According to Lupert, the man is awaiting a court hearing next month in the greater Toronto area. To protect his privacy and because the investigation is ongoing, the Canada Border Services Agency said they can’t share his name or other details of the incident—including the dog’s name or even the dog’s sex.

Leeches are parasitic worms found on every continent except Antarctica. Many live on blood (some need just one meal a year), earning them the disgust of unwitting victims but proving useful in medicine. The seized leeches consisted of two species—the southern medicinal leech and the European medicinal leech—preferred for use in hospitals, plastic surgery centers, and burn units around the world. The leeches consume pooled blood and improve circulation to injured tissue by secreting natural anticoagulants. They can sell for about $10 each.

The man claimed that the leeches in his possession were for personal use and that their waste water would enrich his orchids, Lupert says.

To Lupert, that seems shaky. “This sort of leech quantity would suggest it was for commercialization,” he says, adding that the man could have been trying to find buyers for leech uses such as treating frostbite and helping with recovery from face lifts. Some people want leeches for naturopathic home use, believing that they relieve pain or can cleanse the body of “bad” blood. Without prescribed antibiotics, however, any such use carries risk of infections.

Leeches as medical helpers go back to ancient Egypt. In early 19th-century Europe, overuse of them for bloodletting led to some of the earliest wildlife conservation protections, according to research by Roy Sawyer, leech aficionado and founder of the Medical Leech Museum, in Charleston, South Carolina. The little creatures were so widely used that local sources in western Europe largely dried up, Sawyer noted. Their dearth inspired William Wordsworth’s poem “The Leech Gatherer” in 1802.

Under the treaty that governs international wildlife trade—the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)—shipments of certain threatened species would be illegal without the required export-import permits. CITES regulates a variety of animals and plants—including the two leech species seized by authorities—to ensure that commercial demand doesn’t wipe them out. With the proper paperwork, medicinal leeches can be shipped legally from one country to another. Canada, for example, gets much of its supply from the United States according to Lupert. For its part, the U.S. approved leeches as medical “devices” in 2004.

View Images Leeches were in such high demand in Europe during the 1800s that they became endangered, eliciting numerous export bans that are considered some of the earliest wildlife conservation protections. Today, global sales of the two main medicinal leeches are regulated. Photograph by Paul Van Hoof, Minden Pictures

Of the hundreds of species of leeches, only a few have a taste for human blood and will hungrily latch onto a bare leg or arm, explains Mark Siddall, a leech expert and the curator of invertebrates at the American Museum of Natural History, in New York City. The species the Canadian was caught with are hearty biters, Siddall says.

Unwanted leeches

When Canadian officials seized 5,000 leeches, they were immediately confronted with a problem: what to do with them? They didn’t want to kill the threatened animals—especially while the case remained under investigation. “Ultimately it’s up to the judge if he wants to view the leeches in person because they’re viewed as evidence,” Lupert says. Nor did the authorities want to be saddled with them long-term. These species aren’t endemic to Canada, so they shouldn’t be released into the wild, Lupert says.

An unfortunate incident hastened authorities’ desire to be rid of the leeches. “We were learning on the fly how to house these things,” says Lupert, who is also the acting regional director for wildlife enforcement in Ontario. “These are pretty active creatures. We changed the water regularly, and when the officers came in one morning, they found that 20 had escaped,” he recalls with a chuckle. Luckily, the leeches were quickly recaptured and returned to their containers.

Government officials started making phone calls to find alternative housing for the leeches. The responses were underwhelming. “Think about putting 20 of these in a mason jar—think of the room that would be required for all of these when you have 5,000,” Lupert says. “It’s not just a matter of giving them away and saying here you go.” (Related: What happens to smuggled animals after they're seized?)

Medical facilities contacted weren’t enthusiastic about taking in so many—Canada as a whole typically acquires between 500 and 1,000 medical legal leeches a year, Lupert notes, so 5,000 is a big ask.

He says that only the Royal Ontario Museum, in Toronto, agreed to take some—just 50—which still left law enforcement with some 4,950 leeches in a room with other confiscated live animals, including turtles and tortoises. (The museum also identified the two species of leech in the haul, Lupert says.)

Widening their field of inquiry, the Canadians eventually found a home for a thousand at the American Museum of Natural History, thanks to Mark Siddall. But there was a catch: Canada and the U.S. would have to draw up formal export and import paperwork, further delaying the cross-border leech airlift.

Two months after the bloodsuckers were confiscated, Siddall’s lab received a consignment of 1,000 leeches. “With 25 years of leech biology and behavior under my belt, I’ve got the experience—and the grad students—to help out,” he says of the leech caretaking demands. “You need to change the water, know what they look like when they are not doing well, if they need to be fed, and know when to start separating sick ones from healthy ones.”

This isn’t Siddall’s first time taking in leeches. “Without going into too many details, this has happened before,” he says. Pressed for more information about the cloak-and-dagger nature of leech smuggling, he declined to comment on the circumstances of prior incidents, referring National Geographic to the U.S. Fish and Wildlife Service, the agency responsible for overseeing wildlife imports and exports.

Spokesperson Christina Meister said the service doesn’t have readily available data on leech smuggling. Nor, she said, do the staff know of examples of closed cases—to find out more, it would be necessary to file a Freedom of Information Act request. On December 17, 2018, National Geographic filed a FOIA request for records of leech imports from 2007 to present, which would include seizures.

The New York-based nonprofit EcoHealth Alliance keeps a database of wildlife trade, called WILDd, which draws from official U.S. government data on shipments of wildlife and wildlife products, among other sources. According to EcoHealth Alliance, 10 leech shipments were refused entry to the U.S. between 2000 and 2014—meaning officials either seized them or sent them back to their country of origin. EcoHealth’s program and evaluation manager Allison White found those refusals collectively amounted to at least several thousand leeches. The specifics of each incident remain unknown.

As for Canada’s big leech seizure, a judge will hear the man’s case on February 15. Meanwhile, officials are still endeavoring to find a home for the remaining 3,950 leeches.

“Want some pets?” Lupert asks.

Editor's note: This story was originally published on January 25, 2019. By February 10, Environment and Climate Change Canada said that because of the awareness created by this article, a number of academic institutions reached out to authorities offering the leeches homes. They are now all spoken for, except for a small number that had already perished.