This story is an excerpt from the book Gory Details: Adventures From the Dark Side of Science by Erika Engelhaupt.
On August 20, 2007, a 12-year-old girl spotted a lone blue-and-white running shoe—a men’s size 12—on a beach of British Columbia’s Jedediah Island. She looked inside, and found a sock. She looked inside the sock, and found a foot.
Six days later on nearby Gabriola Island, a Vancouver couple enjoying a seaside hike came across a black-and-white Reebok. Inside it was another decomposing foot. It, too, was a men’s size 12. The two feet clearly didn’t belong to the same person; not only were the shoes themselves different, but they both contained right feet.
Police were stunned. “Two being found in such a short period of time is quite suspicious,” Garry Cox of the Royal Canadian Mounted Police told the Vancouver Sun. “Finding one foot is like a million to one odds, but to find two is crazy. I’ve heard of dancers with two left feet, but come on.”
The next year, five more feet appeared on nearby Canadian beaches. The discoveries ratcheted up the public’s fears, and media speculation soared. Was a serial killer on the loose? Did he have something against feet?
Over the course of the next 12 years, a total of 15 feet washed ashore in the area around Vancouver Island, a network of waterways called the Salish Sea. Six more turned up in Puget Sound, which lies across the U.S. border at the southern end of the sea. With the exception of one foot wearing an old hiking boot, all of them were encased in sneakers. The sneaker-clad feet became famous, even garnering their own Wikipedia page. And with fame came hoaxes: pranksters stuffed shoes with chicken bones or skeletonized dog paws and scattered them along Canadian shorelines.
Tipsters called police with all manner of theories about the origins of the feet. “We get some very interesting tips that come in about serial killers, or containers full of migrants that are sitting at the bottom of the ocean. Aliens—had that one as well,” says Laura Yazedjian, a forensic anthropologist who works as a human identification specialist for the British Columbia Coroners Service. “And occasionally a psychic. Actually, pretty much every single time, a psychic will call and offer to help.”
But this type of mystery, it turns out, requires scientific, rather than criminal investigation (or psychics). In fact, science can answer all of the obvious questions—for example, why are feet, and not entire bodies, washing ashore? And why are they showing up on this particular stretch of British Columbia’s shores? But the research that has addressed these questions is anything but obvious. To understand how the feet got where they did, we have to follow some unexpected lines of inquiry, involving everything from the science of sinking to the decomposition of pigs and spreading oil spills.
To sink or swim
To begin, we must understand what happens to a dead body once it’s in the water. So let’s follow the adventures of a seafaring cadaver.
Once in the water, a cadaver’s first move will be either to float or to sink. This is a surprisingly crucial step, as it will help determine what happens next. A floating object will be carried with the winds and by surface currents, and might soon wash ashore. A sinker, on the other hand, might remain in place, or be tugged in a different direction by deeper currents. What’s more, a floating body, exposed to air, will decompose differently from one that sinks, with ramifications for the fate of its feet.
One might assume that a drowned person will sink because their lungs are full of water, and that a cadaver’s air-filled lungs would otherwise act as a flotation device. But the reality is not so simple. Using data collected in 1942, E.R. Donoghue of the Armed Forces Institute of Pathology set out to settle the matter in a 1977 article titled “Human Body Buoyancy: A Study of 98 Men.” The 98 men in question were “healthy U.S. Navy men in the 20-to-40-year age group.” Each was suspended underwater and weighed both with his lungs full of air, and after expelling as much air as possible. It’s no easy task to wait to be weighed underwater with no air in your lungs—but again, these were Navy men.
With their lungs fully inflated with air, all the men floated. But once they had emptied their lungs (as would be the case with a dead body) most of the men sank in freshwater; only 7 percent floated. In seawater, though, people are more buoyant: 69 percent of the Navy men would float if they were dead and naked in the ocean, Donoghue estimated. But it was a close call; just a little added weight, such as heavy clothing or water in the lungs, could cause a body to sink. In the end, the data suggest, cadavers are overall more likely to sink than to float, and people who drown are the most likely to sink.
What’s more, once a body sinks, it tends to go straight to the bottom. Sometimes, an underwater cadaver will eventually bloat, just like a body on land, causing it to bob to the surface. But that doesn’t always happen, says Yazedjian, the investigator from the Coroners Service. In a deep lake or ocean, it may never come back up. Not only does the cold inhibit decay in deep waters, but the greater water pressure there also prevents any gases from expanding and causing bodies to float. Instead, other microbial processes take over and convert a sunken body’s tissues to adipocere, “this kind of waxy, soaplike tissue,” she says. Adipocere can persist for years, even centuries, in a low-oxygen environment.
And that’s exactly what Yazedjian saw on the feet she examined from the Salish Sea. They were covered in adipocere, suggesting that the cadavers sank, and remained underwater as they decomposed. That could explain where the remainders of the bodies were: They sank and stayed sunken.
But why didn’t the feet stay down with the bodies?
Feet set sail
To understand how the feet set sail sans bodies, we need to know how a human body might decompose underwater, and whether its feet are prone to pop off and float away. Scientists study the process of human cadaver decomposition at several U.S. forensic research sites, but these are all on land; none had ventured to drop a body into the ocean. (Find out how cadavers help advance all kinds of scientific research.)
But our investigation is not dead in the water. In the summer of 2007, forensic scientist Gail Anderson of Simon Fraser University was conducting a study for the Canadian Police Research Centre to understand how quickly a homicide victim would decompose in the ocean. Because ethics rules preclude using a human body, she used a dead pig instead. Pigs have often been used in forensic research as stand-ins for a human body; they are roughly comparable in size and are quite similar biologically.
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- A new guide for communicating plant science – EurekAlert
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- Dublin school opens much-anticipated new science, engineering building – The Mercury News
- Wearable sensors that detect gas leaks – EurekAlert
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