TikTok doctor explains why sneakers filled with human feet keep washing up on beaches in the Pacific Northwest

• Since 2007, at least 20 human feet in sneakers have washed up on the coastline of the Pacific Northwest.
• Conspiracy theories about the Salish Sea feet discoveries previously blamed a serial killer with a foot fetish.
• But, as a British doctor explained to his 4m TikTok followers, it's most likely the result of modern sneaker designs.

A video of a doctor unraveling the mystery of why sneakers containing severed feet keep appearing on the beaches of the Pacific Northwest has gone viral on TikTok.

At least 20 human feet have washed up on the coastline of the Salish Sea, which stretches from Canada's British Columbia to the US State of Washington, since August 2007, the Mirror reported.

The most recent example took place on New Year's Day in 2019 when beachgoers on Jetty Island in Everett, Washington, found a foot in a boot.

While conspiracy theorists have suggested that the grisly discoveries could have been the victims of a serial killer with a foot fetish or the mafia disposing of bodies, Dr. Karan Raj told his four million TikTok followers that there is a simpler explanation.

In a video now watched over 650,000 times, Raj explained that the foot discoveries are down to the human anatomy and, in part, to footwear designs.

"When a human corpse falls to the ocean floor, it's quickly set upon by scavengers," Raj said in the video. "These scavengers are lazy feeders and prefer to tackle the softer parts of the body than the tough, grisly bits."

Raj explained how some of the softest parts of the human body are the tissues and ligaments around the ankles. "When scavengers chow down on this, the foot will detach pretty quickly from the rest of the body," the doctor continued.

According to entomologist Gail Anderson, human feet and hands often detach from the rest of the body when in water, but they rarely float.

The buoyancy of modern sneakers, Raj said, is what makes them float and, eventually, wash up on the shores of the Pacific Northwest.

Sneakers made in the last decade often have gas-filled pockets in their soles makes them particularly unsinkable, according to National Geographic.

As to why the feet specifically appear along the Salish Sea's shores, oceanography professor Parker MacCready told National Geographic that the area has the "perfect storm" for shoes washing up.

The fact that it's a large and complex body of inland water acts as a trap and ensures that water-bound items stay in the Salish Sea, MacCready said. Also, he continued, the prevailing winds are westerly and tend to bring things in from the ocean rather than pushing them out.

According to The Guardian, the British Columbia Coroners Service has ruled out foul play in all investigations into Canadian human foot discoveries. None of the feet showed signs of trauma and all of the individuals appear to have died by suicide or been killed in an accident, a coroner said.