Gerbils: Not As Innocent As You May Think

We are no fans of rats. That’s just one reason we think Alberta, Canada is the Promised Land because of its enlightened “no rats” policy. Even so, we can’t stand by and allow them to take the blame for all of mankind’s problems. For the past 800 years, black rats have taken the fall for the bubonic plague, which swept through Europe like a nightmarish game of tag. Hold on to your history books, because a new study suggests we’ve been pointing our pitchforks at the wrong rodent. Gerbils, the supposedly adorable pets you might have in your home right now may have been the culprit all along.

Plot Twist: Gerbils Are Not As Innocent as They Want You To Think

Yes, gerbils. Yes, those cute, innocent, would-never-hurt-a-flea (except they totally did) gerbils that may have been the real culprits behind the Black Death.

We were just as floored as you. A paper published in the Proceedings of the National Academy of Sciences by researchers from the University of Oslo has turned our understanding of medieval epidemiology on its tiny, whiskered head. They went full CSI: Climate Edition, examining 14th-century weather data and realized something didn’t add up. It turns out, rats aren’t fans of certain climate conditions. To paraphrase the lead author, Nils Christian Stenseth, rats like it warm and dry—not exactly the weather report for plague-ridden Europe. “For this, you would need warm summers, with not too much precipitation,” he said. One tiny problem: that’s not the weather 14th century Europeans experienced.

Gerbils: The Unexpected Supervillains

It turns out there was a connection between the climate in Asia and plague outbreaks in Europe, spanning from the late 1300s all the way into the 1800s—a time historians like to call “that awful second plague pandemic.” So, the Oslo team dug deep, analyzing 7,711 historical plague outbreaks (a number only epidemiologists and people who count beans could love) and compared them to tree-ring climate data. Their findings? European plague outbreaks almost always followed a warm summer in central Asia, right after a rainy spring. That’s terrible news for black rats but prime gerbil vacation weather.

Here’s where things get interesting. The researchers now suspect that after those balmy summers, our friends the gerbils, along with their flea companions carrying the Yersinia pestis bacteria, hitched a ride to Europe via the Silk Road. A few years later, Europe was hosting a plague party, and the guest list included fear, death, and a lot of confused rats.

Sorry, Rats—We Owe You an Apology

This discovery doesn’t just vindicate black rats for the original Black Death outbreak; it clears their name for the entire second plague pandemic. They have been taking the heat for the deaths of over 100 million people across Europe for centuries. Talk about a PR nightmare. Sarah Kaplan from The Washington Post put it like this: “[The findings] also explain why the disease popped up intermittently century after century, rather than hanging around as long as rats were there to carry it.” Poor rats—turns out, they weren’t even in the game most of the time.

And Now for a New Plague Theory (Because Why Not Kick History Teachers While They Are Down?)

But wait, there’s more! This isn’t the only new theory bouncing around. Recently, some scientists proposed that the plague may have been airborne, spreading through coughs and sneezes rather than flea bites. It’s like a plot twist nobody saw coming.

The team is now setting their sights on ancient European skeletons. If they can find genetic changes in the plague bacteria over time, it would support their theory that fresh waves of plague were brought over by newly arrived gerbils, rather than rats who were just trying to live their best medieval lives.

“If we’re right, we’ll have to rewrite that part of history,” Stenseth said. Now, maybe, just maybe, after eight centuries of misplaced blame, we can finally clear black rats of their role in one of the worst epidemiological disasters in history. Honestly, after all this, we kind of owe them an apology. A big one.

We’re still not inviting them over for coffee, though. We don’t care how misplaced the blame has been.

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