The flea (Photo: George Poinar, Jr.)

A flea that has been preserved for 20 million years in an amber mine in the Dominican Republic had some company all that time: tiny bacteria that look an awful lot like the Black Death.

When George Poinar, Jr., an entomology researcher at Oregon State University, examined the flea, he noticed that the it had a bump on its rear end. Fleas that carry the plague tend to have this bump due to the bacteria that collect there and on a flea’s proboscis. When Poinar looked the amber mine flea’s proboscis, he found bacteria there, too. They had the distinct shape of Yersinia pestis, which caused the Black Death.

These bacteria, then, may have been a very distant ancestor of that disease, which means Yersinia pestis has a much longer history than we previously knew about. The Black Death version of the bacteria evolved about 20,000 years ago, which was around the time that fleas started spreading plagues to creatures like rats and humans. 

But this discovery shows, as Poinar says, that Yersinia pestis predates the human race. These tiny organisms really are good at surviving no matter what the planet throws at them. Don’t be surprised if viruses and bacteria inherit the Earth, and probably Mars, too.

Bonus finds: Bronze age saunaAntikythera shipwreck knick-knacks

Every day, we highlight one newly lost or found object, curiosity or wonder. Discover something unusual or amazing? Tell us about it! Send your finds to