Emily Kwong

And we have a pretty good understanding of what caused the Black Death.

And the reason, Elsa, that scholars think so many rats were hitching a ride to Italy that year...

had to do with food.

Hannah Barker, a historian at Arizona State University, discovered there was a reopening of the grain trade between the Mongol Empire and Genoa in 1347.

Seven centuries ago.

Totally.

It's really interesting.

So Martin and his colleague Ulf Buntgen looked at ancient tree ring samples, which found bad growth conditions.

In the years leading up to the plague, they looked at ice cores containing unusually high deposits of sulfate aerosols, which suggests volcano.

And they published their findings in the journal Communications Earth and Environment.

Yep.

Beautifully summarized.

Now, this is just a hypothesis, of course, but it suggests that one of the biggest pandemics in human history could have been connected to the climate.

Yeah.

Okay.

So it turns out worker ants are paying close attention to the pupae.

That's the stage when juvenile ants are still in their little cocoons.

And it appears that when pupae have an infection like a fungus, they send out a chemical message calling for those worker ants to destroy them.

One of the study authors, Erica Dawson, explained the process to us.

She says first, the worker ants peel off the cocoon.