That stopped me right in my tracks, piqued my curiosity, that was not what I was expecting to come across. Gerbils responsible for the plague. I immediately had to know more. So I turned to Google for some news articles on the subject.
As you can see from those few results in the above image, it turns out it's not so cut and dry, there's a lot of debate about whether or not it was actually the gerbils or whether it was indeed the rats like it has historically been attributed. The original study that inspired all this gerbil related sensationalism is a report by titled Climate-driven introduction of the Black Death and successive plague reintroductions into Europe. The article from the Skeptics Guide, which was the top result in the Google search was actually very interesting and does a really good job of explaining how the media took the original report out of context for the sake of headlines. Alison Atkin, whose article Avoid Killer Gerbil Headlines Like a Cliche was linked in the Skeptics Guide article as being a good explanation of the chain of logic in the original study, commented on the article with a link to another of her articles, Blame The Gerbils? Blame The Journalists! which explores how the media blew it so out of proportion.
This is just another standard example of not taking everything the media tells you at face value, it's always a good idea to do some digging into the headlines.