History ratted out the wrong rodent. For centuries, the black rat has been blamed for the bubonic plague pandemic that ravaged medieval Europe and killed millions of people. But climate researchers are now pointing the finger at Asian giant gerbils, whose populations rose and fell in a weather-related pattern matching the outbreaks. Asian gerbils are still carriers of the plague-causing Yersinia pestis bacteria. Not to worry, though, your furry pet is fine — it’s as innocent as the rat.