Plague lives in some rodent species. They act as a reservoir for the plague bacterium, and they don't seem to get ill from it. But then what can happen as those rodent species come in contact with other s that are living in our cities? And so either the rodens themselves, or the fleas jump off those rodents and get on to the other rodens. Those rodent species we call, are susceptible, so they do fall ill eventually. So you can get what are called rat falls, or mass dioffs, of rats in cities that contract plague. Then what do they look to bite? Well, they bite us, because we're the only other thing