The History of Rats

Over the history of civilization, rats traveled wherever humans traveled. That is, if you count "civilization" as the time beginning when we started growing our own grains. rats love those things. But furthermore, rats traveled to places where people didn't migrate as much, so they managed to spread fleas and disease to far-flung populations of people.

But the misery that rats spread among humans wasn't because they are evil. They've just become dependent on humans to provide their food. This TED-Ed lesson from Max G. Levy tells us the good things about rats, too. (via Laughing Squid)