If you are eating right now, you might want to save this article for later. Despite the cute picture and the cartoonish-sounding title, rat kings are not adorable pet rats in fancy dress. On the contrary, what we know of rat kings is the stuff of nightmares.
A rat king is group of rats whose tails have become entwined, and the first known sighting of one was in Germany in 1564. It was once thought that rats would twine their tails together on purpose to stay warm in cold environments and to protect themselves. People believed that these rodents would operate as one animal, moving about to find food and water. Rats have undoubtedly been found in such a state, and you can even view some preserved specimens in a few museums around the world. Some particularly gruesome specimens contain 30 rats or more. The idea that these animals joined together by choice or for survival is where myth enters the picture.

Here’s where things get really gross. Rather than voluntarily tying their tails together, rat kings are formed when the animals end up stuck in cramped quarters for a period of time. They produce a greasy sebum, or body oil, that helps keep their skin hydrated and assists them in moving through tight spaces by greasing up surfaces. This substance can cause the rats to get bound together. In addition, urine and feces in large quantities could cause them to get glued together near the tail area. There was even a recorded case of a squirrel king in 2013, where some squirrels got matted together due to tree sap.
The animals do not benefit from this condition, either. In fact, if a pack of rats became joined in this way, they would likely die very quickly and in severe pain. Most rodents would simply chew their tails off to escape.
So, if rat king formation is not voluntary, and the animals could usually escape from the predicament, why are there so many specimens in museums? Some scholars believe that many are fakes, and that the tails of the animals were stuck together after they were killed. Alternatively, some of them could have been made up of rats too tangled and matted to escape and subsequently died in their entwined state. In any case, the poor animals certainly did not come together in order to form some super-survival rat-beast.
Until the formation of a rat king can be replicated in a lab, we probably won’t know everything about them. Oddly enough, there are researchers who want to study the phenomenon, but funding for such a study has not been forthcoming.
Because you were warned that this would get disgusting, here is a picture of a preserved rat king. Sweet dreams!
