A rat king, or “roi de rats” in French, is a collection of rats whose tails are intertwined and bound together.
It typically occurs when young rats, sleeping together in close quarters, get their tails entangled, forming a knot.
The tied tails are prone to being encrusted by dirt, or stuck together by substances such as sap, sebum, blood, food, faeces or urine.
When the rats wake up and attempt to scurry away from each other, the knot then tightens, trapping them.
Unable to feed themselves, the rats eventually die.
A number of examples have been documented throughout history – mostly from Europe – with the earliest report coming from the 16th century.
The largest rat king on record was found in May 1828, in a chimney in the German town of Buchheim, Altenburg.
It consisted of 32 individual rats.
The discovery was made when a miller named Steinbrück had the walls of his chimney torn down, whereupon he found a mummified rat king under the rubble.
The rats were hairless and blackened with soot, though their claws remained sharp.
Steinbrück gave the record-breaking rat king to the Altenburg Natural Research Society, who put it in a glass case and presented it to the public.
In 1908, it was moved into the newly-built Mauritianum Natural History Museum, where it remains on display today.
The Altenburg rat king was comprised of black rats (Rattus rattus) aka house rats or roof rats.
In fact, most surviving specimens of rat kings are formed from black rats.
The reason for this, according to some theories, is that black rats – known to be particularly skilled climbers – have prehensile tails, like monkeys, which instinctively make a grasping reflex when they touch something.
When confined into a small space, such as between the upper floorboards of a house, the rats’ tails clutch at each other and become intertwined.
As the rats continue to crawl over each other before eventually falling asleep, the ensuing knot becomes irreversibly hardened by the aforementioned cocktail of sticky substances and other materials such as clay, hay and dirt.
Credence is lent to this theory by the fact that most rat kings have been found during winter, in confined spaces.
More recent examples of rat kings include one found in New Zealand in 1930 – now displayed in Dunedin’s Otago Museum – comprised of eight immature black rats entangled by horse hair.
Their tails showed signs of broken vertebrae, suggesting they had tried to forcefully free themselves of their predicament.
A rat king discovered in 1963 by a farmer in the Netherlands consisted of seven rats, according to a report published by cryptozoologist M. Schneider. X-ray images taken after the rats were killed showed callus formations at the fractures of their tails, suggesting they had survived for an extended period of time as a rat king.
In 2005, a 16-strong rat king was found by an Estonian farmer. Some of the rats were dead, though many were still alive. Ultimately, they were all euthanized as they could not be freed. 13 were preserved and they are now part of the collection at the University of Tartu Natural History Museum.
The museum’s collection also contains the world’s most recently discovered rat king, found in Estonia in October 2021, as seen in the video below. It consisted of 13 live rats. Again, they were humanely euthanized because they could not be freed.
Although some zoologists remain sceptical about the existence of naturally-occurring rat kings, instead choosing to believe that past cases are man-made hoaxes, there is now also undeniable proof of the existence of squirrel kings, proving the phenomenon occurs amongst other rodents too.
Thus, as much as we wish it weren’t true, rat kings are a real thing, and this record could still be broken…
