Are 'Rat Kings' — Rats Fused Together by Their Tails — Actually Real?
A "rat king" is a knot of rats fused together by their tails, moving — or unable to move — as one mass. It reads like a monster invented to scare children, the kind of thing that surely turns out to be a hoax the moment anyone looks closely. It doesn't. Real specimens sit in real natural-history museums with real accession numbers, and the closest thing to an expert on the subject was still personally examining a fresh one as recently as 2021. What isn't settled is how, exactly, it happens — and whether every specimen in a museum case is what its label says it is.
The claim
Rat kings — multiple live rats whose tails have become permanently entangled into a single mass — are a genuine, if rare, biological phenomenon, documented by preserved museum specimens and at least one peer-reviewed academic survey, not solely a folkloric invention or a fabricated curiosity.
Source trail
The image is old European folklore first: a knot of rats as an omen, tied to plague years, going
back to at least the 16th century by most accounts. The modern scientific anchor is a single 2007
paper, "Rat Kings in Estonia," by zoologist Andrei Miljutin, published in Proceedings of the
Estonian Academy of Sciences, Biology and Ecology (56(1): 77–81) — the paper every serious
source on the topic, including Wikipedia and National Geographic, traces back to for its actual
count of how many documented cases exist. We could not read Miljutin's paper itself: the publisher's
own PDF (kirj.ee) returned unreadable binary content to our fetcher rather than
extractable text, and a ResearchGate mirror of it returned an access-denied error. Everything below
attributed to the paper comes from National Geographic's reporting on it, not from us reading it
directly — stated here so that distinction isn't lost. Separately, Miljutin himself remained an
active, on-the-record source fourteen years later: Estonian public broadcaster ERR interviewed him
directly in October 2021 about a fresh live case, which we did read as ERR published it.
What's confirmed
- Multiple named, dated, museum-housed specimens exist, and we independently checked three of them. The largest documented rat king — 32 individual rats — was found in a chimney in Buchheim, near Altenburg, Germany, in May 1828 by a miller named Steinbrück, and has been held by the Mauritianum Natural History Museum since 1908; Guinness World Records, fetched directly (checked 2026-08-22), lists it as the official record holder and states the rats were "hairless and blackened with soot" from the chimney but their claws remained sharp. A second specimen — eight immature ship rats (Rattus rattus) tangled by horsehair from their own nest — fell from the rafters of a Dunedin, New Zealand shipping shed in the 1930s and is preserved today in the Otago Museum's "Animal Attic," per the Otago Daily Times, fetched directly (checked 2026-08-22), which also carries a named eyewitness account (shipping clerk Walter Lawry) of the parent rat fighting off workers with enough ferocity that one had to be driven back with a pitchfork.
- A rat king was found alive as recently as October 2021, and the scientist who wrote the 2007 academic survey personally examined it. ERR, Estonia's public broadcaster, fetched directly (checked 2026-08-22), reports thirteen rats found tangled together in a chicken coop in Põlva County; they were humanely euthanized and are now held at the University of Tartu Natural History Museum. Andrei Miljutin — the same author as the 2007 paper, now a museum curator — is quoted directly explaining the mechanism as he understands it: "The rats start to move when they wake up and move in different directions, they end up tying their tails together and can no longer get free. The more they struggle and pull, the tighter the knot gets."
- An independent expert, shown the evidence, confirmed the phenomenon is real rather than dismissing it. National Geographic, fetched directly (checked 2026-08-22), quotes Bobby Corrigan — described as an urban rodentologist with more than 30 years' experience and a former Purdue University instructor — after he reviewed Miljutin's findings: "For sure, it is real, but it is rare, or at least rare to us humans. Maybe not to the long-tailed rats of the world."
- Per National Geographic's account of the 2007 paper, nearly every documented case involves one species, and the tails are bound by material, not tied in a true knot. With one exception from Java, every case Miljutin counted involved the black rat, Rattus rattus, concentrated in Germany, France, Poland, the Netherlands and Belgium. National Geographic states plainly that "rat tails cannot be tied into a knot" — the entanglement instead comes from a sticky or stiffening substance binding the tails together, consistent with what we found at the specimen level: the Otago Museum case names horsehair and a sticky substance from the rats' own nest as the binding material, and the 2021 Estonian case reportedly involved the tails becoming stuck in a constructed tunnel rather than a knot being tied.
What isn't
- No single mechanism has been experimentally confirmed — multiple theories are proposed, none tested against each other. Sources we checked name at least three candidate binding agents (sap, blood, feces or sebum acting as glue; horsehair or nesting material; cold-weather stiffening) and one proposed behavioral factor (a grasping tail reflex in young black rats), but no source we found describes an experiment that isolated which factor actually causes a given case, as opposed to being present alongside it.
- Whether any specific historical specimen is a hoax remains an open question no source we found actually resolves. Guinness World Records states plainly that "some zoologists remain sceptical about the existence of naturally-occurring rat kings, instead choosing to believe that past cases are man-made hoaxes" — but names no specific specimen as a confirmed fabrication, and neither does any other source we checked. The skepticism itself is documented; which cases it applies to is not.
- Even Miljutin himself did not cite his own records when asked, in 2021, how rare the new case was — he cited Wikipedia. Per ERR's own quote of him: "The last finding was in 2005 to my knowledge and according to Wikipedia, that was the only finding in the world this century. And now this one is the second this century." The author of the field's one peer-reviewed count deferred to a crowd-sourced encyclopedia rather than his own 2007 paper to confirm the new find's rarity — which suggests no one, including him, maintains an authoritative running total today. We found no updated count anywhere.
- We did not read Miljutin's 2007 paper ourselves. As stated in the source trail above, both the publisher's own PDF and a ResearchGate copy failed to return readable text to our fetcher. The "58 sightings, six museum-preserved" figure rests on National Geographic's reporting of the paper, not our own reading of it.
Verdict
Rat kings are real. That part is settled by physical specimens we could independently trace to named museums and dates, by a 2021 live case examined firsthand by the field's leading researcher, and by an independent expert who reviewed the evidence and confirmed it rather than dismissing it as folklore. What isn't settled is almost everything past that baseline fact: no single tested mechanism explains how the tails actually bind, no source names which older specimens (if any) are the fabrications that "some zoologists" suspect exist, and the researcher most qualified to keep an exact count doesn't appear to keep one himself — he checked Wikipedia, same as everyone else would.