A Fascinating Story of Exploding Toads and Clever Crows

In April 2005, a small pond in Hamburg, Germany became the center of a great mystery, rather repulsive in nature. A documentary film made on the phenomenon reported:

“About 1,000 dead toads were discovered lying around the edges. Their bodies appeared to have exploded. Eye-witnesses said they swelled up to about three-and-a-half times their normal size and then simply burst. And they burst with such an explosive force that their entrails were blown over several square meters.”

For several weeks, the common European toads in question received international attention. Scientists were totally baffled, unable to provide an explanation for the unnatural deaths. Health officials panicked – they suspected a virus spread by South American race horses from a nearby track. The tabloid press had a field day with the story, labelling the area ‘The Pond of Death’. Things got worse when the epidemic spread across the border to a nearby Danish lake.


Photo: Wikimedia Commons

All the speculation was finally put to rest when Frank Mutschmann, one of Germany’s top experts on amphibians, cracked the case. And the explanation was even more shocking than the toads’ violent deaths. The massacre was, apparently, the work of a highly intelligent species of crows.

Frank examined both living and dead specimens of the Hamburg toads. What he found was truly chilling – identical circular incisions on their backs, just the size of a bird’s beak. He also figured out that all the amphibians had their livers missing.


Photo: YouTube caption

“There were no bite or scratch marks, so we knew the toads weren’t being attacked by a raccoon or a rat, which would have also eaten the entire toad,” Frank said. “It was clearly the work of crows, which are clever enough to know the toad’s skin is toxic and realize the liver is the only part worth eating.”

“Only once the liver is gone does the toad realize it’s being attacked. It puffs itself up as a natural defence mechanism. But since it doesn’t have a diaphragm or ribs, without the liver there is nothing to hold the rest of its organs in. The lungs stretch out of all proportion and rip; the rest of the organs simply expel themselves.”


Photo: Benutzer:BS Thurner Hof

According to the documentary, “No one knows how they (the crows) learned where the liver was located. But we do know that toad’s skin is so poisonous that many animals can have a fatal reaction to it. But, the liver is so nutritious, it’s worth working out how to extract it safely.” And that’s exactly what the clever crows did.

One of the world’s earliest cases of exploding toads was recorded in Germany in 1968. Similar cases have been observed in Belgium, Denmark and the US. But no other case was as gruesome or grisly as the Hamburg incident. Incidentally, it happened during the toads’ mating season. “They would have noticed something as the crow pecked at them, but it wouldn’t have been particularly painful,” said Frank.


Toads are very much loved by the Germans. In fact, they are a protected species over there. Frank said he had several angry e-mails from concerned citizens. “But there’s no reason to worry It’s just a part of nature,” he added.

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