Toad Explosions

A reputation for elegance and order in Hamburg, Germany, was fractured in April by an alarming outbreak of exploding toads. Local amphibians swelled up to triple their ordinary size, then burst—audibly and always at night—with enough force to propel their parts up to three feet. City residents were left to puzzle over a trail of corpses. The site of the happenings was quickly dubbed "the pond of death," and officials scrambled for explanations. Water tests revealed no unusual bacteria or viruses. Suggestions that South American racehorses running nearby had introduced an alien fungus were disproved.

Meanwhile, toads kept going pop in the night. "It's absolutely strange," Janne Kloepper, a veterinarian at the Institute for Hygiene and the Environment, told local media. "We have a really unique story here in Hamburg. This phenomenon really doesn't seem to have appeared anywhere before."

She wasn't able to say that for long. Reports of more exploding toads soon emerged from across the border in Denmark. As the death toll climbed above 1,000 in the space of just a few days, the mystery deepened. No other aquatic or amphibious wildlife seemed to be affected in either country. Even frogs were doing just fine.

Berlin veterinarian Frank Mutschmann descended on Hamburg to collect corpses and perform autopsies. Examining countless specimens, Mutschmann noticed that all the animals had curiously identical incisions in their midsections. Further inspection revealed the cause: Aggressive crows had developed a taste for toads' livers and were plucking them out in lightning-quick strikes. The toads had apparently tried to frighten off the predators by puffing themselves up, and the crow-beak punctures had caused the toads' blood vessels and lungs to rupture.

"The crows are clever," Mutschmann observed. "They learn quickly from watching other crows how to get the livers." The residents of Hamburg remain on guard. Two years ago, a flock of crows attacked joggers in a city park, pecking at one woman's head as though under the direction of Alfred Hitchcock. —Trey Popp

Discover Magazine, August 2005, Vol 27, No 1, Pg 25