BERLIN -- What's making toads puff up and seemingly explode in northern Europe? More than 1,000 toad corpses have been found at a pond in an upscale neighborhood in Hamburg and over the border in Denmark after bloating and bursting.
It's left onlookers baffled. The pond water in Hamburg has been tested, but its quality is no better or worse than elsewhere in the city. The toad remains have been checked for a virus or bacterium, but none has been found.
One German scientist studying the splattered amphibian remains has a theory: Hungry crows are pecking out their livers.
''The crows are clever," said Frank Mutschmann, a Berlin veterinarian who collected and tested specimens at the Hamburg pond. ''They learn quickly from watching other crows how to get the livers."
Based on the wounds, Mutschmann said, it appears that a bird pecks into the toad with its beak between the amphibian's chest and abdominal cavity, extracting the liver, at the same time that the toad is puffing itself up as a natural defense mechanism.
Then, because the liver is missing and there's a hole in the toad's body, the blood vessels and lungs burst and the other organs ooze out, he said.
As gruesome as it sounds, it isn't actually that unusual, he said.
''It's not unique -- it's in a city area, and that makes it spectacular," Mutschmann said.
There have also been reports of similar toad deaths in a pond near Laasby in central Jutland in Denmark.