(CNN) -- They're big, strong, and fierce -- and they wear little blue booties.



The police dogs in Duesseldorf, Germany are now patrolling the pavement in protective shoes that their police-officer handlers strap onto their paws.



The reason? Too many glass shards left by beer drinkers in the city center, said Andre Hartwich, a spokesman for police in Duesseldorf.



"We wondered how can we protect our dogs' feet against glass," said Hartwich. "We looked on the Internet and found these shoes."



Beer drinkers along the Rhine River and in the city's Altstadt, or Old Town, often discard beer bottles on pebbled walkways. Broken glass poses a problem for the police force's 20 German Shepherds and Belgian Shepherds, Hartwich said.



In addition, hooligans and vandals leave behind glass shards around New Year's Eve and during the city's famous Carnival celebrations.



So what's a dog to do?



Their handlers shelled out 60 euros -- $89 -- for shoes that are also worn by dogs who walk on ice in Alaska.



Dogs need a month of training to get used to wearing the shoes, Hartwich said.



"We have to condition the dogs to the shoes," he said. E-mail to a friend
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