Kids jokes-Fire truck with Dog

A nursery school teacher was delivering a station wagon full of kids home one day when a fire truck zoomed past. Sitting in the front seat of the truck was a Dalmatian dog. The children started discussing the dog's duties.
"They use him to keep crowds back," said one child.
"No," said another, "he's just for good luck."
A third child brought the argument to a close. "They use the dogs,"
she said firmly, "to find the fire hydrants"