"What is the difference," a woman asked a keeper during a visit to the Zoo, "between the North American porcupine and the African porcupine ?"
"The principal difference between them Miss," the attendant replied, "is that the North American species has a longer prick." The woman fled in distress and anger to the Administration Building seller Mark the Chief Curator attempted to mollify her.
"I apologize for my staff Miss," he said. "It was an unfortunate choice of terms. What the keeper should have said is that the North American porcupine has a longer quill. Their pricks are exactly the same size."