From the July 26, 1890 New York Times:

“A duel recently took place in a traveling circus temporarily stationed in a village outside Paris, and very curious were the consequences. ‘Two acrobats,’ says a dispatch to the London Daily Telegraph, ‘quarreled, and resolved to fight a duel. The place chosen was the ring–after the public performance, of course–the conditions being two shots at twenty-five paces. As usual, neither of the combatants was hurt, and their wounded honors being satisfied the incident terminated. The duelists and their seconds overlooked the presence of two members of their company, who were quietly munching nuts in a corner. These were two trained monkeys, who had been taught to ride around the ring as soldiers, and to fire pistols en route. The monkeys saw the performance of their masters, and when the way was clear they resolved to imitate it. Gravely loading their pistols they faced each other–not at twenty-five paces, but at five–and fired. They both fell dead, one with its head nearly blown off and the other shot in the breast. At the sound of the shots the master of the circus rushed in and found the bodies of the imitative duelists in the ring with the still smoking pistols lying beside them.”