RATS ARE HEROES?

RAT S TURN HEROES WHEN CHUMS ARE IN PERIL BY SPURNING CHOCOLATE TO SAVE THEM.THIS WAS FOUND BY VIA A STUDY OF LAB RATS WHO LEARNT TO OPERATE 2 LEVERS ,1 WHICH FREED A FELLOW RAT AND THE OTHER IN A RISING TANK OF WATER.THE OTHER LEVER WOULD BE IGNORED EVEN THOUGH IT DISPENSED CHOCOLATE.