"When Yeroen finally lost his top spot, he would often sit staring into the distance after a fight, an empty expression on his face. He was oblivious to the social activity around him and refused food for weeks. We thought he was sick, but the veterinarian found nothing wrong. Yeroen seemed a mere ghost of the impressive big shot he had been. I’ve never forgotten this image of a beaten and dejected Yeroen. When power was lost, the lights in him went out."

Frans de Waal