This is a Zen story I really love, and wanted to share:
"In one life, Buddha chose to be a deer, and he became the leader of a large herd. The king at the time was a hunter, and his subjects thought to trap some beasts in a canyon so that the king could come there to hunt. They arranged an elaborate trap and then chased two herds of deer from different directions into it. It worked flawlessly, and in a very short time thousands of deer were trapped. When the king came, he saw the majesty of the two leaders of herds and told his subjects that they weren't to be sacrificed. Nevertheless, the 'Buddha deer' chose to be the first one sacrificed. Seeing this, the subjects of the king went to tell him that one of the leaders was volunteering to be sacrificed to save the others from being killed that day.
The king came and spoke with the Buddha deer, saying that his life was spared. But the deer would hear nothing of it, for how could he serve his herd if he could let them die so that he could live? The king agreed to set his herd free, but the Buddha deer replied, 'My gracious king, I cannot walk away and allow my herd to go free, for that means that I will be the cause of suffering for all the deer of the other herd.'
After much deliberation and many rounds of the Buddha deer sacrificing himself so no other creatures would suffer, the king ended up banning all hunting of wildlife in his kingdom. He ended up building a statue of the deer on the site of this conversation to remind all that we cannot live in happiness as long as others suffer."