The Metamorphoses

Pythagoras illustrates that there are other foods outside of the realm of meats. He describes the earth as one great provider of nutrition and sustinence-- man does not need to rely on the killing of meats to satiate his body. 

From this excerpt, Pythagoras also depicts that only beasts eat flesh. To his devil's advocates who state that horses, sheep, and cattle often graze on grass, he retorts (and makes the distinction) that only the savage beasts (such as lions, tigers, and bears) enjoy procuring their meat. Pythagoras also depicts carnivorous humans as people who are very selfish; people who eat, "flesh to be made from flesh; for a greedy body to fatten, by swallowing another body; for one creature to live by the death of another creature!"The Metamorphoses also gives significance into Pythagoras' teachings; the excerpt validates the foundations of ethical vegetarianism based on the notion that the killing of these animals for human consumption is morally wrong. Pythagoras provides us an excellent example of how human greed brought about an injustice to animals who had to suffer for man's consumption of meat. Pythagoras also illustrates that men in antiquity were able to think in terms of ethics and often used ethicality to differentiate between the civilized and the non-civilized, the man and barbarian.