Bismarck.Josiahflaming said:
»Religions define what sin is for you. But plenty of species out there see behaviors given as the same connotations you might view as "sinful" and in response remove members of their tribes for it without ever organizing into a religion etc.
Religions define what sin is for themselves and their followers. The followers decide what sins they will and will not commit.
Examples: All the Catholics on birth control, all the Jews eating cheeseburgers, all the Muslims who indulge in alcohol.
Non religious tribes still have taboos. Having no real legal system they cannot have laws but taboos serve the same function.
We are the only existent species that believes in sin. When a lion takes over a pride he usually kills all the cubs. This is biology. The cubs are not sinful and neither is he.