Why snakes

This passage led me to wondering why snakes are always the sneaky evil animal in old tales. This prompted me to google “why are snakes always evil” which led to the newfound knowledge that the whole snakes=evil thing was fairly widespread outside of christianity as well. I am still left wondering why snakes are always used to represent evil. Is it because they don’t have legs? In this passage the author refers to the Bible story of Adam and Eve and that pesky snake as the root of evil. Why not an evil bird or a lying meerkat?