Banquo's spirit animal is a dog because he is very loyal to Macbeth. No matter how much wrong Macbeth did, he stuck right by his side. Even when Macbeth asks, Banquo said without hesitation that he would continue to be loyal, like dogs become loyal to their owners after feeling comfortable and earning their trust.Banquo is also calm and collected, much like older, well trained dogs. He does what Macbeth says and never questions it, he goes with the flow. When the witches told them their prophecy, Macbeth was thinking of everything he needed to do to fulfill that even if it mean hurting those in the way, whereas Banquo was just going to let it play out on its own and have the mentality that whatever happens happens just calm and collected.
Macbeth, however, spirit animal is a cat, because he will do what needs to be done to get what he wants. Cats are very independent and can be very ruthless. For example, he killed King Duncan because he knew if he did, he was a step closer to becoming king. He knew what had to be done and wasn't going to let anyone get in the way of him being king. Macbeth also is very kind to others and very understanding. For instance, he told Lady Macbeth he did not want to kill Duncan because he had been nothing but nice to them and a very well liked king. Within this same act, Macbeth showed a third trait of a cat when he got scared and backed out of killing Duncan. Just like him, cats get skittish and back away from things when aren't too sure about something.