As a symbol, a dog represents loyalty, fidelity, watchfulness, and nobility.

In shamanic tradition, the dog is a symbol for loyalty. "Dog medicine asks you to look at how readily your sense of loyalty is countermanded by your need for approval. There are several questions you need to consider, depending on the situation.
1) Have I recently forgotten that I owe my allegiance to my personal truth in life?
2) Is it possible that gossip or opinions of others have jaded my loyalty to a certain friend or group?
3) Have I denied or ignored someone who is trying to be my loyal friend?
4) Have I been loyal and true to my goals?"
(Jamie Sams & David Carson, Medicine Cards. - See the cards for the 'contrary meaning').

There is a connection with Sirius, which is also called the dog-star and is part of the Canis Maior constellation. (Canis is Latin for Dog).

There also is connection in Egyptian Mythology to Anubis, who is usually depicted as either a canine, or as a man with a canine head.