I could not find an Official Army Regulation stating the dogs will outrank their handler. It appears to be a Tradition. Here is what I did find:
- According to a 2011 blog post by the US Military, military service dogs are all NCO – non commissioned officers – and are given a rank higher than their handler. This tradition is in place to maintain order while training and on missions. As a higher ranking officer, any mistreatment of the dog will result in severe disciplinary action for the handler, thus ensuring the dog is being treated well within the military
- TRADOC BLOG Post: A Unique Bond Every military working dog is an NCO – in tradition at least. Some say the custom was to prevent handlers from mistreating their dogs; hence, a dog is always one rank higher than its handler. https://www.army.mil/article/56965/