Canid 3942 emerges from spacecraft
In the 2003 comedy film Good Boy! it's revealed that man's canine associates on Earth are actually an alien species sent to colonize Earth and subjugate its people thousands of years ago. However these colonists failed and instead became pets. For thousands of years the Dogs of the Dog Star (Sirius 7) waited for word that the mission was a success but received none so they sent Canid 3942 to check in on the progress. Canid 3942 however learned the truth yet feeling concerned for the terrestrial dog attempted to organize a fraud- an act- to fool the Greater Dane (the Dog Ruler) into believing the mission a success as failure would mean the mass exodus of Dogs from Earth. This ploy failed and the Greater Dane began the exodus only to find that these Earth dogs enjoy their status as 'pets'. At the end of the film the Greater Dane returns the Earth dogs to Earth and declares them a separate species (likely due to their inclination for servitude rather then for any biological distinctiveness as an isolated genome would still produce members of the same species just with certain traits becoming more or less prevalent due to population migration and Human's selectively breeding Dogs which may be a practice of the Sirius Dogs as well).
Society
Their society seems rather impersonal with individuals being referred to by a number or occupation. The Sirius Dog's agenda of subjugating other species (for which we only have one example and it's an example they abandon) is signs of Colonialism which is often seen as an expression of Imperialism.
Government
Sirius Dog society is governed by the Greater Dane. The term Greater seems to imply a title of Great beneath the Greater Dane. This is meant for humor in the film though the Great Dane of Earth is a man made breed and thus from a sociological viewpoint that takes into account an in-universe perspective Dane is most likely a title akin to Ruler in the language of the Sirius Dogs rather then a reference to Denmark which doesn't exist on their world. Another factor to consider is that terms are being translated in such a way that a Human Earthling can understand them. It's possible that 'Great Dane' is used as it's the term the Earthling boy can understand and the actual term is the Sirius Dog word for the breed. If such is the case then it'd suggest that Sirius Dog society is an 'ethnocracy' where the breed known on Earth as Great Danes hold political power.
Technology
The Dogs possess flying saucers propelled forward with thrusters of some kind but lifted off the ground with anti-gravity. Impressively even at such a small size the crafts are capable of traveling from Sirius 7 to Earth incredibly fast.
Notes
- The Sirius Dogs share some similarities with the Cats from the 1978 film, The Cat From Outer Space which may have been an inspiration for Good Boy!.