The system of Indian Astrology recognizes the heavenly bodies in our solar system only and considers rest of the constellations and galaxies as reference points in relation to the planets. The strength of the planets is judged based on the constellation they are moving against. The Indian system considers zodiac as epileptic rather than circular. Thus, each of the 12 houses is not 30 degrees but of varying degrees.
Indian Astrology differs considerably from the Chinese horoscope, which is based on the year of birth and believes that the year of birth indicates a certain phase or aspect of sixty year circle of time. Therefore you may find yourself born in the year of dog, horse or rat or even a dragon. Hence, people who are born in a particular animal year share certain common traits just like people born in common zodiac do.