In India the serpent is linked officially with Nakshatras 4 and 5 and linked with 9.
At the human scale the serpent is linked symbolically with Ida and Pingala and in combination with the Caduceus. At the celestial level, the serpent is linked with Draco and thus symbolically also with a dragon.
The original serpent is divided into two as
Rahu Serpens Caput
Ketu Serpends Cauda
The serpent represents ego, the carnal personality of man which keeps wanting the mundane pleasures. The ego is created by avidya or ignorance and this must be kept in check and channeled to discover the Truth. The peacock holding the serpent within its claws conveys this Truth.