In the yogic culture, the snake is a symbolism for kundalini, which is the unmanifest energy within you. The nature of kundalini is such that when it is still, you do not even know itexists. Only when it moves, you realize there is so much power within you. Until it moves, it is almost non-existent. Because of this, kundalini is symbolized as a snake, because a coiled-up snake is so hard to see unless it moves. Similarly, you do not see this coiled-up energy unless it moves. If your kundalini is aroused, miraculous things that you cannot believe possible will happen with you. An unleashing of a completely new level of energy begins and your body and everything behaves in a completely different way.
This is the reason for the symbolism of Shiva and a snake. It indicates that his energies have reached the peak. Mysticism and snakes cannot be separated because this creature has come endowed with a certain dimension of perception. This is a reptile that must be crawling on the ground, but Shiva has got it over his head to indicate that it is above even him. The indication is that in some ways, the snake is even better than Shiva.
The snake is one animal that is very comfortable with you if you are at ease. It just won’t do anything to you. A snake is also very sensitive to certain energies. Shiva has the snake around his throat. It is not just symbolic. There is a whole lot of science behind it. There are 114 chakras in the energy body. You can see them as 114 junction boxes or the confluence of nadis. Out of these 114, people are usually talking about the seven fundamental chakras in the system. Among these seven fundamental ones, the vishuddhi chakra is located in the pit of your throat. This particular chakra is very strongly associated with the snake. The vishuddhi is about stopping poison, and a snake carries poison. All these things are connected.
The word vishuddhi literally means “filter.” If your vishuddhi becomes powerful, you have the ability to filter everything that enters you. Shiva’s center is supposed to be vishuddhi, and he is also known as Vishakantha or Neelakantha because he filters all the poison. He doesn’t allow it to enter his system. Poisons are not necessarily that which you may consume through food. Poisons can enter you in so many ways: a wrong thought, a wrong emotion, a wrong idea, a wrong energy or a wrong impulse can poison your life. If your vishuddhi is active, it filters everything. It saves you from all these influences. In other words, once vishuddhi is very active, that person is so powerful within himself that whatever is around him does not influence him anymore. He is established within himself. He tends to become a very powerful being.