Yogasanas are named based on the animal or thing they resemble, or the person who “invented” it.
This asana is named after a cobra as the asana lifts the upper body up while the lower body is rested on the floor, resembling a cobra lifting its hood up. Various schools of yoga have various ways to perform this asana. In some schools, the asana is performed without putting any weight on the hands and lifting the upper body only with the strength and elasticity of the spine.
Bhujangasana is the most popular asana and it is also called a Miraculous asana because of its back strengthening abilities.
In Hindu tradition and culture, The cobra is one of the most sacred creatures. There are various cobras mentioned all over the mythology.
Adishesha or anantha is the cobra on which Vishnu lies, he is also the snake who protects Vasudeva and lord Krishna while the former carried Krishna to Yashoda.
Even today, a story is narrated in Kukke subramanya, a district in Karnataka, where a huge cave is said to have been carved by Vasuki, the king of snakes after he fought with Garuda, vishnu’s vahana.
It is rumoured that the cave leads all the way to kashi.
Bhujanga, or the cobra is the only snake that can lift its hood up through continuous control over its muscular system. It is said that this was achieved through the change in the nervous system during the evolution. Other snakes do not have this capacity. This information is fascinating when compared to bhujangasana, as this asana is mainly beneficial to the spine and is said to help with various neurological issues.
Probably this is why In yogic lore, the spine is depicted as a cobra coiling upwards when the kundalini energy is awakened.
While performing this asana without using the hands, the body naturally moves up while u inhale and fill your belly and moves down when you exhale. This rhythmic movement looks very much like a cobra with its hood up and swaying up and down.
This is probably another reason why the asana got its name.