“Sweet are the uses of adversity
Which like the toad, ugly and venomous,
Wears yet a precious jewel in his head”
Shakespeare’s ‘As You Like It’ Act 2:1.13-14

There are a lot of references about Nagaratnam or Nagamani (Cobra Jewel) in Tamil and Sanskrit literature. But the strange thing about it is that even the most famous English playwright Shakespeare mentions in his play ‘As You Like It’. Instead of snake he says toad. Indeed any story will change when it travels 6,000 miles!

The story about the cobra jewel is that the cobras keep it inside their bodies and use it during night time to search for preys. Ancients believed that the Nagaratnam emits enough light to identify the prey.

The concept of the Nagaratnam has not been scientifically proven. But there are lot of stories about people being defrauded by the name of Nagaratnam. Gullible people pay millions of rupees for fake Nagamanis.

My research shows that they did not mean Nagaratnam/Cobra Jewel , but only the power of snakes to see in the dark. Ancient Tamils were good observers. They named snakes with different words and one of them is Katchevi. The meaning is Kan+Sevi=Eye+Ear. That means the snakes have a single body part which functions like both its eyes and ears.

People who have watched Nature programmes on TV channels could see the way snakes see their prey in the night. The body heat of the animals are perceived by snakes using infra red rays. A snake’s prey will appear highlighted red in its vision. This extrasensory ability is probably what is popularly known as the Nagaratnam/Cobra Jewel.

The organ that identifies the prey by this ray is in a pit under the eye. Modern research shows that the snakes can’t see or hear properly. Snakes have these heat sensory pits on their faces. Even a small change of temperature in its surrounding can be easily detected by the snakes. Snakes have got another organ called Jacobson’s Organ. Snakes stick their tongues out very often to sense smell. When the tongues are pulled back the Jacobson’s organ identify the smell, which may be a prey and provokes the snake to attack it.

Tamils haven’t named any other animal as “Eye-Ear “(Katchevi) except snakes. This shows their keen observation and scientific knowledge about animals.

Interesting it may sound that the Tamils used a simile “like a snake that heard thunder” (“idi ketta nagam pola nadunginaan”) he was shaken. This simile is used to describe one who is shaken and trembling out of fear. Snakes can’t hear properly but can feel vibrations through the ground. Poets like Kamban used this concept in their books.

We find the following references about the cobra jewel in Tamil and Sanskrit:

  • Kumara Sambhavam of Kalidasa: 2:38, 5:43, Raghuvamsam 6:49, 10:7, 11:59, 11:68,13:12, 17:63;Rtu Samharam 1:20
  • Tamil Aka Nanuru 72, 92, 138, 192, 372
  • Pura Nanuru 172, 294, 398
  • Kurunthokai 239
  • Natrinai 255
  • Kurinchipattu Lines 221,239

This is not an exhaustive list. We find such references in innumerable places.

The general theme is that snakes use the light of Nagaratnam (cobra jewel) and if they lose it, snakes become very upset.