An answer

Courtesy: Google search

Finally an answer to my long pondered question.. read "Yet another Onam" to know more..

I did a few research here and there (no I am very lazy to go to a library and explore so, I was Glued to google.. and researched.. there were many theories but this answer some what pacified me..

Here is the answer I took from a Website called “Haindava Keralam..”