KEEL BACK:
There are different types of keel backs. They are checkered keel backs, blue stripped keel back, Oliv Aceous Keelback, Green Keelback. The keel backs live in both fresh water and fields.
1. Checkered Keelback (Xenochrophis piscator):
This snake is found in tanks, paddy fields, pools and rivers. This snake is the cruelest among Indian snakes with the exception of the Echis. This snake strikes rapidly with great determination holding on tenaciously. Prior to striking it flattens its fore body. It is an extremely active snake, capable of jumping clear off the ground and will do so repeatedly if pursued.
2. Buffstriped Keel Back (Amphiesma stolata)
Local Names: Bengali - Hele sap; Marathi - Naneti; Telugu - Wannapam; Tamil - Nirkatanpambu.
3. Oliv Aceous Keelback (Atretium schistosum)
Local Names: Telugu Na/la wahlagillee pam, Kanarese Barmmya.
4. Green Keelback (Macropisthodon plumbicolor)
Local Names. Tamil Pachai nagam; Marathi Hara samp, Gavathia, Gautya sap.
It is somewhat similar to the green pit vipers. The shield on the head of the Green Keelback distinguishes it from the green pit vipers.
The snake is found in the hills and it favors altitudes between 600-1800 m. This snake is gentle and inoffensive and erects its fore body and flattens its neck like a cobra, hence the name `green cobra`. Though often seen in grass and scrub during daytime it restricts its movements to the night.
For Further Details: http://en.wikipedia.org/wiki/Keel_Back