Changing the lighting will help. A diffuse flash can help or if you prefer you can use daylight colored bulbs with some sort of diffuser (white cloth) over them. Compact fluorescents are great because they don't give off as much heat. Having one on each side of the snake will help eliminate shadows and give you even lighting.

You should try shooting those against a black background instead of on that grass. It helps bring out colors consistently.

Also, learning how to process the images on your computer (with Photoshop or the GIMP, or some similar program) can make a big difference.
-----
Chris Harrison
San Antonio, Texas