they do that. Rats and snakes are like peas and carrots. Best of friends. 
j/k.
Is the ball wild caught? If so they are real picky eaters, try a dark colored rat, if that doesn't work, try a dark gerbil. Should work out for you.
Also, if it's only been a week and he doesnt take food, don't push him to hard, offer every 3 days. They are still kind of confused about the whole pet deal.
Hope that helps.
Joel
>>I have a new ball python about 3 1/2 feet long, and about as big around as probably a baseball bat.
>>
>>Last night we tried to feed him for the first time since we got him last week,
>>
>>he was not only not interested in eating the rat, I think they have become friends, last time I looked at the rat he was asleep right beside my snake, the rat has been in there over twelve hours.
>>
>>What do you think, is he not hungry, or other problems?
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- Joel Smith
"If you're not part of the solution, you're still part of the problem"