I have no problem believing these stories.

It's easy to be picky when you are well fed.

I don't really care for salmon, carrots, yams, or tea. But if I went a few days or a week without eating, I believe that I would love to consume that stuff!

My point is, if these picky snakes were on their own they would eat any rodents that come their way. That being said, there's another point as well.