Sometimes snakes will strike, constrict, but not eat (various reasons). Sometimes they can't find the head and just give up trying after a while (especially if it is a f/t and it is now cold). Some snakes are just really picky eaters. Some won't eat f/t at all, some won't eat white rats/mice, some won't eat male mice, etc. Then some won't eat for weeks, then all of a suddent it just kicks back in.

I have a female Albino that will not eat under any circumstances in any thing bigger than a 32qt tub (in a rack). She won't eat in terrariums/aquariums and stopped eating when I put her in a 41 qt tub. Some are just real picky eaters and have to be 100% comfortable to eat. Once I moved her back to 32qt she still didn't eat again for 3 weeks

In the wild snakes don't eat like clock work every 5-7 days like in captivity. Since Reptiles are cold blooded, they don't require the energy mammals need to keep their body regulated so they don't have to eat as often.