Most reptiles, and most snakes in particular, are opportunistic feeders. They eat when there is food. A healthy snake is almost all muscle. And "hungry" could be a relative term with a snake. Most snakes will become more active when they are hungry. Many species in the morelia genus, and others, will perch themselves with their head pointed down and start caudal luring, wiggling the tip of their tail below their head so it appears as a worm to lure food in striking distance. It varies species to species and animal to animal.
And allot of snakes will eat themselves fat. They eat when there is food available, and if healthy can go for long periods when there is not. So if someone offers a healthy ball python an over sized rat every week, they will eat weather they need it or not.
