These snakes can be found by Leon if he destroys the boxes containing them. The snakes will attack him if the player does not kill it within a short range of time.
Upon taking out some of Leon's health, the snake is now harmless and will slither around the floor until being shot.
When killed, the Snake always drops an Egg.
Snakes are also found in Resident Evil 5, and are mostly found the same way, although at least one snake is roaming "free" near the Tricell camp near the Oil Field. If a snake is coiled up (as is always the case when "freed" from a container) it will make one lunge attempt at the player. Rarely the snake in RE5 will drop a Rotten Egg.