A night time drop is used by some breeders to induce breeding, although many breeders also have success without it.

The idea of a night time drop for non-breeding snakes is talked about in many older books on snake care because years ago while keepers were still trying to figure how to successfully keep these animals, they tried to mimic their natural conditions as much as possible. With all we know today about the captive husbandry of reptiles, a night time drop just isn't something thats commonly done anymore.

-adam