Like most predators, spiders are opportunistic. They will gorge when prey is abundant, but can also fast for long periods of time without ill effects. Spiders do not get water from their food, however, so must drink from dew drops and other sources of moisture. Spiders that expend a great amount of energy by hunting “on foot” must eat more regularly than spiders that merely sit and wait in ambush (or in webs) for prey to come within range. Generally speaking, a spider may eat daily, or go several months without food. The average spider falls somewhere between those two extremes.
