The whale routinely dives to depths of more than where it executes an average of four "lunges", to accumulate krill. Each gulp provides the whale with approximately of food. One whale can consume up to of food a day, leading scientists to conclude that the whale spends about three hours a day feeding to meet its energy requirements, roughly the same as humans. If prey "patches" are not sufficiently dense, or are located too deep in the water, the whale has to spend a larger portion of its day searching for food. One hunting technique is to circle schools of fish at high speed, frightening the fish into a tight ball, then turning on its side before engulfing the massed prey.