Are animals efficient harvesters?

As animals move from one place to another there are patterns to their movements. It is hypothesized that these patterns are such that the net rate of food gain is maximized, and to test this hypothesis a model of a 'harvesting' animal is formulated. A harvesting animal is one whose movements are determined solely by previous movement and not by responses to sensory stimuli. Available data suggest that this harvesting model is inappropriate and that models which incorporate responses to sensory stimuli are likely to provide a better predictive understanding of animal movement patterns.