Central place foraging in Rattus norvegicus

Rats could accumulate food pellets by responding on one lever, and then gain access to them by responding on a second lever N times (experiment 1), by ceasing to respond on the first lever for D seconds (experiment 2), or by making a single, vigorous response of force W on the second lever (experiment 3). The design may be viewed as an analogue of central place foraging. As N (distance), D (time), or W (effort) increased, load (the average number of pellets accumulated before they were eaten) also increased. It appeared that delay mediated the effect of the other independent variables. A simple model of central place foraging was shown to accommodate the data.