Dominance fades with distance: an experiment on food competition in long-tailed macaques (Macaca fascicularis).

Dominant animals often can suppress the competitive behavior of subordinates by overt aggression or by their mere presence. This experiment on pairs of long-tailed macaque females explored whether this effect of dominant animals is influenced by interindividual distance. A dominant and a subordinate, but stronger, animal could compete for food by a tug-of-war on a bar. The animals were separated by 2 grids, spaced at either 30 or 100 cm. At 30 cm, 7 of 8 subordinate subjects either did not pull the bar or did not obtain a major share of the available food. In contrast, at 100 cm, all subordinate subjects obtained more food than the dominant. Thus, the dominant animals could suppress the competitive behavior of the subordinate only at the short interindividual distance, despite the fact that the dominant could not approach or attack even at the short distance and could be fully seen by the subordinate even at the large distance.