“…The "attraction", "repulsion" and "velocity mimicking" are loosely stated here and can take a wide range of forms. This modeling based on social forces finds its roots in the works of [1,27] for fish schooling and it has been widely used, expanded, and improved by theoretical biologists, physicists and applied mathematicians; see [15,34,29,24,30,44,45,3,31,32,19] and the references therein. This approach has been made much more specific for particular animals and species as in [5,4,47,25] for fish (studying migration patterns for the capelin around Iceland) and in [2,26] for birds (starlings grouping in Rome).…”