Spatial structures in simulations of animal grouping

We present numerical simulations of an animal grouping model based on individual behaviours of attraction, alignment and repulsion. We study the consequences on the simulated groups’ internal structures, of using different functions. These different functions which are adapted from the literature define the intensity, associated with these behaviours, as a distance function between individuals. We also investigate here the impacts of: the number of individuals, the number of influential neighbours and the strength of the alignment behaviour on the structures. We show that homogeneous groups can be identified when: the different functions used lead to a smooth transition from attraction to repulsion; alignment overcomes repulsion and attraction, in particular within this transition zone; and when there is a low number of influential neighbours. We also point out the fact that otherwise, the model results in heterogeneous internal structures, which take the form of a concentration of individuals in subgroups, in lines, or at the periphery of the groups.