Survival chances of a prey swarm: how the cooperative interaction range affects the outcome

TL;DR

This study models how the interaction range among prey influences their collective escape success from predators, revealing an optimal intermediate range that maximizes survival chances based on prey group size and predator strength.

Contribution

It introduces a theoretical prey-predator model demonstrating the existence of an optimal interaction range for prey survival, linking interaction range to escape trajectory patterns.

Findings

Maximum survival occurs at intermediate interaction ranges.

Escape trajectories depend on interaction range.

Optimal survival depends on prey group size and predator strength.

Abstract

A swarm of preys when attacked by a predator is known to rely on their cooperative interactions to escape. Understanding such interactions of collectively moving preys and the emerging patterns of their escape trajectories still remain elusive. In this paper, we investigate how the range of cooperative interactions within a prey group affects the survival chances of the group while chased by a predator. As observed in nature, the interaction range of preys may vary due to their vision, age, or even physical structure. Based on a simple theoretical prey-predator model, here, we show that an optimality criterion for the survival can be established on the interaction range of preys. Very short range or long range interactions are shown to be inefficient for the escape mechanism. Interestingly, for an intermediate range of interaction, survival probability of the prey group is found to be maximum. Our analysis also shows that the nature of the escape trajectories strongly depends on the range of interactions between preys and corroborates with the naturally observed escape patterns. Moreover, we find that the optimal survival regime depends on the prey group size and also on the predator strength.