Predator–prey dynamics in small indecisive groups

Determine the predator–prey interaction dynamics in small groups of animals that indecisively switch between solitary behavior and selfish herd behavior, resulting in unpredictable collective responses. The objective is to characterize how these dynamics manifest in small-group settings where individuals oscillate between fleeing and aggregating behaviors.

Background

The paper contrasts well-understood collective behaviors in large groups—such as flocking and the selfish herd effect—with the erratic, indecisive behaviors observed in small groups. While solitary animals typically flee or deceive predators, and large groups often show coordinated defenses, small groups unpredictably switch between solitary and collective strategies, complicating control and prediction.

The authors use sheep-dog trials as a natural experimental platform to study these small-group dynamics, proposing a stochastic model based on pressure (stimulus intensity) and lightness (response isotropy). They identify the fundamental gap that, despite extensive research on collective predator avoidance, the specific dynamics governing small indecisive groups remain unresolved, motivating their modeling and analysis.