Relaxation Oscillation, Homoclinic Orbit and Limit Cycles in a Piecewise Smooth Predator–Prey Model

In this paper, we revisit a piecewise smooth fast-slow predator–prey model with Holling type I functional response and predator harvesting, where the harvesting rate is sufficiently small compared to the intrinsic growth rate of prey. The model undergoes two bifurcation mechanisms: (i) singular slow-fast cycle bifurcation, through which the model can have a unique and stable relaxation oscillation or homoclinic orbit; (ii) boundary equilibrium bifurcation, from which a unique and unstable limit cycle occurs. Additionally, we show the coexistence of a large-amplitude relaxation oscillation (or homoclinic orbit) and a small-amplitude limit cycle.