A global mathematical investigation of a predator-prey model

We construct a global bifurcation diagram of the plane differential system $${l} \dot x = x(1-x)-x y/(a+x^2), \dot y = y(\delta-\beta y/x), x(t)>0, y(t)>0, a>0, \delta>0, \beta>0,$$ which describes the predator-prey interaction.