In this paper, the nonlinear dynamics of a two-dimensional discrete-time
system of Leslie type with simplified Holling type IV functional
response are reported. Possible codimension-two bifurcations (1:2, 1:3
and 1:4 strong resonances) are investigated under variation of two
parameters for certain critical values at the positive fixed point. For
each bifurcation, normal form coefficients along with its scenario are
investigated thoroughly. Besides, using numerical simulations, in
addition to confirming the results of our analyses, more behaviors are
extracted from the model, such as fractal structure, mode-locking
structure, etc. Our results generate and improve some known results and
show that the discrete model has richer dynamics than the continuous
one.