  In a recent article [arXiv:1108.5127] Park has shown that the four-state
predator-prey model studied earlier in [J. Stat. Mech, L05001 (2011)] belongs
to Directed Percolation (DP) universality class. It was claimed that predator
density is not a reasonable order parameter, as there are many absorbing
states; a suitably chosen order parameter shows DP critical behavior. In this
article, we argue that the configuration that does not have any predator is the
only dynamically accessible absorbing configuration, and the predator density
too settles to DP critical exponents after a long transient.
