  Owing to the analogies between the problem of wealth redistribution with
taxation in a multi-agent society, we introduce and discuss a kinetic model
describing the statistical distributions in time of the sizes of groups of
biological systems with prey-predator dynamic. While the evolution of the mean
values is shown to be driven by a classical Lotka-Volterra system of
differential equations, it is shown that the time evolution of the probability
distributions of the size of groups of the two interacting species is heavily
dependent both on a kinetic redistribution operator and the degree of
randomness present in the system. Numerical experiments are given to clarify
the time-behavior of the distributions of groups of the species.
