  In this work we consider the question of whether a simple diffusive model can
explain the scent tracking behaviours found in nature. For this behaviour to
occur, both the concentration of a scent and its gradient must be above some
threshold. Applying these conditions to the solutions of various diffusion
equations, we find that a purely diffusive model cannot simultaneously satisfy
the tracking conditions when parameters are in the experimentally observed
range. This demonstrates the necessity of modelling odor dispersal with full
fluid dynamics, where non-linear phenomena such as turbulence play a critical
role.
