  Temperature plays a very important role in various biological processes like
the evolution of life, as it is anticipated that early life existed in a very
hot environment that eventually cooled down with time. In vitro experiments,
conducted with various active matter systems in anisotropic temperature
environments, show several interesting outcomes. Motivated by these experiments
and some simulation results, we study the collective behavior of self-propelled
hard rods with excluded volume interactions, moving on a substrate in two
dimensions and subjected to a small but finite external temperature gradient.
Using a coarse-grained hydrodynamic approach, we explore the behavior of the
system in the steady state and the stability both in the passive and active
limits.
