Immunity, a primeval feature of living organisms & is essential for reproduction and to face the challenges originating from seasonal variation and environmental threats as well. Present study reveals that how tropical animals have evolved a mechanism via melatonin to blaster the immune function to counteract seasonally recurrent stressors that may otherwise compromise immune functions. Finding suggests that melatonin is having an adaptive significance in balancing immune status in this rodent. It acts during winter as immuno-stimulator to save the squirrels from the adverse condition...