The paper focuses on the impact that the droughts have had and can have over the animal populations in the arid and semi-arid populations and attempts to quantifies the impact of droughton the probability of the extinction of the animal populations. The research also attempts to quantify the impacts of the changing climatic conditions and natural events on the populations of animals. The effects of droughts have been very severe on the animal populations which have their habitats in the arid and semi arid regions. The arid and semi-arid environments have had severe droughts which have affected the herbivorous ...