The flying primate hypothesis explains how a structured social bat colony can evolve into primates and homo neanderthalis. The homo neanderthalis in the setting of global warming and extremes of climate living in isolated environment without food and water adapts to form the smaller homo floresiensis species. The homo neanderthalis and homo floresiensis species having nanoarchaeal symbiosis had expansion of the cerebellum and a small cerebral cortical structure. The homo floresiensis and homo neanderthalis themselves serve as a reservoir for retroviral infections. The retroviruses from the homo floresiensis or the flying primate bat colony would have integrated into the genome of the homo floresiensis generating the homo sapien species. The homo sapien species with a large prefrontal cortex would have evolved in the sequential way from homo floresiensis. The homo neanderthalic and homo floresiensis species having evolved out of a bat colony can serve as a reservoir for viral infections can thrive in the neanderthalic and floresiensis population which are resistant to them, but can infect and exterminate the homo sapien and neanderthalic-sapien hybrid population.