Assuming a genetic distance of 2% in hierofalcons corresponds to a divergence roughly 200,000–130,000 years ago, the 0.6–0.7% genetic distance in the peregrine falcon-Barbary falcon ("peregrinoid") complex suggests its current taxa evolved in the Late Pleistocene some 100,000 years ago or less, but before the Upper Paleolithic. The presumed time of divergence between peregrine falcons and Barbary falcons approximately coincides with the start of the last ice age, when desertification was prominent in North Africa and the Middle East and the Persian Gulf became a landlocked inland sea that slowly dried up. Populations of ancestral "peregrinoid" falcons living in marginal habitat at the fringe of the African-Middle Eastern desert belt either adapted (and might have become isolated; e.g., in the Persian Gulf region, which turned into semiarid habitat surrounded by vast deserts), left for better habitat, or became extinct. During interstadials, deserts receded and the aridland and humidland populations could expand to contact again, causing some limited gene flow. This scenario, by and large, parallels the proposed evolutionary history of the saker falcon in relation to the other hierofalcons; indeed, that group shows similar patterns of molecular paraphyly though it is of somewhat earlier origin.