Neanderthals survived across most of Eurasia for approximately 400,000 years, longer than modern humans on Earth.[1] They lived in small, scattered groups with significant interbreeding, leading to the accumulation of harmful mutations.[1] Around 75,000 years before the present, they experienced near extinction during the Ice Age, when archaeological sites and skeletal remains were concentrated in southwestern Europe, particularly in France.[1][4] After the retreat of the ice around 65,000 years before the present, the surviving Neanderthals from southwestern France spread across Europe.[1][4] Genetic diversity in mitochondrial DNA was lost and only one lineage survived.[1] Later Neanderthals (60,000–40,000 BC) descended from this single lineage and experienced a sharp population decline around 45,000 BC, with a low around 42,000 BC.[4]