There is significantly more genetic variability in one band of 50 chimpanzees than there is in the entire human species. This is no where near compatible with the age of the species, suggesting that at some point in history, at least once, the human population was almost entirely wiped out. The leading theory suggests that this evolutionary bottleneck may be directly linked to the catastrophic eruption of the Toba supervolcano in present day Indonesia about 70,000 years ago, which plunged the planet into a decade-long volcanic winter. This event was thought to have reduced the population of the ancestors of the current human species to between 3,000 and 10,000 individuals in central Africa. It has been shown conclusively that all humans alive today descend from that single homogeneous ancestral population.