According to research released in November, plummeting temperatures and changing rainfall may have been the "primary factor" behind the extinction of three human ancestor species: Neanderthals, Homo erectus, and Homo heidelbergensis.
By examining more than 2,750 archaeological records, a team from Italy found that the climate cooled by up to 9 degrees Fahrenheit (5 degrees Celsius) on average per year ahead of the species' disappearances.
As the climate changed and their preferred food sources suffered in the cold, both species of Homo lost half of their ecological niche in Africa, Asia, and Europe. Neanderthals, meanwhile, lost 25%, according to the study.
"Even the brain powerhouse in the animal kingdom cannot survive climate change when it gets too extreme," study author Pasquale Raia, a paleontologist from the University of Naples, told ScienceAlert.