According to a 2023 study, our human ancestors were reduced to around 1280 individuals between 813,000 and 930,000 years ago. Fortunately, we survived this bottleneck and our population began increasing again after that. This was a period marked by intense glaciation. The Ice Ages began about 2.4 million years ago and ended around 11,500 years ago. Source: [Hu 09/2023 - Genomic inference of a severe human bottleneck during the Early to Middle Pleistocene transition](zotero://select/items/1_QWTWVIYB) Hu, Wangjie, Ziqian Hao, Pengyuan Du, et al. “Genomic Inference of a Severe Human Bottleneck during the Early to Middle Pleistocene Transition.” _Science_ 381, no. 6661 (2023): 979–84. [https://doi.org/10.1126/science.abq7487](https://doi.org/10.1126/science.abq7487).