Scientists believe that chimpanzees split from the lineage that would lead to modern day humans around six million years ago. While fossils of human ancestors are relatively well known, ancient chimpanzee fossils were not formally described until 2005.
Chimpanzees are listed as endangered by the International Union for the Conservation of Nature. Though there were an estimated one million chimpanzees at the start of the 20th century, current estimates put the current population at about one-fifth to one-third of that number. Many organizations are working to learn more about these amazing apes and ensure their survival for many years to come.