Hohmann, G.; Potts, K.; N'Guessan, A. K.; Fowler, A.; Mundry, R.; Ganzhorn, J. U.; Ortmann, S.: Plant foods consumed by Pan: Exploring the variation of nutritional ecology across Africa. American Journal of Physical Anthropology 141 (3), pp. 476 - 485 (2010)
Scientists studying a rare population of tool-using chimpanzees have found that aging can have a profound impact on their abilities—but not all chimps decline equally.