Asnin, V.; Gorbonos, D.; Hadar, S.; Kol, B.; Levi, M.; Miyamoto, U.: High and low dimensions in the black hole negative mode. Classical and Quantum Gravity 24 (22), pp. 5527 - 5540 (2007)
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.