Vervoort, R.; Schmaltz, L. E.; Hooijmeijer, J. C.E.W.; Verkuil, Y. I.; Kempenaers, B.; Piersma, T.: Within- and between-year variation in the presence of individually marked Ruff Calidris pugnax at a stopover site during northward migration. Ardea 110 (1), pp. 41 - 59 (2022)
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.