Wickler, W.; Nowak, C.: Häutung und andere Verhaltensweisen von Taenianotus triacanthus, einem Verwandten der Skorpionfische. Natur und Museum 99 (10), pp. 441 - 456 (1969)
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.