YAMANASHI, Y.; MATSUNAGA, M.; SHIMADA, K.; KADO, R.; TANAKA, M. Introducing tool-based feeders to zoo-housed chimpanzees as a cognitive challenge: spontaneous acquisition of new types of tool use and effects on behaviours and use of space. Journal of Zoo and Aquarium Research, [S. l.], v. 4, n. 3, p. 147–155, 2016. DOI: 10.19227/jzar.v4i3.235. Disponível em: https://jzar.org/jzar/article/view/235. Acesso em: 19 jan. 2022.