Takayoshi Kano (1992); Frans de Waal (1987).
171
Zanna Clay and Frans de Waal (2013).
172
Robert Ardrey (1961).
173
Matt Cartmill (1993).
174
Gen"ichi Idani (1990); Takayoshi Kano (1992).
175
Steven Pinker (2011), p. 39; Richard Wrangham (2019), p. 98.
176
Adam Rutherford (2018), p. 105; Craig Stanford (1998).
177
Frans de Waal (1997), with Frans Lanting"s photography.
178
Amy Parish (1993).
179
Takayoshi Kano (1998), p. 410.
180