Stone Throwing as a Sexual Display in Wild Female Bearded Capuchin Monkeys, Sapajus libidinosus

Abstract

Capuchin monkeys (Sapajus spp.) in captive settings frequently manipulate and throw objects. In the wild, they may push or drop stones and sticks toward targets during inter- or intraspecific threat displays. In addition, female capuchin monkeys exhibit a broad repertoire of behaviors during their proceptive period, including facial expressions, vocalizations, stereotyped body postures, and touch-and-run behavior. This study reports stone throwing as a newly-described communicative behavior during the proceptive display of females in a group of bearded capuchin monkeys (S. libidinosus) in Serra da Capivara National Park, Brazil. During a two-year study, three females from one group were seen throwing stones at males during their proceptive phase. After this period, three other females in the same group exhibited the same behavior. Although it may be possible that this pattern is the result of several independent innovations by each female, the apparent absence of this behavior in other groups leads us to suggest that we have documented the diffusion of a new behavioral trait or tradition within this capuchin social group.

Capuchin monkey research priorities and urgent issues

“…because it indicates that the captive group or individuals are robust capuchins, providing more information than the blanket use of Cebus spp., a term that could be interpreted by researchers as specifically signifying gracile capuchins. There is currently a divide in the literature in which most field researchers working with robust capuchins publish their work as Sapajus in concert with the species and sometimes subspecies for the given location [e.g., Falotico & Ottoni, ; Fragaszy et al, ; Scarry, ] while captive researchers publish work with any captive robust capuchin monkey populations or medical research subjects variously as C. apella [Addessi et al, ; Phillips & Thompson, ; Wheeler et al, ], S. apella [Brito et al, ; Morton et al, ; Rimpley & Buchanan‐Smith, ], Sapajus spp. [Goulart et al, ], or S .…”

Diversity of nutcracking tool sites used bySapajus libidinosusin BrazilianCerrado

“…Since then, examples of spontaneous tool use by wild tufted capuchin monkeys ( Sapajus sp. [Lynch Alfaro et al, ]) have included the use of sticks to probe insect nests and dislodge lizards from rock cracks [Mannu & Ottoni, ] and to fish for termites [Souto et al, ] and the use of stone throwing as a form of communication [Falótico & Ottoni, ; Moura, ]. The vast majority of reported cases, however, refer to the pounding of stones to crack open encapsulated fruit (nutcracking [Fragaszy et al, ; Ottoni & Izar, ]), a behavior that is shared with chimpanzees and our own species [Fragaszy et al, ].…”

Sexual bias in probe tool manufacture and use by wild bearded capuchin monkeys

“…In this location, bearded capuchins of at least two groups were previously known to use stones not only to crack or smash fruits and seeds, but also to dig for roots, underground storage organs, and spider nests (Mannu and Ottoni, 2009;Moura and Lee, 2004). Most tools are used to obtain food, but there are exceptions, like stone banging in threatening displays (Moura, 2007), and throwing stones as a part of females' sexual display (Falótico and Ottoni, 2013).…”