<Note>Use of a novel human object as a masturbatory tool by a wild male chimpanzee at Bulindi, Uganda

Masturbation in a Free-ranging Male Long-tailed Macaque Macaca fascicularis (Raffles, 1821) on Mindanao Island, Philippines

“…This descriptive observation complements sporadic reports of masturbation of NHPs in the wild (Starin 2004;Inoue 2012;McLennan and van Dijk 2021). Masturbatory behavior provides a non-invasive opportunity to collect semen samples from wild populations, which is essential to understanding their reproductive biology (Thomsen 2001).…”

“…Masturbation or self-stimulation of the genitals is a natural, auto-erotic behavior observed in humans and non-human primates (NHPs), primarily in apes (Mootnick and Baker 1994;McLennan and van Dijk 2021) and Old-World monkeys (Starin 2004;Hasan et al 2021;Shalauddin et al 2021), and performed by both sexes either using hands, feet, mouth, or with "tools" (Cenni et al 2020). The behavior is also observed in several Macaca species -including Japanese macaques (Macaca fuscata) (Thomsen and Soltis 2004), rhesus macaques (M. mulatta) (Phoenix and Jensen 1973;Dubuc et al 2013), stumptailed macaques (M. arctoides) (Linnankoski et al 1993), and long-tailed macaques (M. fascicularis) (Bandini and Tennie 2018).…”