ABSTRACT Mycophagy (fungi consumption) is an important animal‐ecosystem interaction and provides nutrients for numerous mammalian taxa, such as primates. Although mushroom consumption is a widespread behavior documented in about a quarter of all known primate species, surprisingly little is known about their use of mushrooms as either a staple or fallback food and the relationship between mushroom availability and consumption. We used direct observational data on mushroom consumption in the diet of three sympatric primate species: chimpanzees ( Pan troglodytes schweinfurthii ) and red‐tailed monkeys ( Cercopithecus ascanius ) from 2019 to 2022, and yellow baboons ( Papio cynocephalus ) from 2015 to 2022 in a mosaic woodland habitat in the Issa valley, western Tanzania, to address these gaps. We analyzed mushroom consumption patterns and assessed mushroom availability from line transects for a period of 15 months (Oct 2022—Dec 2023). Our findings show that mushrooms were a consistent dietary component for all three species during the wet season (October–April; chimpanzees—4%, baboons—17% and red‐tailed monkeys—4%), while baboons also continued to consume mushrooms (~11% of their annual diet) even when availability was low outside the wet season. This is also the first report of mushroom consumption by red‐tailed monkeys. We conclude that mushrooms serve as a fallback resource for Issa chimpanzees and red‐tailed monkeys, while they represent a preferred food for Issa baboons. We contextualize mushroom consumption as a potential strategy of niche partitioning to reduce interspecific feeding competition and underscore the importance of mycophagy and its role in primate dietary ecology and human evolution.
Schulze et al. (2025) studied this question.