Infant corpse carrying in Pan reflects maternal attachment and death context

Infant corpse carrying is widely observed in chimpanzees and bonobos, yet its underlying mechanisms remain debated. Analysing 83 published cases using Bayesian mixed-effects models, we show that ICC duration varies with infant age at death, cause of death, and site-level interbirth intervals, with longer carrying following disease-related deaths, older infant age, and slower life histories. These results suggest that variation in infant corpse carrying duration is parsimoniously accounted for by the persistence of maternal behavioural systems being modulated by carrying risk, dyadic bond strength, and life-history context rather than by mothers recognising death as an irreversible biological state. Given the close evolutionary relationship of Pan and Homo, this implies that the complex cognitive frameworks required to recognise deaths finality likely emerged in the hominin lineage after divergence from the Pan-Homo last common ancestor.