Near the beginning, the paper states that humans are extremely unusual in the rates of paternal investment that fathers do. With most species, the male dips out. Men don't always spend a lot of time on children, but they do have the wiring for it. It seems to be one of the many traits that sets humans apart from other species.
Hadza men spend enough time with their children that their T levels drop: https://pmc.ncbi.nlm.nih.gov/articles/PMC2674347/
Aka men are doting fathers to the point of letting their children suck on their nipples: https://www.theguardian.com/society/2005/jun/15/childrensser...
This is a nice survey of the role of fatherhood in various cultures, with a focus on foragers: https://anthro.vancouver.wsu.edu/media/documents/fa_role_201...
Near the beginning, the paper states that humans are extremely unusual in the rates of paternal investment that fathers do. With most species, the male dips out. Men don't always spend a lot of time on children, but they do have the wiring for it. It seems to be one of the many traits that sets humans apart from other species.