Brief communication: self-suckling in Barbary macaque (Macaca sylvanus) mothers before and after the death of their infant.

Abstract

We report here self-suckling in four wild female Barbary macaques (Macaca sylvanus), living in two troops (i.e. "Flat face" and "Large" troop) in the middle-Atlas Mountains, Morocco. The four females lost their infants due to predation or for unknown causes. Self-suckling was observed before and after the infants died in the four females living in the "Flat face" troop. When the infants were still alive, self-suckling was of short duration and it was probably a method to improve milk flow when the infant switched from one nipple to the other. After the infants died, self-suckling lasted significantly longer and the females were apparently drinking their own milk. Self-suckling was never observed among the four lactating females in the "Large" troop (including one monkey who lost her infant) and it could thus represent a cultural difference. Moreover, self-suckling after the death of an infant may be explained by the energetic and immunological benefits that a monkey may gain from drinking their own milk. Finally, self-suckling may have a stress-releasing effect on the mothers who have lost their infants.