Infanticide risk and infant defence in multi-male free-ranging sooty mangabeys, Cercocebus atys

Area of Science:

• Primate behavioral ecology
• Social behavior in mammals
• Evolutionary biology

Background:

• Male infanticide was considered rare in multi-male primate species.
• Recent research suggests infanticide occurs in these species.
• A model predicts age and rank influence infanticide by immigrant males.

Purpose of the Study:

• To investigate male infanticide in wild sooty mangabeys (Cercocebus atys).
• To test the prediction that dominant immigrant males are more likely to commit infanticide.
• To examine the protective roles of mothers and putative fathers against infanticide.

Main Methods:

• 11-month observational study of free-ranging sooty mangabeys in Taï National Park, Ivory Coast.
• Data collection during birth and mating seasons.
• Recording male interactions with mother-infant pairs and infant survival.

Main Results:

• Dominant immigrant males attacked mother-infant pairs more frequently than other males.
• Mothers often counter-attacked during male assaults.
• Putative fathers actively guarded infants and mothers during vulnerable periods.
• Only one of seven infants died despite numerous attacks by immigrant males.

Conclusions:

• Male infanticide does occur in wild sooty mangabeys.
• Dominance rank influences the likelihood of infanticidal behavior in immigrant males.
• Cooperation between mothers and fathers effectively protects infants from infanticide, challenging previous assumptions.