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Effects of rearing on aggression and subordination in papio monkeys
Anthony M Coelho1, Claud A Bramblett2
1Primate Ethology Laboratory, Department of Cardiopulmonary Disease, Southwest Foundation for Research and Education, San Antonio, Texas.
Insights
Short-term maternal deprivation in baboons (Papio cynocephalus) led to less aggressive and subordinate behaviors. Rearing environment significantly impacted social development in young monkeys.
Area of Science:
- Primate behavior
- Developmental psychology
- Animal social behavior
Background:
- Early life experiences, including maternal care and social environment, profoundly shape behavioral development.
- Understanding the long-term effects of maternal deprivation and peer-rearing is crucial for primate behavioral studies.
Purpose of the Study:
- To investigate the impact of early maternal deprivation (birth to 12 weeks) followed by peer-group rearing on aggressive and subordinate behaviors in baboons (Papio cynocephalus).
- To compare developmental trajectories of social behaviors between nursery-reared and mother-peer-reared baboons.
Main Methods:
- Comparison of nursery-reared (34 males, 30 females) and mother-peer-reared (11 males, 12 females) baboons.
- Behavioral observations conducted at late infancy (6–12 months) and juvenile stages (36–42 months).
- Analysis of focal animal data using a repeated measures ANOVA model in mixed social groups.
Main Results:
- Nursery-reared baboons exhibited generally lower levels of aggression and dominance behaviors (e.g., displacement) compared to mother-peer-reared individuals.
- Significant sex differences were observed, with males displaying more aggressive and subordinate behaviors than females.
- Behavioral rates varied significantly with age, with infants showing higher performance rates.
Conclusions:
- Early maternal deprivation followed by peer rearing appears to attenuate the development of aggressive and subordinate behaviors in baboons.
- Social rearing conditions and sex are critical factors influencing the development of social behaviors in Papio cynocephalus.
- Infant baboons display distinct behavioral patterns compared to juveniles, highlighting developmental changes in social interactions.
Abstract:
The objective of this study is to assess the effects of short-term maternal deprivation (birth to 12 weeks) followed by peer group rearing on the development of aggressive and subordinate behaviors in papio monkeys (superspecies - Papio cynocephalus). Nursery reared monkeys (34 males and 30 females) were compared with mother-peer reared monkeys (11 males and 12 females) in late infancy (6 to 12 months of age) and at the end of their juvenile stage (36 to 42 months of age) in social groups composed of 75% nursery reared subjects and 25% mother reared subjects. Focal animal data were analyzed with a repeated measure ANOVA model. In general, the nursery reared infants tended to be less aggressive than mother-peer reared infants and performed less dominance behaviors, such as displace. Significant sex differences were present in the performance of aggressive (♂ > ♀) and subordinate (♂ > ♀) behaviors. Significant age differences were observed, with infants having consistently higher rates of performance.

