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Characterization of sexual traits in adolescent female Sulawesi crested black macaques (Macaca nigra) and male interest into these
Stefan Wedegärtner, Diploma student, Free University of Berlin, Germany - 2010 completed

In the present study, basic knowledge about female adolescence and female adolescent sex traits in a multi-male primate groups – species has been investigated. The focus of this study was the characterization of sexual traits in  adolescent female Sulawesi crested black macaques (Macaca nigra) and male interest into these. The crested black macaque is particularly applicable, since they live in huge multimale-multifemale groups and the females exhibit exaggerated sexual swellings. For this a number of basic adolescent characteristics like length of adolescence, length of pregnacny and reproductive capacity have been assessed. In addition, female sex skin swellings as well as sexual behaviour were characterized. Also, male interest in adolescent females has been determined. The study was carried out on three groups of animals in the Tangkoko Dua-Saudara Nature Reserve in Indonesia located on the northernmost tip of Sulawesi. I analyzed swelling pictures, fecal samples and sociosexual behaviours of nine study adolescent females. The results showed that onset of adolescence shows a seasonal pattern. Reproductive capacity of adolescent females is lower than in adult females. Sex skin swellings might function as a graded signal and also, Possibly, the adolescent female sex skin could represent a supernormal stimuli. Female specific sexual behaviour is poorly developed. Adult male interest in adolesent females is low, but increases during female adolescence, with low ranking adult male interest in adolescent females is probably higher than alpha-male interest.

In further research it would be interesting to assess wether a possible finding of a supernormal swelling size in adolescent Macaca nigra can be supported. For this, the study has to include a correctioin for body size.