(under construction)

The focus of the Macaca Nigra Project currently lies on research. We have initiated studies on male and female sexual signals, which involve several Indonesian and international students and scientists. Using an integrative approach, we currently investigate the adaptive significance of the signals, their physiological correlates and their effect on male reproductive success. The research will contribute significantly to our understanding of the function of sexual signals in primates and thus to the growing field of research in primate sexual selection.

In addition, we started basic studies on the ecology and reproductive biology of wild Sulawesi crested black macaques, focussing on two groups living in mixed habitat. The generated knowledge will be important for the management of this species.




Social determinants of physiological stress and health in wild crested macaques (Macaca nigra)
Céline Bret, PhD student, German Primate Center, Germany

The quality and quantity of social relationships influences the individual risk of mortality in humans and animals alike. The buffering effect social relationships may have on acute and chronic stressors have been particularly invoked in this respect. Chronically elevated glucocorticoid levels have been shown to suppress the immune system and, thus, to increase susceptibility to parasites and disease, and thereby mortality in a variety of taxa. Furthermore, more recent studies on personality suggest that certain personality traits also impact individual immune response and healthiness.

In our study, we therefore aim at investigating this relationship in a wild population of a highly tolerant primate species, the crested macaque.

The study will be carried out by combining detailed analysis of behavioural data, including social network analysis, with data on physiological stress, and from a set of non-invasively collected health markers.


 The stress factor: Examining anthropogenic sources of stress in wild M. nigra
Dominique Bertrand, PhD student, University at Buffalo, USA

Ecotourism sites are often buttressed against villages. This proximity can cause conflict between human and animal populations.

Primate conservation status is often used as an indicator of the overall health of resident ecosystems. As such, it is important to understand the factors, both natural and anthropogenic, that contribute to poor primate fitness in the wild. In order to explore these factors,

In our study, we therefore examine two anthropogenic influences (tourism and range restriction) on stress-related behavior and physiology of M. nigra in Tangkoko, over the course of one year, beginning in the fall of 2014. Specifically, our aim is to pinpoint which aspects of tourism and crop-raiding defense are most stressful in order to recommend management adjustments that will bring Tangkoko in closer alignment with its conservation goals.


Intergroup interations in crested black macaques (Macaca nigra)
Laura Martinez Inigo, PhD student

Intergroup interactions are key aspects of primate social life. They can determine space usage and access to resources. This, in turn, can have enormous impacts on intragroup dynamics such as behaviour and demography. Despite their importance, intergroup interactions are one of the least studied parts of primate socio-ecology.

This project aims to address the topic in an integrative manner investigating the questions:


  • Do groups avoid encountering each other? If so, what mechanisms do they use?
  • What factors explain whether an individual participates in an intergroup conflict?
  • Do intergroup encounters alter the behavioural patterns within the groups?
  • Is there intergroup dominance? If so, what factors determine it and what are the consequences?

These questions will be explored by studying neighbouring groups of black crested macaques. Data collection will involve behavioural observations, spatial data collection and non-invasive sample collection for DNA analyses.


Factors Influencing Incomplete Male Monopolization of Females in Crested Macaques (Macaca nigra)
Lisa Danish, Postdoc, German Primate Center, Germany

Among the mammals, human and nonhuman primates are unusual in the degree of variation in male ability to monopolize sexual access to females. Recent data from a number of primate taxa, however, reveal the substantial variation in male reproductive skew.

Since male reproductive skew varies, high ranking males are not always able to completely monopolize paternity. Multiple hypotheses have been proposed to explain this incomplete monopolization and include:

1) functional costs and tradeoffs;

2) female strategies;

3) alternative male mating strategies; and

4) the Concession Model.

I will test these hypotheses by integrating behavioral, genetic, and physiological data from data collected on crested macaques (Macaca nigra). Data and sample collection, and analysis at Bogor Agricultural University will take place from October 1 2014- September 30 2016.