• Demographic parameters and events in wild moustached tamarins (Saguinus mystax)

      Löttker, Petra; Huck, Maren; Heymann, Eckhard W.; German Primate Centre (2004-12)
      This paper examines demographic events in the context of population structure and genetic relationships in groups of wild moustached tamarins (Saguinus mystax). We used a combination of long-term behavioral observations and genetic data from a total of eight groups from a population in northeastern Peruvian Amazonia. The mean group size was 6.0 (range=4–9), including 2.5 adult males and 1.8 adult females. Within-group relatedness was generally high (r=0.3), and most nonbreeding individuals were either natal or closely related to the respective same-sex breeder. The mean annual persistence of adults in the groups was 70% and 68% for males and females, respectively, and the reproductive tenure of one breeding pair lasted for at least 6 years. Migrations predominantly occurred after stability-disrupting events such as the immigration of new individuals and/or the loss of breeding individuals, or when groups were rather large. Migrations of both breeding and nonbreeding males and females occurred. Our results show that the hypothesis of Ferrari and Lopes Ferrari [Folia Primatologica 52:132–147, 1989] that tamarins live in smaller and less stable groups with lower relatedness compared to marmosets does not generally hold true. In contrast, we found that tamarin groups can consist of predominantly related individuals, and are stable as well. It is also apparent that a single demographic event can produce a chain of subsequent complex demographic changes.
    • Endocrine correlates of reproductive status in breeding and nonbreeding wild female Moustached Tamarins

      Löttker, Petra; Huck, Maren; Heymann, Eckhard W.; Heistermann, Michael; Abteilung Soziobiologie, Deutsches Primatenzentrum, Göttingen, Germany; Institut für Neuro- und Verhaltensbiologie, Abteilung Verhaltensbiologie, Westfälische Wilhelms-Universität Münster, Germany; Lehrstuhl für Verhaltensforschung, Universität Bielefeld, Germany; Abteilung Reproduktionsbiologie, Deutsches Primatenzentrum Göttingen, Germany (2004-08)
      In callitrichid primates, reproduction is usually restricted to a single female per group. Reproductive rate is high and the occurrence of a postpartum estrus can lead to simultaneous lactation and pregnancy. In contrast, nonreproductive females often show ovarian inactivity. However, most studies on callitrichid reproductive physiology have been conducted in captivity, where conditions differ considerably from those in the wild, so that reproductive conditions may be strongly modified. Using fecal estrogen and progestogen measurements to monitor female reproductive status in 2 groups of wild moustached tamarins (Saguinus mystax), we examined 1) whether reproductive females in free-ranging groups also show postpartum estrus and 2) whether nonreproductive females demonstrate signs of ovarian activity. In both reproductive females, clear changes in the excretion pattern of progestogen and estrogen metabolites over time in combination with information on parturition dates allowed us to differentiate between pregnancy, a period of postpartum ovarian inactivity lasting for 54 and 64–82 days, and a period of ovarian activity before conception. Nonreproductive females demonstrated temporal fluctuations in hormone concentrations and absolute hormone levels that were similar to ones in the breeding females during the phase of ovarian activity. The results suggest that, in contrast to most captive female tamarins, reproductive females in wild groups of moustached tamarins do not have a postpartum estrus and that nonreproductive females show ovarian activity despite the presence of a breeding female.We therefore conclude that findings from captivity should be only carefully compared to the situation in the wild.