Behavioral Ecology and Sociobiology

, Volume 46, Issue 6, pp 400–404

Offspring number in pygmy marmosets, Cebuella pygmaea*, in relation to group size and the number of adult males

  • Eckhard W. Heymann
  • Pekka Soini

DOI: 10.1007/s002650050635

Cite this article as:
Heymann, E. & Soini, P. Behav Ecol Sociobiol (1999) 46: 400. doi:10.1007/s002650050635


In many species of birds and mammals with a co-operative breeding and rearing system, offspring survival is positively related to the number of helpers. In the New World callitrichine primates (marmosets and tamarins), adult males are considered as particularly valuable helpers, and female reproductive success may depend strongly on the males' contribution to infant care. We analysed the number of offspring (infants, juveniles) in groups of wild pygmy marmosets, Cebuella pygmaea (Callitrichinae, Cebidae, Primates), in relation to the number of adult males and to the number of adult and subadult group members. In contrast to other callitrichines with a co-operative system of infant care, no relationship was found between the number of adult males and the number of infants and offspring. However, there was a significant positive relationship between the number of juveniles and the number of adult and subadult group members. The lack of a relationship between infant and adult-male number is interpreted as resulting from the reduced importance of adult males as helpers in pygmy marmosets in comparison to other callitrichines, probably due to the reduced costs of infant care. The relationship between the number of juveniles and the number of adult and subadult group members is in accordance with increased offspring survival in larger groups, as observed in other primates.

Key words Co-operative rearing Offspring survival Cebuella pygmaea Pygmy marmoset 

Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • Eckhard W. Heymann
    • 1
  • Pekka Soini
    • 2
  1. 1.Abteilung Verhaltensforschung und Ökologie Deutsches Primatenzentrum, Kellnerweg 4 D-37077 Göttingen, Germany e-mail: Tel.: +49-551-3851123, Fax: +49-551-3851291DE
  2. 2.Instituto de Investigaciones de la Amazonía Peruana (IIAP) Av. Abelardo Quiñones km 2, Apartado 784, Iquitos, Perú

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