Marmoset Social Cooperation

Courtesy www.rossparkzoo.com.

There is only one type of social cooperation in marmosets: alloparenting, its relation to cooperative breeding and group territorial defense. This is another debate within the researchers that work with the marmoset. Since the dominant, breeding female suppresses the other subordinant, "helper" females, can their involvement in taking care of the young be describes as any type of altruism? Some scientists think so. E W Heymann describes the marmosets as cooperative breeders, and therefore immediately imparts some sort of altruistic behavior to the marmoset. Heymann believes that the males in a semi-polyandrous marmoset group are essential for the group's success because they are almost the primary caregivers for infants and older offspring (Heymann, 1999). Interestingly, while other authors argue that it is the helper females are alloparents and help raise the offspring, Heymann considers adult males more valuable than other age-sex classes as helpers to the reproducing female. There most obvious reason why we see alloparenting in the marmosets, is that the cooperation of alloparents helps them both be more successful parents later (Lazaro-Perea, 2001). Also, we see cooperation in territorial defense in the marmoset, which may be a little harder to explain. This defense decreases the cost of defense of the breeding pair and can therefore help the fitness of the group. Also, the marmosets further down the hierarchy would have an innate desire to keep their place in the breeding hierarchy and protecting it from non-group members (Lazaro-Perea, 2001). Another minor reason for the territorial defensive displays would be to indicate to members of the other sex in the group that they are ready for parenting and territorial defense (Lazaro-Perea, 2001).