Social cooperation/Altruism
Image courtesy of R. Sim-Dumais
Cotton-top tamarin's work together towards a common goal by performing cooperative behavior. Cooperative behavior is an act in which the "helpers" and receivers of help experience increased fitness. With cotton-top tamarins, cooperative behavior can be defined as raising and feeding the young, being vigilant of predators during foraging, and sending alarm signals to the group. The benefits of participating in cooperative behavior are: they increase the survival rate of the young, and the "helpers" aid in feeding and predator protection which decreases the energy cost of the parents (thus increasing the survival of the parents).
The cooperative behavior of the cotton-top tamarin is "selfish" cooperation. In "selfish" cooperation, all of individuals involved experience increased individual fitness that outweigh the cost to their fitness. The "selfish" cooperative behavior of "helping" siblings and non-family members of the tamarin social groups increases their chances of survival, they gain experience, it increases their chances of breeding, and they raise their chances of mate acquisition by staying with the group. In some cases, the members of the social group may also increase their probability of inheriting the dominant position by staying around for a long time and helping. The behavior of siblings that are "helpers" can also be considered kin altruism because by "helping" they increase the chances of their genes being successfully incorporated into the next generation (increased inclusive fitness).
