Visual encounters between families of cotton-top tamarins, Saguinus oedipus

Territorial, cooperatively-breeding, incest-avoiding organisms have various options for securing mates and resources for breeding. Both philopatry and dispersal have many costs and benefits, but all are likely to include assessment of neighbours. Five families of cotton-top tamarins, Saguinus oedipus, in a laboratory colony were allowed to watch each other through a peephole. These encounters took place in a naturalistic, neutral zone outwith their home room or cage. Parents looked more at neighbours than did offspring. Older monkeys looked more than younger. Females looked more than males. The clearest effect was of seniority: eldest offspring regardless of age were more eager lookers than were second-eldest than were third-eldest. The results make sense in terms of the monitoring of potential candidates for mate-recruitment or resource-acquisition, or for defense against outsiders with the same interests.