How Stranger Encounters of Common Marmosets (Callithrix jacchus jacchus) Are Influenced by Family Members: the Quality of Behavior

The initial confrontations of 33 previously unfamiliar pairs of common marmosets were observed. Four types of pairs were used (alpha males/alpha females; alpha males/subdominant females; alpha females/subdominant males; subdominant males/sub-dominant females). Each dyad was tested in five different experimental conditions: (1) isolation of both individuals from their families, unilateral encounters in which either the (2) male’s or the (3) female’s family was visible to the dyad through a one-way screen, and interactive encounters in which either the (4) male’s or the (5) female’s family was present behind a wire screen. Pairs which included alpha females exhibited no affiliative, practically no sexual, but high levels of aggressive behaviors. Pairs which included subdominant females exhibited affiliative, high levels of sexual, and practically no aggressive behaviors. Behavior was reduced qualitatively as well as quantitatively with increasing presence of the families. Possible functional aspects of the results are discussed.

The initial confrontations of 33 previously unfamiliar pairs of common marmosets were observed. Four types of pairs were used (alpha males/alpha females; alpha males/subdominant females; alpha females/subdominant males; subdominant males/sub-dominant females). Each dyad was tested in five different experimental conditions: (1) isolation of both individuals from their families, unilateral encounters in which either the (2) male’s or the (3) female’s family was visible to the dyad through a one-way screen, and interactive encounters in which either the (4) male’s or the (5) female’s family was present behind a wire screen. Pairs which included alpha females exhibited no affiliative, practically no sexual, but high levels of aggressive behaviors. Pairs which included subdominant females exhibited affiliative, high levels of sexual, and practically no aggressive behaviors. Behavior was reduced qualitatively as well as quantitatively with increasing presence of the families. Possible functional aspects of the results are discussed.