The study of behavioural gender differences among Callitrichid primates

has been generally neglected. We describe evidence from experimental studies in

which adult female tamarins (Saguinus) and marmosets (Callithrix) demonstrate priority

of access to food that is spatially and temporarily restricted. Differences in behavioural

strategies between both reproductive and non-reproductive females, and males, are

consistent with differences between the genera in their feeding ecology and social

organisation. They are also functionally plausible. A recent study gives preliminary

data to show that, although mated females in family groups of common marmosets

demonstrate priority of access to food sources, overall there are differences in

responsiveness that may be influenced by factors such as the time of feeding, energy

content and preference of food.

Callithrix jacchus (common marmoset) young receive care from mothers and fathers during early stages of development. In order to evaluate the compensatory care given by mothers when fathers were not giving their usual care, three families of marmosets, in which the fathers evidenced low levels of care from the time of the birth of the young, and two families in which the level of paternal care giving was normal were studied. In two of the low care families, and one of the normal families, the father was removed at 15 days after birth; in the other two families the fathers were removed at 30 days after birth. Data as to duration of care giving by the mother, care giving by the father, and contact between the two offspring (typically the common marmoset gives birth to twins) were recorded from the time of birth through two days after separation. Although the mothers compensated for the low levels of care given by the fathers, the total amount of time spent in care giving did not differ from that of the normal families, in those cases where separation took place at 15 days. In the case of the 30 day separation families, the total time of care giving in the lowcare family was lower than that of the normal family. Contact time between twins also differed between the 15 and 30 day separation families. The results indicate that compensatory care giving can be induced in the common marmoset.