Dispersal, group formation and kinship in the black-faced lion tamarin (Leontopithecus caissara).

We report on (i) new group formation, (ii) sex differences in dispersal and (iii) dispersal distance over 6 years for 3 social groups of the black-faced lion tamarin (Leontopithecus caissara) in the vicinity of Ariri, São Paulo state, Brazil. The groups were: Bina (monitored for 74 months), BM5 (52 months) and Teca (13 months). Each group was censused once a week and monitored for 3 days each month.

Social and developmental influences on urinary androgen levels in young male white-faced marmosets (Callithrix geoffroyi).

Callitrichine primates (marmosets and tamarins) often remain in their natal groups beyond the time of sexual maturity. Although studies have characterized the development of female reproductive function in callitrichine offspring, less is known about the male reproductive development. To document reproductive development in male marmosets, we monitored urinary androgen (uA) excretion in males housed in a captive colony of white-faced marmosets (Callithrix geoffroyi).