Fecal Steroids of Breeding and Non-breeding Free-Ranging Black-Tufted Marmoset Females

Marmosets from the Callithrix genus (six species) are anthropoids distributed in many Brazilian biomes, but anthropogenic pressure is a risk for hybridization and virtually the extinction of some species. Despite this, only a few data are available on reproductive ecology, which is a gap in understanding the physiological modulation of the socio-sexual behavior of free-ranging marmosets. In this study, we characterized fecal concentrations of progesterone, estrogens, and glucocorticoids of six breeding and non-breeding females from two groups of free-ranging C. penicillata, which is the species with the largest geographical distribution and most important in hybridization studies. The fecal progesterone was significantly higher in females who gave birth than non-breeding females, which was linked to reproductive status. The levels of fecal estrogens and glucocorticoids did not differ between breeding and non-breeding females. The data are according to the few studies on steroid values of free-ranging and captive marmosets. This study shows the concentrations of progesterone and glucocorticoids in free-ranging C. penicillata for the first time. Overall, the high levels of progesterone associated with pregnancy in free-ranging C. penicillata as well as levels of estrogens and glucocorticoids close to those reported for other species, suggest a conserved pattern of hormonal secretion between Callithrix species that have been studied in captivity.