Hormonal and behavioral variation in pied tamarins housed in different management conditions

Pied tamarins are an endangered Amazonian primate that has limited breeding success in zoos. Unfortunately, little is known about their reproductive biology and adrenocortical activity. Objectives were: (1) determine if fecal hormones could be utilized to monitor gonadal and adrenocortical activity; (2) characterize male and female gonadal and adrenocortical hormones; and (3) determine if there were differences between adrenocortical activity and behavior in a nonbreeding, on-exhibit (NB-ON) pair compared to a breeding, off-exhibit (B-OFF) pair. Fecal samples were collected from four (two males; two females) individuals. Hormones were analyzed for fecal progesterone (FPM), androgen (FAM), and glucocorticoid (FGM) metabolites by enzyme immunoassay. Behavioral observations were conducted for 6 months. Data were collected on instantaneous behavior, location, and all occurrences of intraspecific behaviors. Fecal progesterone metabolites were validated by pregnancy (mean ± SE, pregnant: 28.47 ± 1.60 μg/g; nonpregnant: 8.63 ± 0.89 μg/g). Fecal androgen metabolites were higher (T = 31,971, P < 0.05) in the B-OFF male (863.66 ± 46.30 μg/g) than the NB-ON male (838.63 ± 60.70 μg/g). Fecal glucocorticoid metabolites were validated by response to veterinary procedure with elevated values (7.31 ± 1.48 μg/g) seven times the baseline (0.37 ± 0.04 μg/g) at 24-hr postphysical. Females had higher baseline FGM than the males (P < 0.05). Baseline FGM were higher (P < 0.05) in the NB-ON female (0.93 ± 0.03 μg/g) compared to the B-OFF female (0.38 ± 0.02 μg/g). Similarly, the NB-ON male's FGM baseline (0.71 ± 0.03 μg/g) were higher (P < 0.05) than the B-OFF male (0.21 ± 0.01 μg/g). Behavioral data revealed stereotypical behaviors in the NB-ON pair but no stereotypical behaviors in the B-OFF pair. Fecal hormone monitoring and behavioral analysis may provide insight on the limited breeding success of pied tamarins in zoos.