Normal hematologic and serum biochemical values of cotton-top tamarins (Saguinus oedipus).

We obtained whole-blood hematologic and serum biochemical values from 38 captive-bred cotton-top tamarins (Saguinus oedipus). Data were analyzed to determine the effect of sex on blood parameters. Significant differences between either the means or medians of male and female tamarins were found for creatinine, hematocrit, hemoglobin, RBC count, and PCV. These results establish baseline hematologic and serum biochemical values and provide a useful resource not previously available in the peer-reviewed literature for the clinical care of cotton-top tamarins, a critically endangered New World primate, in a captive setting.

Variation in oxytocin is related to variation in affiliative behavior in monogamous, pairbonded tamarins.

Oxytocin plays an important role in monogamous pairbonded female voles, but not in polygamous voles. Here we examined a socially monogamous cooperatively breeding primate where both sexes share in parental care and territory defense for within species variation in behavior and female and male oxytocin levels in 14 pairs of cotton-top tamarins (Saguinus oedipus). In order to obtain a stable chronic assessment of hormones and behavior, we observed behavior and collected urinary hormonal samples across the tamarins' 3-week ovulatory cycle. We found similar levels of urinary oxytocin in both sexes. However, basal urinary oxytocin levels varied 10-fold across pairs and pair-mates displayed similar oxytocin levels. Affiliative behavior (contact, grooming, sex) also varied greatly across the sample and explained more than half the variance in pair oxytocin levels. The variables accounting for variation in oxytocin levels differed by sex. Mutual contact and grooming explained most of the variance in female oxytocin levels, whereas sexual behavior explained most of the variance in male oxytocin levels. The initiation of contact by males and solicitation of sex by females were related to increased levels of oxytocin in both. This study demonstrates within-species variation in oxytocin that is directly related to levels of affiliative and sexual behavior. However, different behavioral mechanisms influence oxytocin levels in males and females and a strong pair relationship (as indexed by high levels of oxytocin) may require the activation of appropriate mechanisms for both sexes.

Social communication about unpalatable foods in tamarins (Saguinus oedipus).

Many monkeys show social facilitation in sampling novel, palatable foods but not in avoiding unpalatable foods. Cotton-top tamarins (Saguinus oedipus) socially learned to avoid a preferred food when it was made unpalatable but showed no aversion toward a food not made unpalatable. Only 33% sampled unpalatable tuna, and few sampled it again. In 3 of 8 groups, the socially induced aversion was long lasting, at least 15 weeks after food was made palatable again. Potential cues include facial reactions of disgust, alarm-call vocalizations, and reduction in food-associated calls. Behavioral coordination in cooperative infant care, communication about food, and well-established social relationships may explain social avoidance of unpalatable foods in tamarins and the absence of social avoidance in less cooperative species.