This paper reviews recent advances in field endocrinology, a focus as well as a method in primatology and behavioral ecology that permits the examination of social behavior and life history through hormonal investigations in natural settings. Endocrine data complements the traditional behavioral data collected by field scientists by providing quantitative measures for the examination of adaptive tradeoffs, costs of social strategies, and reproductive and social significance of mating events. Further, investigations of the physiological mechanisms of reproductive constraint provide tests of the adaptive significance of reproductive skew in cooperative and competitive breeders. Hormone data also can provide insights into the costs of competition and aggression and the role of temperament in individual reproductive success and the evolution of social systems. New, noninvasive methods for the collection of this information have augmented and expanded field endocrinology through the use of techniques that do not require potentially confounding physical or physiological manipulations. Specifically, urine and fecal samples can be collected from free-ranging animals and contain gonadal and adrenal hormones that parallel profiles of serum hormones. Sampling, preservation, extraction, and assay methods for the analysis of excreted steroids are reviewed along with the species and questions to which these methods have been applied.

This study examined whether fecal cortisol could be used as an index of stress responses. The stress responsiveness of fecal cortisol was tested with a stressor known to stimulate adrenal activity, the stress of anesthesia. Daily fecal and urine samples were collected from four captive chimpanzees (Pan troglodytes) before and after anesthetizations with Telazol/Ketasat. Tests of assay validity indicated that cortisol was measurable in chimpanzee fecal extracts. Fecal cortisol concentrations were significantly elevated 2 days after anesthetization, with elevations in seven of the eight treatments. The posttreatment peak was significantly greater than baseline values in three of the four subjects. Both fecal concentrations and proportionate increases in responses to stress were significantly correlated with the corresponding values in urinary cortisol, confirming the stressfulness of these procedures and the stress responsiveness of fecal cortisol. These findings provide evidence for the application of fecal cortisol as a noninvasive index of physiologic stress in nonhuman primates.

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Friendships" (ongoing interpersonal interactions) and agitated behavior were studied among 59 residents of a dementia special care unit; most residents had mild to moderate cognitive impairment. Behavior scan data were recorded by trained observers over six months. Three scans per hour were conducted, seven days a week, between 9 a.m. and 9 p.m., producing more than 17,000 observations. A marginal model for binary longitudinal data was developed to associate covariates with repeated observations of agitation, the dependent variable; generalized estimating equations were used to estimate regression parameters. Friendship behavior was significantly associated with (less) observed agitation in this group of dementia residents, controlling for additional variables expected to predict agitation. Opportunity for self-initiated interpersonal engagement may contribute significantly to the wellbeing of moderately impaired dementia residents. Repeated over-time assessments are important in understanding factors related to expression of problem behaviors in this population.Problem behaviors, both physical and verbal, are common among persons with dementing illness. These behaviors are often referred to as expressions of agitation. Nursing home units that are dedicated to 188