Frustrated Appetitive Foraging Behavior, Stereotypic Pacing, and Fecal Glucocorticoid Levels in Snow Leopards (Uncia uncia) in the Zurich Zoo

This study hypothesized that permanently frustrated, appetitive-foraging behavior caused the stereotypic pacing regularly observed in captive carnivores. Using 2 adult female snow leopards (Uncia uncia), solitarily housed in the Zurich Zoo, the study tested this hypothesis experimentally with a novel feeding method: electronically controlled, time-regulated feeding boxes. The expected result of employing this active foraging […]

Aggressive behaviour traits predict physiological stress responses in Nile tilapia (Oreochromis niloticus)

This study tested whether aggressive behaviour can predict individual variation in stress responses of Nile tilapia Oreochromis niloticus.We used a mirror test to measure tendency to aggressive behaviour, and calculated the attack frequency and time until the first attack (latency) for each fish. One day later, we measured plasma cortisol and glucose, and two days […]

Do baseline glucocorticoids predict fitness?

Baseline glucocorticoid (cort) levels are increasingly employed as physiological indices of the relative condition or health of individuals and populations. Often, high cort levels are assumed to indicate an individual or population in poor condition and with low relative fitness (the Cort–Fitness Hypothesis). We review empirical support for this assumption, and find that variation in […]

Zoo Research Guidelines: Monitoring Stress in Zoo Animals


Stress hormones and mate choice

A few recent studies have suggested that glucocorticoid stress hormones can play a role in sexual selection. In terms of mate choice, these studies have shown that individuals can exhibit preferences for mates with either low baseline or peak glucocorticoid levels. This appears to occur because stress hormones can be key mediators of many condition-dependent, […]

Association of glucocorticoid with stress-induced modulation of body temperature, blood glucose and innate immunity

To know the details of the mechanism on stress-associated responses, attention was first focused on body temperature and blood glucose after stress. Mice were exposed to restraint stress for 6 h. Under this condition, hypothermia (39 °C → 33 °C) and hyperglycemia (150 mg/dl → 350 mg/dl) were induced. Reflecting a stress-associated response, an increase […]

Hormones as indicators of stress

Animal welfare is of increasing importance and absence of chronic stress is one of its prerequisites. During stress, various endocrine responses are involved to improve the fitness of the individual. The front-line hormones to overcome stressful situations are the glucocorticoids and catecholamines. These hormones are determined as a parameter of adrenal activity and thus of […]

Does corticosterone mediate bidirectional interactions between social behaviour and blood parasites in the juvenile black iguana, Ctenosaura similis?

Complex bidirectional interactions between host social behaviour and infectious organisms (parasites) can be mediated by alterations in host glucocorticoid [`]stress’ hormones. As a result, an animal’s social behaviour may affect its susceptibility to parasitism, and its infection status may influence its social behaviour. Our field study of behaviour, hormones and parasites in free-living juvenile male […]

The subordination stress paradigm and the relation between testosterone and corticosterone in male ring-necked pheasants

The relations linking glucocorticoids, testosterone, social and sexual behaviour in vertebrates are complex and poorly understood. The conventional view is that: (1) subordinate individuals should have higher glucocorticoid concentrations (the subordination stress paradigm); (2) dominant and more active males during the breeding season should have higher testosterone concentrations; and (3) the relation between glucocorticoid and […]

Effect of acute stress on plasma concentrations of sex and stress hormones in juvenile alligators living in control and contaminated lakes

Environmental contaminants can act as stressors, inducing elevated circulating concentrations of stress hormones such as corticosterone and cortisol. Development in contaminated eggs has been reported to modify circulating sex steroid hormone concentrations in alligators (Alligator mississippiensis). We examined plasma concentrations of testosterone (T), estradiol-17β (E2), and corticosterone (B) immediately upon and two hours after capture […]