Analysis of endogenous cortisol concentrations in the hair of rhesus macaques
Short-term changes in activity of the hypothalamic–pituitary–adrenocortical (HPA) system are routinely assessed by measuring glucocorticoid or metabolite concentrations in plasma, saliva, urine, or feces. However, there are no current methods for determining long-term (i.e., weeks or months) activity of this system. Herein, we describe the development and validation of a simple procedure for measuring cortisol […]
Discrete or graded variation within rhesus monkey screams? Psychophysical experiments on classification
Gouzoules et al. (1984, Animal Behaviour,32, 182-193) presented evidence that semifree-ranging rhesus monkeys, Macaca mulatta, produce acoustically distinctive classes of scream vocalizations that carry different functional messages. To determine the perceptual validity of these vocal classes, we conducted psychophysical experiments on captive rhesus monkeys. We trained two monkeys to maintain contact with a metal response […]
Socially deprived rhesus macaques fail to reconcile: do they not attempt or not accept reconciliation?
Reconciliation, affiliation between opponents after a conflict, is an important means to reduce the detrimental effects of aggression in social primates. Socially deprived (SD) rhesus macaques, Macaca mulatta, however, do not reconcile, while socially raised animals do. This lack of reconciliation in deprived animals may be caused by (1) a lack of secure and valuable […]
In vitro fertilization and embryo transfer technology as an aid to the conservation of endangered primates
Abstract 10.1002/zoo.1430080505.abs Experimental embryological techniques using the rhesus monkey are described. Procedures have been developed for sperm capacitation, in vitro fertilization (IVF), culture of embryos, and embryo transfer. Development of procedures for in vitro oocyte maturation is presently underway. Whereas these procedures are intended to provide basic information about early embryonic development in primates, they […]
Early rearing interacts with temperament and housing to influence the risk for motor stereotypy in rhesus monkeys (Macaca mulatta)
Laboratory and zoo housed non-human primates sometimes exhibit abnormal behaviors that are thought to reflect reduced well-being. Previous research attempted to identify risk factors to aid in the prevention and treatment of these behaviors, and focused on demographic (e.g. sex or age) and experience-related (e.g. single housing or nursery rearing) factors. However, not all animals […]
Quantifying food intake in socially housed monkeys: Social status effects on caloric consumption
Obesity results from a number of factors including socio-environmental influences and rodent models show that several different stressors increase the preference for calorically dense foods leading to an obese phenotype. We present here a non-human primate model using socially housed adult female macaques living in long-term stable groups given access to diets of different caloric […]
Rhesus monkeys (Macaca mulatta) lack expertise in face processing
Faces are salient stimuli for primates that rely predominantly on visual cues for recognizing conspecifics and maintaining social relationships. While previous studies have shown similar face discrimination processes in chimpanzees and humans, data from monkeys are unclear. Therefore, three studies examined face processing in rhesus monkeys using the face inversion effect, a fractured face task, […]
The elffects of control over high intensity noise on plasma cortisol levels in rhesus moneksy.
The effects of control over exposure to high intensity noise on plasma cortisol levels and social behaviors were examined in rhesus monkeys. There were four conditions: control over noise, loss of control over noise, no control over noise, and no noise. Plasma cortisol data indicated that animals with control over high intensity noise stimulation did […]
Short and long-term effects of a substantial change in cage size on individually housed, adult male rhesus monkeys (Macaca mulatta)
We investigated the effects of a six-fold increase in cage size on the behaviour of individually housed male rhesus monkeys. Limitations of previous studies included the magnitude of change in cage size, the length of the observation period, and the potential confounds of relocation. Prior to this study, eight male monkeys were individually housed in […]
Learning capacities of the infant rhesus monkey
Delayed response, patterned string tests and discrimination learning problems administered at intervals during the rhesus monkey’s first year of life show the feasibility of estimating the learning capacity of infant monkeys. Individual discrimination problems were learned at 150 days of age and ability to form learning sets was demonstrated. Delayed responses up to 40 sec. […]