This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Monkeys that are housed in captive environments, particularly in individual cages, are at risk for developing abnormal behavior and for showing other potentially detrimental conditions (e.g., alopecia). Alopecia is a perplexing problem in captive nonhuman primates and the pervasive view is that its presence is related to stress. The cycle of hair growth can be disrupted in at least two ways to produce alopecia. However, as we show, there are many factors that may be related to hair loss. These range from naturally occurring processes such as seasonality and aging to various biological dysfunctions including vitamin and mineral imbalances, endocrine disorders, immunological diseases, and genetic mutations. Other causal factors include bacterial and fungal infections, infestation by ectoparasites, and atopic dermatitis. There are also psychogenic factors that may lead to hair loss including behavior disorders (hair plucking) and exposure to stress. Alopecia in nonhuman primates is a multifaceted disorder with many potential sources therefore requiring distinctly different treatments. Appropriate testing for various disease conditions should be carried out before instances of alopecia are assumed to be stress-related.