Objectives

2

The mechanism of alopecia occurring in 2 species of captive primates was studied to solve the problems of the frequent alopecia

unsatisfactory effects of conventional interventions and unknown core inducements in captive primates

to provide references for the comprehensive prevention and control of alopecia in primates in zoos.

Methods

2

A 4-year-old male eastern hoolock leuconedys with a body weight of 6.3±0.6 kg and a target 7-year-old male sapajus apella with a body weight of 4.1±0.4 kg was divided into a gibbon single-housing group and a capuchin social-housing group. The observation period lasted from February 2025 to April 2026 (15 months). The enclosure temperature and humidity

alopecia grade

frequency of stereotyped behavior

and skin pathogen-related indexes were measured. A grouping-isolation-regrouping controlled trial for capuchins and a winter warming intervention for gibbons were observed based on analyzing the nutritional composition in diet.

Results

2

Cold stress was the primary cause for the alopecia in gibbons with an incidence of 75.00% at temperatures less than 10 ℃

belonging to the environment-stress type which cold stimuli might activate the HPA axis and affect the hair follicle cycle. For capuchins

social psychological stress was the core factor

with spontaneous recovery during isolation and immediate relapse upon regrouping

high temperature coupled with high humidity synergistically exacerbated hair loss (alopecia-record days in summer accounted for 81.82%)

belonging to the composite psychological-stress type

accompanied by stereotypic plucking behavior. Ectoparasites

fungi and nutritional deficiency were excluded as primary causes of the alopecia in the 2 animals.

Staphylococcus

spp. was only a secondary infection.

Conclusions

2

The essence of both types of alopecia may be endocrine disruption and follicular cycle abnormalities caused by stressors. Implementing a strategy of comprehensive prevention and control including the separate housing

precise control of temperature

management of stress

fortification of nutrition

disease intervention

and emotional enrichment can help block the pathway of behavioral stress and reduce the incidence of alopecia in captive primates.