Hair cortisol in captive corral-housed baboons.

Area of Science:

• Primate endocrinology
• Animal behavior
• Stress physiology

Background:

• Hair cortisol concentrations (HCCs) are established biomarkers for long-term hypothalamic-pituitary-adrenocortical (HPA) axis activity and chronic stress.
• Intrinsic factors like age and sex are known to influence HCCs, but baseline data in captive baboon populations are limited.
• Understanding these factors is crucial for accurate interpretation of stress levels in research settings.

Purpose of the Study:

• To measure baseline hair cortisol concentrations (HCCs) in captive olive and olive/yellow baboons.
• To assess the impact of age and sex on HCCs in this baboon population.
• To establish reference ranges for HCCs in captive baboons.

Main Methods:

• Hair samples were collected from the nape of the neck of sedated baboons during routine physical examinations.
• Subjects were categorized into three age groups: juvenile (2-4 years), adult (9-12 years), and senior (13-19 years).
• HCCs were analyzed to determine the effects of sex and age, including interactions between these variables.

Main Results:

• Females exhibited significantly higher HCCs than males.
• Juveniles displayed higher HCCs compared to adults.
• A significant sex × age interaction was observed: juvenile HCCs showed no sex difference, but adult males had a greater decline in HCCs than adult females. Within males, juveniles had higher HCCs than adults and seniors.

Conclusions:

• This study provides the first baseline hair cortisol concentrations for captive olive and olive/yellow baboons.
• Both sex and age significantly influence HCCs in this population, with distinct patterns observed between sexes and age groups.
• These findings highlight the importance of considering age and sex when interpreting HCCs as indicators of chronic stress in captive baboons.