Fecal Cortisol Dynamics of Captive Giraffes in Zoos in Northern Japan

Animals in zoos are kept under environmental conditions differing from those of their original habitat. Recently, zoos have been attempting to reduce stress by introducing environmental enrichment. Adrenal-derived glucocorticoids are common stress indicators found in blood, saliva, urine, and feces. Fecal cortisol levels have been studied as a stress marker in captive giraffes, but the data are insufficient. In this study, we examined fecal cortisol in captive giraffes in northern Japan to increase basic data on fecal cortisol as an indicator of environmental enrichment. For one month, we collected fecal samples from 14 giraffes [Masai giraffes (Giraffa camelopardalis tippelskirchi) and reticulated giraffes (Giraffa camelopardalis reticulata)] from eight zoos. The fecal samples were stored at –20 °C until fecal cortisol levels were measured using a cortisol EIA kit after drying, grinding, and ethanol extraction. Cortisol levels were compared between males and females, pregnant and nonpregnant animals, by age, and by differences in temperature of the rearing environment. The fecal cortisol levels ranged from 37~10346 pg/g. Among females, pregnant individuals had the highest values. Among nonpregnant females, a female that was harassed by a male had higher fecal cortisol levels than the others. This may be due to chronic psychological distress. In males, values varied greatly among individuals. This study increases the volume of giraffe fecal cortisol data, which will contribute to establishing basic giraffe fecal cortisol values.