Environmental impact on activity level and fecal glucocorticoid metabolite concentration of African elephants and black rhinoceros at brookfield zoo

So far few studies have investigated the impact of season, associated exhibit attendance and ambient sound on zoo animals in general, yet there is increasing public concern that some of these factors may negatively impact zoo animals. A study on giant pandas at the San Diego Zoo Owen at el.1 investigated the impact of sound on adrenal and behavioral indicators of stress and found that louder sound was associated with an increase of stress-related behaviors, such as vocalization, door scratching, increased locomotion, and/or increased urinary glucocorticoid levels in all study animals. Carlstead at al.2 found higher fecal glucocorticoid levels (FGM) in black rhinoceros housed in enclosures with a greater portion of the perimeter accessible to visitors. Two other studies, one on orangutans at Chester Zoo, UK, Birke et al.3 and the other on black rhinoceros at various US zoos Carlstead4,5 also documented an increase in some behaviors associated with higher levels of stress when larger groups of people were present and/or sound levels were higher. Black rhinoceros showed an increase in fear-related behavior traits such as shyness and anxiety. Unfortunately, the two latter studies were not able to assess physiological indicators in addition to behavioral assessments. Combining more than one potential indicator when looking for increased stress responses is key to better understanding the impact of various factors on an individual’s welfare Wielebnowski.6 The growing availability of reliable non-invasive measurement techniques, such as FGM monitoring, makes longitudinal studies using physiological indicators in combination with behavioral observations increasingly feasible Möstl & Palme,7 Millspaugh & Washburn.8