Preliminary Findings on How Different Management Systems and Social Interactions Influence Fecal Glucocorticoid Metabolites in White Rhinoceros (Ceratotherium simum)

Abstract

White rhinoceroses (Ceratotherium simum) are the most social and gregarious species of all rhinoceroses known worldwide. One of the most critical effects of elevated glucocorticoid concentrations, especially in threatened species, is its relation to chronic stress, which could potentially lead to immunosuppression and reduced reproductive activity. Our aim is to determine how different social environments and management systems might be influencing the secretion of fecal glucocorticoids in white rhinoceroses. We have analyzed the concentration of fecal glucocorticoid metabolites in 658 fecal samples from 14 white rhinoceroses, seven free-ranging rhinos, and seven rhinos from two different managed captive populations. HPLC techniques were used to determine the main glucocorticoid metabolite found in this species, and a competitive EIA was used to establish fecal 5α-pregnan-3 3β, 11β, 21-triol-20-oneglucocorticoid metabolite (fGCM) levels. Our results reveal that management systems and social interactions had an influence on fGCM levels, suggesting that the more restrictive the management and social conditions are, the higher the glucocorticoid concentrations that are found. Additionally, sex was also found to influence fGCM levels, as in females, fGCM concentrations were higher than in males. We conclude that the analysis of glucocorticoids in relation to other factors is a powerful tool to assess adrenocortical response in white rhinoceros in order to broaden the knowledge of their reproductive biology and improve the management of the species.

Predicting Sex in White Rhinoceroses: A Statistical Model for Conservation Management

“…The quantification of the fecal EST and TES levels was performed using a competitive EIA that was developed and validated at the Endocrinology Laboratory of the Department of Animal Physiology, Veterinary Faculty, Complutense University of Madrid [15,48]. In summary, similar microtiter plates were coated overnight at 4 A 6957) were prepared by diluting the conjugate stocks in assay buffer.…”

“…Several studies have developed non-invasive techniques (which limit animal disturbance) to determine the hormonal profiles in order to monitor and improve the management of different animal populations, especially in endangered species [7,11,[14][15][16][17]. In the rhinoceros, the biological samples used to perform non-invasive hormone assays are feces, urine, and saliva [16,18,19]; however, when it comes to wild populations, fecal samples are extensively employed and highly convenient, particularly due to their ease of collection and preservation. Fecal-excreted metabolites are vulnerable to bacterial and environmental degradation, but as long as feces is collected relatively soon after defecation, the metabolites present are a reliable indicator of the physiological state [20].…”

Exploring the behaviors and social preferences of a large, multigenerational herd of zoo‐housed southern white rhinoceros (Ceratotherium simum simum)

“…To date, there is evidence that social interactions play a significant role in the well‐being of zoo‐managed SWR (Hutchins & Kreger, 2006; Martínez et al, 2022; L. C. Metrione & Harder, 2011). Fecal glucocorticoid metabolites (fGCM), often used as a metric to assess stress (Sheriff et al, 2011), have been linked to social opportunities and herd composition.…”

“…The fluid social structure of wild SWR is difficult to replicate in zoo settings due to habitat size constraints and individual availability of animals. Few studies have been able to examine how varying zoo management practices affect rhino sociality, especially in large family groups (Cinkova & Bicik, 2013; Martínez et al, 2022).…”

“…To date, there is evidence that social interactions play a significant role in the well-being of zoo-managed SWR (Hutchins & Kreger, 2006;Martínez et al, 2022;L. C. Metrione & Harder, 2011).…”