Boyle Sarah A, Roberts Beth, Pope Brittany M, Blake Margaret R, Leavelle Stephen E, Marshall Jennifer J, Smith Andrew, Hadicke Amanda, Falcone Josephine F, Knott Katrina, Kouba Andrew J
Department of Biology, Rhodes College, Memphis, Tennessee, United States of America.
Conservation and Research Department, Memphis Zoological Society, Memphis, Tennessee, United States of America.
PLoS One. 2015 Nov 4;10(11):e0141009. doi: 10.1371/journal.pone.0141009. eCollection 2015.
Captive African (Loxodonta africana) and Asian (Elephas maximus) elephants can experience foot pathologies and arthritis. As a preventative measure against these pathologies and to alleviate the potential discomfort due to concrete substrates, some zoological institutions have renovated elephant housing to increase the amount of natural or shock-absorbent substrates. The objective of this study was to compare behavioral (diurnal and nocturnal) and glucorticoid (e.g., serum cortisol) responses of three female African elephants before, during, and after renovation to their indoor housing floor to assess whether renovations had short-term effects on the elephants' behavior and stress physiology. Behavioral data were collected using scan-sampling methods, and activity budgets were constructed for each of the three elephants. In addition, the duration of all lying rest activities were recorded. Weekly serum cortisol concentrations were determined with enzyme immunoassay (EIA). Overall, eating was the most prevalent behavior exhibited outdoors during the day, while resting (either in a lying or standing position) were most common during the indoor, nocturnal periods. Although variation existed among the three elephants, all three females spent significantly more time walking and less time eating during the day after the completion of the renovations. The extent to which the three elephants exhibited nocturnal lying rest behavior varied among the elephants, with the oldest elephant exhibiting the least amount (an average of 13.2 ± 2.8% of the nightly behavioral scans) compared to the two younger elephants (an average of 34.5 ± 2.1% and 56.6 ± 2.8% of the nightly behavioral scans). There was a significant increase in lying rest behavior for one elephant and standing rest for a second elephant following renovations. Baseline cortisol concentrations prior to renovations were 3.0 ± 0.4 ng/ml, 4.5 ± 0.5 ng/ml, and 4.9 ± 0.5 ng/ml for the three elephants. Cortisol concentrations remained baseline for two of the elephants throughout and after the renovation period, while one elephant that was pregnant had elevated cortisol during construction. Cortisol concentrations for the pregnant elephant remained higher than baseline once she was introduced to the new flooring and allowed back into the building, but these values were closer to the cortisol concentrations before renovations than during construction. Our findings demonstrate that individual elephants can vary in their behavioral and physiological responses to exhibit modifications. Given that the elephants walked more during the day, two of the three elephants had an increase in rest behavior during the night, and there were minimal changes in cortisol response after the flooring renovations, we conclude that the flooring renovations overall had a positive impact on animal welfare.
圈养的非洲象(非洲象属)和亚洲象(亚洲象)会出现足部病变和关节炎。作为预防这些病变的措施,并缓解因混凝土地面导致的潜在不适,一些动物园对大象的圈舍进行了翻新,以增加天然或减震地面材料的用量。本研究的目的是比较三头雌性非洲象在室内圈舍地面翻新前、翻新期间和翻新后的行为(昼夜)和糖皮质激素(如血清皮质醇)反应,以评估翻新是否对大象的行为和应激生理产生短期影响。行为数据采用扫描取样法收集,并为三头大象分别构建了活动预算。此外,还记录了所有躺卧休息活动的时长。每周通过酶免疫测定法(EIA)测定血清皮质醇浓度。总体而言,白天在户外时,进食是最普遍的行为,而在室内夜间时段,休息(躺卧或站立)最为常见。虽然三头大象之间存在差异,但在翻新完成后的白天,所有三头雌性大象行走的时间显著增加,进食的时间减少。三头大象夜间躺卧休息行为的表现程度各不相同,年龄最大的大象表现出的躺卧休息行为最少(平均占夜间行为扫描的13.2±2.8%),而另外两头较年轻的大象则较多(平均分别占夜间行为扫描的34.5±2.1%和56.6±2.8%)。翻新后,一头大象的躺卧休息行为显著增加,另一头大象的站立休息行为增加。翻新前,三头大象的皮质醇基线浓度分别为3.0±0.4 ng/ml、4.5±0.5 ng/ml和4.9±0.5 ng/ml。在翻新期间及之后,其中两头大象的皮质醇浓度一直保持在基线水平,而一头怀孕的大象在施工期间皮质醇水平升高。当这头怀孕的大象被引入新地面并被允许回到圈舍后,其皮质醇浓度仍高于基线水平,但这些值比施工期间更接近翻新前的皮质醇浓度。我们的研究结果表明,个体大象对环境变化的行为和生理反应可能存在差异。鉴于大象在白天行走更多,三头大象中有两头在夜间的休息行为增加,并且地面翻新后皮质醇反应变化不大,我们得出结论,总体而言,地面翻新对动物福利产生了积极影响。