El experimento lo llevó adelante un investigador del Conicet en el Museo de Zoología de Vertebrados de la Universidad de California donde está alojada la única población cautiva del tuco-tuco colonial...

Addressing environmental challenges requires scientific collaboration, access to resources, and open knowledge exchange. However, possessive behaviors…

Background Cortisol is often considered an indicator of stress. However, it is not a straightforward indicator of stress in animals and is more closely linked to arousal and hypothalamic-pituitary-adrenal axis (HPA) axis activation. To better understand what animals are experiencing, other stressors, e.g., donkeys carrying heavy loads and being beaten, should be considered when interpreting cortisol levels. Our research aimed to assess how carrying mounted loads and working in challenging conditions impact donkey hair cortisol concentrations (HCC). For this purpose, thirty-five working donkeys were used. Data on the percent body weight ratio (%BWR) carried, the presence of skin wounds and lameness, provision of food and water, mounted load type, whether donkeys were beaten during work, and their working area were collected. Donkey hair samples were analyzed for HCC using an enzyme-linked immunosorbent assay (ELISA) kit and a multispectral plate reader. A multiple linear regression model was fitted to the data by stepwise backward elimination of variables. Results Donkeys were used for carrying fodder (n = 18; 51.4%) and bricks (n = 17; 48.6%) on their backs. Over half of the donkey owners provided water (54.3%, n = 19), and just under half provided food access (45.7%, n = 16) during the working day. The median HCC and %BWR were 4.34 pg/mg (interquartile range [IQR] 3.46–6.27 pg/mg) and 70.77% (IQR 57.0– 85.12%), respectively. Overall, 88.57% of donkeys carried loads above 50% BWR. High %BWR (estimate = 0.04, t = 2.75, p < 0.001), being beaten while working (estimate = 1.60, t = 4.49, p < 0.001), and carrying bricks (estimate = 0.96, t = 2.14, p = 0.04) were predictors of high HCC. Conclusion Carrying heavy loads of bricks and being beaten while working are likely stressful and can lead to increased activity of the HPA, resulting in higher levels of hair cortisol. Hair cortisol measurement is a valuable tool for assessing chronic stress in donkeys. Further research is necessary to assess HCC in donkeys working in different industries, such as mining, cart pulling, field plowing, and modern farming for hides and dairy products, to determine the relationship between cortisol, chronic stress, and the lives of animals.

Our study illustrates a framework for using bird movement data to provide insights into avian behaviour and the risk they encounter around power line infrastructure. Electricity delivery industries c....

Visualising how the climate has changed for every country across the globe

Spiders are excellent subjects for studying sensory detection, cognition, and perception - the central topics of this 2025 Thomas Henry Huxley Review by Prof. Ximena Nelson, based at the University o...