While hair analysis has become routine in humans – for example for the detection of prolonged drug or medication abuse – it has been little used in animals to date. Scientists led by Alexandre Azevedo and Katarina Jewgenow of the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) have now demonstrated that the "stress" hormone cortisol is deposited in hair of wild mongooses in Portugal and determined baselines for cortisol in these carnivores. Age, sex and storage time of the samples were reflected in the cortisol values, but not the season or reproductive status of the females. It is now possible to investigate whether different habitats and changed living conditions, such as the return of the Iberian lynx, place a particular burden on the mongooses. The results were recently published in the scientific journal "PLoS ONE".