The importance of measuring stress in hedgehogs and how a new method could enhance welfare

Determining when a hedgehog is stressed can be achieved through a new non-invasive method discovered by Ph.D. researcher Emily Harper. By analyzing hormones in hedgehog feces, researchers can now understand how different stressors impact the health and welfare of these declining species. This validated method, published in Conservation Physiology, allows for the study of stress responses both in the wild and during rehabilitation.

Stress is a natural response to danger, helping animals react quickly when threatened. However, prolonged stress can lead to chronic issues such as reduced immunity, reproductive complications, and increased mortality rates. For vulnerable species like the European hedgehog, identifying stress causes is crucial for conservation efforts.

Hedgehogs, as indicator species, provide insights into overall ecosystem health and are the most rescued mammals in the U.K., with around 40,000 in captivity at any given time. Measuring stress in hedgehogs can also improve their welfare during rehabilitation, allowing assessment of treatments, captivity impacts, and post-release recovery.

The research tests three noninvasive assays commonly used in other mammals to measure stress in hedgehogs. All three assays successfully detected relevant changes in glucocorticoid levels following a stressor, with one assay being the most sensitive. Upon admission to rehabilitation, hedgehog glucocorticoid levels peaked on the first day and decreased seven days later.

Hedgehogs admitted to rehabilitation that died had significantly higher glucocorticoid levels than survivors, and those infected with Capillaria also showed higher levels. After seven days in rehabilitation, glucocorticoid levels returned to levels seen in wild, uninfected hedgehogs.

With a validated stress measurement method for European hedgehogs, future research can explore the effects of various stressors, such as habitat changes and human activities, on hedgehog populations. This new approach can also enhance welfare in rehabilitation settings by enabling the assessment of treatment impacts, captivity effects, and specific injuries or diseases to monitor hedgehog welfare during and after release.