New Biomarkers to Better Perform Welfare Assessment on Wild Animals

An article presents a major advance in the welfare assessment of animals in both wildlife and captive populations. It promotes more accurate, non-invasive biomedical methods to anticipate physiological stress and prevent zoonoses as well as impacts on biodiversity.  

Toward a More Refined Welfare Assessment

Traditionally, the well-being of wild species has been measured using behavioral or hormonal indicators (such as cortisol). The authors of the editorial question the validity of these isolated biomarkers, which are often generalized without taking into account species, age, sex, or environmental context. They advocate for a systemic approach that integrates multiple physiological parameters (fecal thyroid hormones, heart rate variability, markers of oxidative stress, metabolic enzymes) to detect subtle changes in well-being before they become chronic.  

Species-Specific Biomarkers

The authors emphasize the need to adapt and validate methods on a case-by-case basis, depending on the species being studied. For example, thyroid hormone levels measured in feces can vary depending on the season, the animals’ health status, or the environment. These fluctuations, observed in several wild animals, require that normal thresholds be calibrated according to the individual or ecological context. Similarly, the combined analysis of enzymes such as creatine kinase, lipid metabolites, and markers of oxidative stress provides a more meaningful physiological picture, revealing reduced activity, immune dysfunction, or chronic stress before the onset of visible clinical signs.  

Advances for Public Health and Wildlife

Such precision in the welfare assessment of wild animals is doubly beneficial. It improves the conservation of vulnerable species by rapidly identifying stressors related to captivity, pollution, or relocation. It also reduces zoonotic risks: a stressed or immunocompromised animal is more likely to become a reservoir for pathogens transmissible to humans. By incorporating markers such as the gut microbiota or early hormonal responses, these tests make it possible to anticipate the onset of diseases or inflammatory reactions before clinical symptoms develop.  

The Rise of Innovative “Omics” and Biomedical Techniques

The editorial highlights the growing role of so-called “omics” techniques (metagenomics, metabolomics, lipidomics) in this methodological evolution. By combining molecular, behavioral, and environmental data, it becomes possible to construct individual or collective animal health profiles tailored to each species. Noninvasive approaches (fecal collection, urine samples, thermographic analyses, and heart rate variability measurements) allow for repeated assessments without the need for capture, thereby minimizing the stress associated with the procedure itself.   The article advocates for this new shift: moving from a single visual assessment to validated biomolecular diagnostics. This new scientific advancement improves the precision of veterinary interventions, reintroduction programs, and assessments of captive animals.