Assessing pain and suffering in wild animals is methodologically challenging but scientifically tractable. Advances in behavioral and physiological tools are improving our ability to detect and respond to animal suffering in nature.
For most of history, wild animal pain went unrecognized and unaddressed — partly from methodological limitations and partly from the assumption that welfare concerns applied only to captive animals. Species-appropriate grimace scales (measuring facial action units associated with pain), validated for mice, rats, rabbits, horses, and others, are being adapted for wild species. Fecal glucocorticoid metabolite analysis enables population-level stress monitoring without capture. These tools are shifting wild animal welfare from aspiration to science.