Prey cortisol affects the usefulness of fecal glucocorticoid metabolite concentration as an indicator of stress in a carnivore
Bibliographic record
Abstract
The noninvasive nature of sample collection makes analysis of fecal hormone concentrations useful for examining endocrine responses in free-living wild animals. Glucocorticoid hormones (i.e., cortisol and corticosterone) are frequently measured as an indicator of activation of the endocrine stress axis. However, many factors may influence glucocorticoid concentrations in feces, and the influence of prey glucocorticoids on concentrations in the feces of predators is rarely considered. We tested whether cortisol consumption influenced concentrations of glucocorticoid metabolites in feces of captive Arctic foxes (Vulpes lagopus (Linnaeus, 1758)) by adding cortisol (5 mg cortisol per kg fox body mass) to the foxes’ diet. Food supplemented with supraphysiological concentrations of cortisol increased fecal glucocorticoid metabolite concentrations of Arctic foxes by 97% in males and 51% in females, compared with controls. In addition, fecal metabolite concentrations in nontreatment samples were higher for females (22.2 ± 3.3 ng·g−1, mean ± SE) than males (13.3 ± 1.5 ng·g−1), suggesting female Arctic foxes may have higher baseline cortisol concentrations or females may be more sensitive to captivity or relocation. These results indicate that prey cortisol can influence measurement of glucocorticoid metabolites in carnivore feces and suggest caution may be needed when interpreting such measurements in wild carnivores.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".