Urine urea-creatinine ratio of mammalian carnivores: a good nutritional index for the wrong reason?
Bibliographic record
Abstract
Urine urea-creatinine ratio (U:C) often is used as an index of nutritional status of wild mammals, especially because urine can be collected from snow, providing a non-invasive index of nutrition. The rate of creatinine excretion has been assumed to be relatively stable; thus, creatinine concentration is used to normalize urea concentrations and control for dilution in snow. We present data from captive wolves (Canis lupus) to test how much variation in U:C is due to variation in urea vs. creatinine in relation to time since feeding. We found that U:C increases for ∼18 hours post-feeding but that this variation is primarily due to the 5-fold decrease in creatinine rather than the 2-fold increase in urea concentration. It is not clear what governs the variable creatinine concentrations in urine. Until a fuller understanding of this metabolite is achieved, ecological studies employing this nutritional index should report urea and creatinine values as well as the ratio. Physiological studies should explore the causes of variation in creatinine concentrations in urine.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.003 | 0.007 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".