Niche differentiation between coat colour morphs in the Kermode bear (Ursidae) of coastal British Columbia
Bibliographic record
Abstract
One of the most distinctive colour polymorphisms of any mammal occurs in black bears (Ursus americanus kermodei Hornaday) of the Great Bear Rainforest of coastal British Columbia. We use carbon and nitrogen stable isotope values and C/N ratios along segments of hair shafts obtained from 14 white and 12 black individual bears to quantify dietary niche of the morphs as a test of the multi-niche model for a polymorphism. On Gribbell Island, where the white bear reaches 30%, 15N is significantly (GLM repeated measures) more enriched (more marine-derived nitrogen) in the white morph than in the black morph in each season (spring, summer, autumn). On the adjacent Princess Royal Island, where the white morph is less common, both morphs are highly enriched during autumn (~δ15N = +11‰), but there are no isotopic differences between morphs in any season. On both islands, C/N ratios (~3.1) of the black morph decrease from spring to autumn, converging on the lower average values for the white morph. Our data suggest that niche of the white morph involves increased use of a marine-associated diet and that ecological segregation between the morphs has facilitated the historical persistence of the polymorphism.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".