Changes in the diet of free-ranging black bears in years of contrasting food availability revealed through milk fatty acids
Bibliographic record
Abstract
We studied patterns of fatty acid signatures in milks and major foods of free-ranging lactating black bears (Ursus americanus) in western Massachusetts to examine the degree to which changes in milk fatty acids could be related to measured changes in food availability and scat analysis, and to assess whether fatty acids could be used to infer aspects of the diets of individuals. Milk samples (n = 45) were obtained from 17 individual bears during years of contrasting hard-mast abundance. Paired winter-den and spring-foraging samples were obtained from females in 1994 (n = 10), 1995 (n = 2), and 1996 (n = 8). In seven of these females, paired den and foraging samples were collected in both 1994 and 1996, representing two consecutive lactation periods. Milk fatty acid patterns indicated that the diet of individuals responded strongly to food availability both prior to denning and during spring foraging. During spring foraging, although females likely continued to mobilize stored fat, the greatest contribution to milk fatty acids appeared to be from dietary fat intake. Hence, qualitative changes in spring diets of individual bears could be reasonably inferred from milk fatty acid signatures. During the year of lowest hard-mast abundance, milk fatty acid patterns suggested that females relied predominantly on a diet of skunk cabbage, although this varied among individuals. This study demonstrates that milk fatty acid signatures can be used to provide insight into the nutritional ecology of bears at the level of the individual.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".