Validation of 22-sodium to estimate food intake of bears
Farley SD and Robbins CT. 1997. Validation of 22-sodium to estimate food intake of bears. The Journal of Wildlife Management. 61(1):52-56
We measured the turnover of exchangeable sodium in black bears (Ursus americanus) and grizzly bears (U. arctos horribilis) with ${}^{22}\text{sodium}$ $({}^{22}\text{Na})$ and tested the procedure for its usefulness as a predictor of food intake. Sodium excretion had a strong, positive correlation with sodium intake (r2=0.97; SEE = 3.8). 22Na equilibrated with the exchangeable Na pool within 105 minutes (t = 1.844, P < 0.05), and sodium flux was linearly related to sodium intake (r2=0.87; SEE = 10.5). Diets with sodium contents greater than 5 mg Na/g dry matter (DM), between 2 and 5 mg Na/g DM, and less than 2 mg Na/g DM induced biological half-lives of sodium of 8.8 ± 2.5, 19.3 ± 3.5, and 70.5 ± 25.0 days, respectively. Sodium flux rates greater than 75 mg/kg-day and sample sizes of 5-10 animals are required to reduce the error of predicting food intake to less than 10%. This technique is suited for bears consuming primarily meat diets (i.e., winter kill carrion, neonatal ungulates, or spawning salmonids).
- Type
- Journal Article
- Authors
- Farley, Sean; Robbins, Charles
- Units
- YELL
- Keywords
- 22-sodium, Animal Studies, Diet, Ecology, Food intake, IAR, Management