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State-dependent foraging by caribou with different nutritional requirements.
Kristin Denryter1,2, Rachel C Cook3, John G Cook3
1Natural Resources and Environmental Studies, University of Northern British Columbia, Prince George, British Columbia, Canada.
Journal of Mammalogy
|May 27, 2020
Summary
Caribou foraging behavior is state-dependent, varying with nutritional needs. Lactating caribou forage longer daily, indicating physiological state influences their foraging strategies.
Area of Science:
- Animal Behavior
- Ecology
- Physiology
Background:
- Animal foraging is hypothesized to be state-dependent, influenced by individual physiological condition and nutritional requirements.
- Testing state-dependent foraging in ungulates is challenging due to a lack of fine-scale behavioral data.
Purpose of the Study:
- To evaluate whether foraging in caribou (Rangifer tarandus) is state-dependent.
- To compare foraging behaviors across caribou with differing nutritional requirements: lactating adults, nonlactating adults, and subadults.
Main Methods:
- Compared bite and intake rates, travel rates, dietary quality, forage selection, daily foraging time, and foraging strategies.
- Analyzed data from caribou with three distinct nutritional requirement levels.
Main Results:
- Only daily foraging times and daily nutrient intakes differed significantly among nutritional classes.
- Lactating caribou exhibited longer daily foraging times than nonlactating caribou, a difference most pronounced at high intake rates.
- Caribou continued foraging even after meeting daily nutritional requirements, suggesting an energy maximization strategy.
Conclusions:
- Caribou foraging time is partially state-dependent, emphasizing the need to consider physiological state in behavioral studies.
- Fine-scale foraging behaviors can impact larger-scale strategies, with implications for caribou conservation and management.
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