Factors Influencing Body Condition in Cabinet-Yaak Ecosystem Black Bears

• Main Author: Schwartzkopf, Caleb M
• Format: Text
• Language: unknown
• Published: ScholarWorks at University of Montana 2017
• Subjects: Ursus arctos
• Online Access: https://scholarworks.umt.edu/umcur/2017/amposters/15; https://scholarworks.umt.edu/context/umcur/article/1868/viewcontent/ThesisPoster_CalebS.pdf

Grizzly bears (Ursus arctos) are a species on recovery. This holds true for the bears in the Cabinet-Yaak ecosystem. Low reproductive rates make recovery especially difficult for this species. These rates are affected by body condition, which has been found to predict reproductive success, both for grizzly and black bears (Ursus americanus). So what is it that affects body condition in bears? We sought to answer this question by using research collected from black bears in this region. We analyzed several different variables, which included: vegetation and berry production, hunter harvest estimates, winter temperatures, age, and body metrics (i.e. weight, girth, shoulder height, etc.). We found that during the first half of the summer, body fat content of a bear is most strongly related to body metrics, such as weight. This changes for the second half of their year, in which current year vegetation production and previous year deer gut piles left by hunters become more important. These results indicate that during the first half of the year, the energy consumed is put towards growth (for young bears) and building lean body mass. The second half of the year is more crucial for building fat reserves. It is during this time of year that bears enter into hyperphagia, a state of prodigious eating where they prepare for hibernation.