Comparing the Relationship Between Litter size and Cub Weight in American Black Bears ( Ursus americanus )
Nikki Pinter (Not Pictured)
Adrienne Cohoon Wildlife Ecology and Management
Wildlife Ecology and Management
The relationship between reproductive traits within mammalian taxa varies and understanding their relationships can help inform management and conservation. Current understandings of large mammal reproductive strategies show a decreased litter size and trade-offs between litter size and offspring weight. This study analyses the effect of litter size on cub weight in North American black bears ( Ursus americanus ) from the Stephens Family Foundation Wisconsin Black Bear Research Project. We compared litter size and cub weight from 148 litters from 1993 to 2023. We predicted that cub weight would decrease with an increase in litter size. We calculated the cubs ages using the hair lengths between their ears then applied a series of linear regression models to evaluate the relationship between litter size and cub weight with respect to their age. Litters ranged from one to four cubs with an average of 2.9 cubs per litter. Cub weight ranged from 1.25 to 8.5 pounds with an average of 4.65 pounds. Cubs ranged in age from seven to seventy days old at an average of 42.3 days old. The results of our linear regression models were not statistically significant (P=0.325).?Factors such as maternal age, mother’s body condition, or habitat could be confounding the main effect that litter size has on cub weight. These findings go against our typical understanding of large mammal reproductive strategies and highlight the need for future studies of reproductive metrics to monitor the effects of environmental factors on offspring health and growth.
Advisors: Cady Sartini, Ph.D.
Subject Area: Wildlife
Type: Poster
45
UW-Stevens Point College of Natural Resources
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