Title of Poster

Potential Effects of Infanticide Risk on Female American Black Bear Space Use

Name of Conference

International Conference on Bear Research and Management

Location of Conference

Thessaloniki, Greece

Date of Poster Session


Document Type

Poster Session




Social dominance and intraspecific predation have been documented in bear (Ursus spp.) populations. Male bears may increase their fitness by killing unrelated offspring to bring a female into reproductive condition sooner. The ideal despotic distribution model and sex hypothesis of sexual segregation predict adult female American black bears (Ursus americanus) will avoid areas occupied by adult males to reduce risk of infanticide. Home range selection and movement patterns are important aspects of black bear ecology that may be influenced by multiple factors, including risk from other bears. To address the hypothesis that females with cubs exhibit behavior to reduce the risk of infanticide, we compared adult female and adult male locations in Michigan’s Upper Peninsula, USA. We predicted that females with cubs would occupy smaller core areas and home ranges than females without cubs, would occupy core areas and home ranges that had lesser probability of male use than females without cubs, would move shorter distances each day than females without cubs, and would move shorter distances at times of day when males move greater distances. We calculated distance to nearest road and landcover class for each male location. We will estimate probabilistic male use of the study area using generalized linear mixed models (GLMMs). We estimated adult female core areas (50% isopleths) and home ranges (95% isopleths) using fixed kernel density estimators with the solve-the-equation (STE) technique. We will compare probabilistic male use for each female reproductive status (with or without cubs) and isopleth (core area or home range) type using GLMMs. We will compare female core area and home range size by reproductive status using GLMMs. We will compare sex, reproductive status, and diel period by daily movements using GLMMs. If the study results suggest female bear movements and space use are consistent with risk avoidance behavior to reduce infanticide, additional studies to document the extent of infanticide may be warranted

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