Proximity to humans is associated with longer maternal care in brown bears
In the sexual conflict over the duration of maternal care, male mammals may improve their reproductive success by forcing early mother–offspring separation in species where lactation supresses estrus. However, when individual females benefit from continuing to care for their current offspring, they should adopt counter-strategies to avoid separation from offspring. Here, we tested whether spatial segregation from adult males and proximity to humans during the mating season could be associated with longer maternal care in the Scandinavian brown bear (Ursus arctos). Using resource selection functions (RSFs), we contrasted habitat selection patterns of adult males and those of adult females with yearlings that either provided 1.5 years of maternal care (“short-care females”) or continued care for an additional year (“long-care females”) during the mating season, the period when family break-ups typically occur. Males and short-care females had similar habitat selection patterns during the mating season. In contrast, habitat selection patterns differed between males and long-care females, suggesting spatial segregation between the two groups. In particular, long-care females used areas closer to human habitations compared with random locations (defined here as selection), whereas males used areas further to human habitations compared with random locations (defined here as avoidance). Our results show a correlation between habitat selection behavior and the duration of maternal care. We suggest that proximity to humans during the mating season may represent a female tactic to avoid adverse interactions with males that may lead to early weaning of offspring.
In mammalian species where lactation supresses ovulation, males may gain a reproductive advantage by forcing early mother-offspring separation; however females can respond through behavioral tactics. We show that female brown bears with yearling cubs can spatially segregate from males during the mating season and that this behavior is associated with longer maternal care. Females selecting areas close to human habitations tend to keep their yearlings for an additional year, suggesting that human presence could have a shielding effect from males. Our study is among the few to explore sexual conflicts over the duration of maternal care close to weaning and shows that animals have the potential to adjust their behavioral tactics to make use of human-dominated landscapes.
KeywordsSexual conflict Maternal care Spatial segregation Brown bear
We thank A. B. Scarpitta for his advice on the multivariate analyses. We are grateful to M. Festa-Bianchet, the associate editor and two anonymous reviewers for their comments on the manuscript. We are also grateful for the support of the Quebec Centre for Biodiversity Science. This is scientific paper number 285 from the Scandinavian Brown Bear Research Project.
JVdW and ML were financially supported by the Natural Sciences and Engineering Research Council of Canada (NSERC). FP was funded by NSERC discovery grant and by the Canada Research Chair in Evolutionary Demography and Conservation. The Scandinavian Brown Bear Research Project is funded by the Swedish Environmental Protection Agency, the Norwegian Directorate for Nature Management, the Austrian Science Fund, and the Swedish Association for Hunting and Wildlife Management.
Compliance with ethical standards
Our use of animals followed all applicable national guidelines. Our handling of study animals was approved by the appropriate authorities and ethical committee: the Swedish Board of Agriculture (no. 35-846/03, 31-7885/07, 31-11102/12), the Uppsala Ethical Committee on Animal Experiments (no. C40/3, C47/9, C7/12), and the Swedish Environmental Protection Agency (no. 412-7327-09 Nv).
Conflict of interest
The authors declare that they have no conflict of interest.
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