Large carnivores, such as brown bears (Ursus arctos), wolves (Canis lupus), and tigers (Panthera tigris), can play a key ecological role from their apex position in trophic systems. Within the overall context of bottom-up and top-down regulation of ecosystems, predation by large carnivores often induces demographic and behavioral changes in prey species. These vertical interactions between different trophic levels are important regulatory mechanisms in nature. On the other hand, competitive interactions between species, or horizontal interactions within the same trophic level, are also common. Interspecific interactions between large carnivores are widespread in many ecosystems and can play an important role in community structure and stability. Predation is the mechanism driving apex predators’ function in nature, but it is also a source of conflict with different stakeholders, e.g. hunters and livestock owners, when predation affects domestic or semidomestic species (depredation). This situation is challenging when trying to secure long-term carnivore conservation and coexistence with people in the human-dominated landscapes that currently characterize most of our planet.

This chapter comprises the following sections: names, taxonomy, subspecies and distribution, descriptive notes, habitat, movements and home range, activity patterns, feeding ecology, reproduction and growth, behavior, parasites and diseases, status in the wild, and status in captivity.

Humans disturb bears in many ways, either directly when they encounter humans or indirectly by changing their behavior and way of life to avoid humans, human activity, and infrastructure. Here we summarize research on how brown bears normally react when encountering humans, what a human encounter may entail for a bear, and whether bears habituate or change their behavior toward humans with increased exposure. Based on this, we also discuss: (a) how our knowledge of brown bear behavior may help people to deal with their fear of bears, and not limit their use of outdoor areas with bears; (b) how human presence, activity, and infrastructure have an indirect effect on bears, that is, how bears change their movement pattern, use of terrain and vegetation, and daily activity pattern to avoid humans; (c) how human disturbance influence foraging and denning, which is crucial for brown bear growth and reproduction; and (d) apparent differences among continents in brown bear behavior toward humans and whether this may have an evolutionary cause.