M.S. was supported by an NSF Graduate Cyclopamine Research Fellowship. Funding for fieldwork was provided by grants to M.S. from the American Society of Mammalogists, Chester Zoo, Columbus Zoo, the Explorer’s Club, Minnesota Zoo, Riverbanks Zoo and Garden, and by the University of Minnesota’s Graduate School, GPS Alliance and Bell Museum. We are grateful to Eric Thrane, Sara Cairns and an anonymous reviewer for insightful comments on earlier drafts of the

paper. Figure S1. Male giraffes displaying a classic alert posture after detecting lions nearby. This vigilance behavior is usually accompanied by the suspension of foraging or other activities. Giraffes will turn to gaze at nearby lions, and some individuals may advance toward predators for a closer look (Dagg & Foster, 1982). This behavior is observed in solitary individuals as well as members of single-sexed

and mix-sexed herds. However, not all individuals in a herd will assume an alert posture, and some may seem indifferent to lions (Mejia, in Moss, 1982; Strauss, unpubl. data). Photograph taken in Serengeti National Park by P. Jigsved. “
“Wild, solitary felids demonstrate a variety of spacing patterns, with diversity in spatial organization largely attributed to variations in abundance and distribution of important resources, particularly prey. We examined the relationship between territoriality of female Amur tigers Panthera tigris altaica and seasonal movements of a key prey species, Manchurian red deer see more MCE公司 Cervus canadensis xanthopygus, in the Russian Far East. We predicted that despite considerable seasonal fluctuations in productivity, red deer density does not change seasonally within tigress home ranges. We analyzed radio-telemetry data to identify directional movements of deer as an indicator of relative changes in

seasonal red deer abundance and distribution, and we looked for seasonal shifts in home ranges of tigresses that could signify tracking of migratory prey. We failed to detect either seasonal shifts in tigress home ranges or significant differences in seasonal prey abundance. Most red deer were sedentary, while those that migrated demonstrated varying directionality of movements. Relatively low average snow depth likely reduced directional migratory tendencies in prey populations. Despite existing theory that might predict high overlap of Amur tiger home ranges, our results suggest that exclusive spacing patterns in this tiger subspecies are at least partly explained by the absence of major spatial and temporal changes in ungulate abundance and distribution. We submit that the assumption that home-range overlap should increase with increasing home-range size may require further evaluation in cases such as that of Amur tigers. “
“Species assemblages commonly include species persisting at low density alongside more abundant species, raising questions about the mechanisms enabling this coexistence.