Why do Amur tigers maintain exclusive home ranges? Relating ungulate seasonal movements to tiger spatial organization in the Russian Far East



Cheryl E. Hojnowski, 900 Mendocino Ave. Apt B, Berkeley, CA 94707, USA. Tel: +1 510 725 1879

Email: cherylhojnowski@gmail.com


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 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.