Spatial Organization of Wild Boar (Sus scrofa ussuricus) Associations under the Impact of the Tiger (Panthera tigris altaica) in the Central Sikhote-Alin Mountains, Russian Far East

In the central Sikhote-Alin Mountains, tigers prey mainly on underyearlings and adult female wild boars (67–74% of the total number of prey of this species). In key plots (≥10–15 km2) in the Sikhote-Alin Nature Reserve, (a) wild boar encounters and their tracks in the network of routes were recorded; (b) wild boar snow tracking was conducted; and (c) tiger encounters and snow tracking were recorded (114 episodes). We obtained 16 movement patterns of wild boar groups using snow tracking. Snow tracking of each wild boar group took six to 23 days. Many maternal groups occupied a position central in relation to other accompanying groups (up to eight) and individuals (up to 15) moving in the vicinity, usually over an area (1.5–9.4 km2 or more) that was 1.1–2.2 or more times larger than the area of the maternal group under normal conditions. Such a dynamic organization of associations that serves as a kind of pre-adaptation to the probable appearance of a predator revealed the effectiveness against the tiger both randomly searching for prey and tracking it along a trail. The number of tiger attacks on the accompanying wild boars temporarily separated from the parental group was nearly three times (p < 0.05) as high as the number of attacks by the predator on maternal groups in key plots. In the relationships between the predator and prey species, (a) the location of the habitats of the maternal wild boar groups matters as well, in snowy winters also of compact sites, all usually at a distance from regular tiger routes; (b) disturbed wild boars broadened the search areas, under tiger pursuits and attacks they also changed the site; (c) the tuskers, the male wild boars that accompany maternal groups, often “covered” and “disguise” these groups by moving to the side of the most likely appearance by tigers.