Abstract and Summary
1. To demonstrate the existence of territoriality in a male sika deer (Cervus nippon) population during the rut, I made a behavioral and sociological study for 11 months from 1977 to 1979 in Nara Park, Japan. 82 ♂ ♂ were identified and divided into territorial ♂ ♂ (TMs) and nonterritorial ♂ ♂ (NTMs) on the basis of behavioral characteristics and the spatial distribution of their home ranges.
2. All TMs were five years or older. Based on the occurrence or absence of certain behavior patterns, it was possible to recognize core areas, territories, and peripheral areas as substructures within the home ranges of the TMs. The home ranges of TMs did not overlap very much. The locations of some of these home ranges were approximately the same year after year although size and shape changed slightly. Changes in the ownership of such home ranges resulted from dominance reversals. By contrast, there were large overlaps of home ranges of NTMs, and their home ranges were significantly larger than those of the TMs.
3. 16 distinct behavior patterns in ♂-♂ interactions were classified into three basic categories; dominance, contact, and submissive. The majority of the dominance patterns occurred in the interactions of TMs, and the TMs rarely performed submissive patterns. They treated all NTMs alike regardless of difference of social classes within the latter. Apparently, the ♂ ♂ were able to recognize ♂ ♂ of other social classes by appearance. Behavior and rank of each ♂ was directly related to the configuration of his antlers. ♂ ♂ interacted most intensively with ♂ ♂ of their own class. Behavior during interactions was typical of each class. A shift in the social position led to considerable changes in behavior.
4. 13 separate sexual behavior patterns were recorded. These were used by ♂ ♂ in five phases of the mating ritual; preliminary, enclosing, touching, mounting, and copulation. TMs accounted for 57.4 % of the sexual interactions observed and for 76.2 % of the copulations. Thus the TMs were significantly more successful in breeding ♂♂ than the NTMs. TMs interfered in 81.3 % of the mountings of NTMs. Moreover, the frequency of mounting in NTMs was checked by dominance relationships between the ♂ ♂; subordinate ♂ ♂ were socially castrated.
5. Marking behavior was sometimes performed as a reaction to marks of other ♂ ♂, sometimes it occurred when no specific external stimulus was evident, and it sometimes was observed during agonistic interactions. TMs accounted for 65.8 % of all the marking recorded. Marking behavior apparently served as a kind of self-advertisement and to saturate the home range with the ♂'s own scent.
6. 6 types of male vocalizations which seemed to play a role during the rut were sound spectrographically analyzed. The howl apparently advertised occupation of an area to potential competitors. Moans were associated with a wide variety of activities. They also advertised the presence and the position of the caller. TMs accounted for 92.5% of the moans. The majority of the calls were made either in response to another's moan, or as an expression of agonistic intentions toward another individual. Only ♂ ♂ whose peak call rate was more than 6 per h succeeded in establishing territories.