I observed estrus in two adjacent troops (A-troop and M-troop) of wild Yakushima macaques during the 1984 mating season. A-troop females showed short and regularly cycling estrus periods, seldom came into estrus simultaneously, and scarcely failed to mate when they were in estrus. In contrast, females of M-troop, which went through troop takeovers during the mating season, demonstrated mate competition and subsequent estrus prolongation. Early in the mating season, constantly four to seven females of M-troop were in estrus simultaneously, competed for troop males (TMs), and some of them failed to mate. Subsequently many non-troop males (NTMs) approached to the troop, estrous females mated with them frequently, and mating harassments by females decreased. Among those NTMs, one dominated all TMs, which was referred to as a troop takeover. Successively three other NTMs dominated both all TMs and the former dominant NTM, and in total, four troop takeovers occurred in M-troop during this mating season. The females continued to be in estrus during the whole episodes. All the conceived females also showed prolonged postconception estrus, and they were neither inactive nor less attractive to males. It was suggested that M-troop females increased their opportunity to mate with NTMs by estrus prolongation, at the cost of female-female mate competition, to incite active male intertroop movement and subsequent troop takeovers.

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The purpose of this paper is to examine whether Jomon pottery from two neighboring sites can be chemically distinguished from each other. For this purpose, minor and trace element composition of Jomon potsherds from the Honmura cho and Isarago sites was determined using energy dispersive x-ray fluorescence (EDXRF). The results supported the hypothesis that the majority of the Early Jomon pottery from each of these two sites was produced locally using different raw materials. The paper also demonstrates the utility of multi-element, multivariate analyses for distinguishing pottery made in different locations.

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In order to investigate variability in the timing of human cyclic movement, we examined temporal parameters in stepping. Of 40 subjects, 22 were males (age: 23.0±2.6) and 18 were females (age: 23.2±1.7). They stepped at 10 or 5 kinds of tempos (steps/min) with either open or closed eyes. The CVs (coefficient of variation) of the temporal parameters were used to assess variability in timing. Sixteen of the 40 subjects also participated in a free stepping experiment. The results indicated that variability in the timing in the case of closed eyes was larger than in the case of open eyes, and variability in the timing of the non-dominant foot was larger than that of the dominant foot. We found that there are minimum CV tempos in the cases of both open and closed eyes (114.9±10.6 and 117.9±8.1 respectively), and there was no great difference between the minimum CV tempo and the tempo of free stepping in the case of open eyes.

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Eighteen cranial measurements including 6 flatness measurements of the facial skeleton were taken for crania from the Amami, Okinawa, and Sakishima Islands, which constitute the Ryukyu Islands. The data will be useful for future multivariate statistical analyses of Ryukyuan crania.

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