Anesthesia was used to reduce filial cues to maternal behavior in Macaca fascicularis, and changes thereby in the mothers' behaviors toward their own and alien infants were observed. Effects of infants' general anesthesia on the mothers were obvious in increses in their grooming and sniffing toward younger infants aged 60 days or less, and in decreases in their contact and embrace toward older infants aged 61 days or more. Anesthetized younger infants of the mothers' own were directed contact and grooming more frequently by the mothers than were alien anesthetized younger infants. Aggression was not observed toward the anesthetized infants. Thus, loss of movement in the infants revealed an active role of the mothers of the younger infants to maintain relationships with their offspring, but this active role decreased in the mothers of the older infants. In the second part of the study, an odor of generally anesthetized infants was reduced by hypoesthesia of mothers' olfaction. As a result of this, sniffing decreased toward the younger alien infants and so did grooming toward the younger own infants. The effect of olfactory hypoesthesia in the mothers was thus seen only toward the younger infants, which indicates an active role of young infants' odor in arousing the mothers' positive attention to them.

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In vitro responses of lymphocytes to PHA, ConA and PWM as well as the mixed lymphocyte reactivity (MLR) were determined with 83 pregnant cynomolgus monkeys (Macaca fascicularis) from 39 to 157 days of gestation age. The mitogenesis to PHA in pregnant monkeys was significantly lower during 5 to 8 weeks and more than 20 weeks after conception than in non-pregnant animals. The responses to ConA and PWM did not change during the first 18 weeks of gestation, but decreased remarkably after 20th week.
The mixed lymphocyte reactivity was also significantly decreased after 20 weeks of gestation age. This highly significant reduction was observed regardless of the origin of stimulator cells; mated male lymphocytes or third party male lymphocytes. This finding suggests that the depression of MLR in the present study is not specific to fetal histocompatibility antigens but nonspecific. In addition, MLR was apparently suppressed when maternal lymphocytes were incubated with autologous serum (pregnant serum) as compared with that when incubated with pooled young male serum. From these results, it can be postulated that the mixed lymphocyte reactivity of maternal lymphocytes is suppressed by some soluble factors that may be contained in pregnant serum 20 or more weeks after conception.

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Among 62 adult females of Arashiyama B troop, a linear dominance rank order was found. The dominant-subordinate relations among kin-related females tended to follow Kawamura's (1958) two principles, although the converses were not rare. A linear rank order also existed between kin-groups. There was no consistent correlation between female rank order and reproductive success in Arashiyama B troop. The female rank order may have originated in the adult daughter's inhibition against superseding her mother; i. e., the primary function of female rank order may not be competition for reproductive success, but may rather to permit coexistence within a troop.

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A troop of Japanese monkeys at Takaskiyama has been artificially fed since 1953 and the population which divided into 3 and more troops grew from 250 to more than 1900 (Table 2). Artificially given food increased but, after 1975, decreased. Population parameters, especially growth rate, remaining rate to Takasakiyama, socionomic sex-ratio, adult female rate to the population size, birth rate to the adult female (natality) and primiparous age are compared with the food volume (Table 1) and with each other (Table 6). Nutrition given at the artificial feeding ground clearly influenced on the population parameters, especially on the growth rate, birth rate and primiparous age. Growth rate and socionomic sex ratio were influenced by the capture as agricultural pest, but remaining rate to Takasakiyama was not much influenced by the change of the nutrition. Changes of parameters were compared with those of the Ryozenyama population which was baited in a certain period and, then, left in the forest. The present nutrition intake by an animal at the artificial feeding ground as well as in the forest at Takasakiyama is a little more than that taken by wild animals. This study suggests that the artificial feeding should be controlled to the similar nutritional condition as that for wild animals.

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Audition, speech perception and phonation of the chimpanzee were studied to understand the course of evolution of human speech. (1) The chimpanzee showed W-shaped auditory sensitivity which is similar to that of monkeys and different from that of humans. The origin of the 4kHz dip was discussed. (2) The discrimination of vowels and consonants was studied using a reaction time task. The chimpanzee required long latenties in discriminating [i] from [u] and [e] from [o]. The relationship between the auditory sensitivity and the perception of vowels was discussed. The chimpanzee was reported to make use of the pitch and the 3rd and the 4th formants to normalize vowels. The chimpanzee showed categorical perception of the voicing and the place-of-articulation features of stop consonants. (3) The chimpanzee did not utter [i] and [e]. The small pharynx was suggested to be responsible for this repertoir of vowl-like sounds. The relationship between perception and production of vowels was discussed and it was suggested that the evolution of audition was matched to that of phonation. The difference in the vocal development between chimpanzees and humans was also discussed. (4) Auditory cortical neuronal responses of the Japanese monkey to conspecific coo sounds were reported. The neural lateralization of vocal reception in primates was discussed.

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A survey was conducted from July to December 1987 on primates inhabiting the Mt. Kahuzi, Masisi, Irangi and Itebero-Utu regions of Kivu District, Zaïre. Ten diurnal primate species were confirmed to survive in these regions based on direct observations, field signs and personal communications by Park Wardens or local people. The estimated densities of gorillas and chimpanzees were 0.83head/km² and 0.91-1.1head/km² respectively, in the Masisi region; and 0.27-0.32head/km² and 0.27-0.33head/km² respectively, in the Itebero-Utu region. Gorillas frequently used secondary regenerating forest, while chimpanzees used primary forest in both regions. Other primates have possibly become reduced and changed in their distributions in comparison with those reported previously. Colobus angolensis was not, and Cercopithecus l hoesti was rarely found in the 4 regions. Papio anubis invaded the bamboo zone of Mt. Kahuzi, and C. l hoesti and hamlyni had descended into the lowland forest. Deforestation, hunting pressures and other human distrurbances have recently increased in the Masisi, Irangi and Itebero-Utu regions. It was said that 9 primate species were raiding at least 12 high valued crops. Most of the primate species faced serious problems and were in danger of extinction in these 3 regions. Especially in Masisi, where the mountain slopes had been entirely cultivated, the primates ranged within several small forestry patches around the top of the mountains or in the valleys. Gorillas frequently appeared in farms or pastures, and a struggle between them and the local people had gradually increased. An immediate decision must be taken to separate the gorillas and their habitats completely from the human activities in Masisi. A conservation policy should be implemented urgently, incorporating local management plans. Present and future conservation projects are discussed, and several detailed recommendations are made in this paper.

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