In this article, I review and discuss the present problems of Japanese primatology by looking back at the trends of the 1980s. The main themes are (1) the significance of the research on great apes, (2) the theories concerning the social structure of primates, (3) cooperation among the field sites of the great apes, and (4) recruitment of “good students”.

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Bonobos in the Wamba forest were intermittently studied by 22 researchers (16 Japanese among them) during a period of 18 years between 1984 and 1991. At least 6 unit groups consisting of two to three hundred bonobos inhabit this forest.
In 1976, artificial provisioning was adopted at Wamba. Now, three groups are provisioned, but not consistently. Observation of detailed activities or social interactions is facilitated by provisioning, though it affects patterns of ranging behavior, feeding ecology, and the grouping of bonobos.
Extensive interactions of researchers with villagers was another characteristic of the Wamba bonobo study site. Since bonobos live in the ecosphere (daily activity range) of villagers, the survival of the bonobos depends on the villagers' attitude toward them. We made every effort to impress upon the villagers that our presence (in other words, the presence of bonobos) at Wamba contributed to their welfare. We employed as many villagers as possible, distributed daily necessities such as soap, salt, clothes, and other items, as widely among the villagers as possible, and bought as many things as possible from them. Since the villagers have almost no cash income, and since it is difficult for them to obtain anything for daily use, as traders seldom visit Wamba, our activities influenced their daily livies economically.
The bonobos at Wamba used to be free from hunting or predation by humans, since a food taboo against bonobo meat had prevailed in this region. However, some people gave up this taboo, and poaching of bonobos began around 1984. It is possible that poaching was responsible for 10 out of 21 disappearances of bonobos from the El group between 1984 and March, 1994. Most disappearances occurred during the absence of researchers from Wamba, which suggests the presence of researchers contributes to the conservation of bonobos.
The Luo Scientific Reserve, including Wamba and the adjacent Ilongo forest was established in 1990. However, it does not serve to control poaching, since there are no official guards. Education of local people through investment on their school and medical care will be effective for gaining their support for protecting of bonobos.

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1. Among the bonobos in the Wamba forest, central Zaire, male mating frequency was not strongly linked with his dominance rank. However, his mating rate (number of copulations per hour) was positively correlated with his rank.
2. Three types of male dominance rank were taken into consideration, namely, rank within the group, party and patch. In bonobos at Wamba, males dramatically increased their temporary ranks (i. e., rank within a patch) by placing themselves opportunistically within the party space, and adult males in particular performed the majority of their copulations when they were the first ranking male within such a patch.
3. One case was observed in which there was a “sneaky” sexual solicitation by a male which corresponds to the “leaf clipping” display of Mahale chimpanzees.
4. It was concluded from 1, 2, and 3 that sexual competition among male bonobos at Wamba is more intense than has been thought, though other factors, especially the mother-son bond will influence males' mating success as well.

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Bonobos were observed daily at the feeding site in the Wamba forest in Zaire from Dec. 20, 1979 to April 16, 1980. The unit group, Elanga group, consisted of 2 subgroups, and adults of each subgroup are divided into a male class and a female class. The male class of one of the subgroups was further divided into 2 classes, a central male class and a peripheral male class. Thus the adult members of the unit group were divided into 5 classes, 3 classes of adult males and 2 classes of adult females. The condition of the parties which came to the feeding site was described with regard to the participation of adult male classes in the party; each male class either arrived independently of the other male classes, or in combination with two or more classes.
Female bonobos conducted the “dragging branch display”, which occurred during the same period as “females'attacks against adult males”. Both behaviors occurred in a narrowly limited period within the whole study period. However, females did not direct their “dragging branch behavior” to adult males. Females avoid one to one confrontation with adult males. Females' “dragging branch behavior” has the characteristic of a display which facilitates the avoidance of one-to-one confrontations.
Males conducted both one-to-one directed and undirected “dragging branch behavior”. Subordinate males tended to direct their “dragging branch behavior” toward dominant males. The behavior has the characteristics of a “challenge behavior from subordinate against dominant males”, not the avoidance of direct confrontation. Most of the “dragging branch behavior” between males and females was directed from males to females. There was a strong tendency that bonobo males did not attack females of the same subgroup. These facts indicate that bonobo males were subordinate to females, and that males were challenging females.
“Directed running without dragging branch” was usually conducted by the dominant against the subordinate among males, indicating that the behavior is a dominant behavior. However, this behavior was conducted in both directions between males and females, showing unclear dominance.
Dominance among males seemed to be dually determined, one by interactions among males, and another by the influence of supports by females. Supports by females (involving mothers) were unstable depending on the changes of females'physiological conditions.
Though males did not attack females of the same subgroup, males attacked females of the other subgroup. Thus, when 2 subgroups came together, females' influence on males from different subgroups decreased. The encounter of different subgroups served to destroy the society based on mother-son bonds. This fact implies a different view from that in which females are seen to initiate fusion of groups at group encounters.
Since each of the behavior patterns, “females' attack against males” and “females'dragging branch display” occurred within a limited period, the cause which brought about these behaviors was sought in the interactions in the preceding period. An attempt was made to find a chain of causes and effects between preceding and subsequent periods. This method introduces stories among the consecutively occurring social events. This method produces “stories” from consecutively occurring social events. This method may substantiate to some extent the anthropomorphic expressions which usually have been used in literature written in Japanese dealing with social dynamics of primates.

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Peering behavior in wild bonobos (Pan paniscus) was studied at Wamba, Zaire. A total of 230 peering episodes were recorded on an adlibitum basis in two artificial feeding sites. Peering behavior was often directed from younger individuals toward elder ones. In particular, adult females were most frequently involved in peering, with individuals of all age-sex classes. On the other hand, adult male bonobos seldom took part in peering behavior. There were four types of behavior which followed peering: (1) the peerer left the place, (2) the peerer left the place, (3) both stayed at the place, (4) some other social interaction followed. Type (4) was the most frequent. Peering behavior usually led to tolerance by older or dominant animals of a younger or subordinate animal's subsequent actions directed towards the former. Peering behavior was thus concluded to be a unilateral action for initiating affinitive interactions by the peerer.

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Immature bonobos genital contact behavior with individuals of most age classes. Genital contact between immature individuals was most frequently performed in the ventro-ventral posture. It was usually observed during play sessions, and males participated more frequently than females. Both males and females perform genital contact with adult males though not so frequently. On the other hand, only males frequently perform genital contact with adult females and its frequency increased with age. As they grew older, genital contact behavior of immature males with adult females became more like copulation between adults. By contrast, immature females did not have any genital contact behavior that resembled copulation. Females became very active in copulation with adult males and genital contact behavior with adult females after they had moved to non-natal groups.

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The social play behavior of the bonobo (Pan paniscus) was studied in a provisioned group at Wamba, Zaire. Case studies revealed characteristics of the play of this species. (1) An older female participated in a play of make-believe with a young adult male. (2) There were cases in which an adult or adolescent male did play with an infant or a juvenile. A possibility of the existence of a mechanism that conveys information from a generation to another were discussed. (3) Play behavior among adult and adolescent males were observed, and in some case the play functioned resolve tensions among them. (4) Various types of sexual play were observed, from typical play to play-like solicitations. The concept of “field of interaction”, that is determined by “relation structure”, was presented and “play field” was discussed. The position of play in a coordinate with axes of degrees of freedom in relationship among individuals and in behavioral patterns were discussed. The intimate relation between play and human language in the coordinate were emphasized. It was asserted that play is one of the most interesting phenomena for primatologists to study.

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After being defeated by other males, three alpha male chimpanzees in the Mahale Mountains National Park, Tanzania, became peripheral, spending much of their time alone. A very similar life style was observed when a male was left alone after all the other chimpanzees of his unit-group emigrated or disappeared. Observational evidence suggested that these males remained within the ranges of their original groups, only sometimes forming associations mostly with the familiar females and their offspring and rearely with the familiar males, but never with any strange chimpanzees. It seems that female chimpanzees tend to choose a larger group into which they immigrate. It also seems impossible for adult male chimpanzees to join another social network already established among other unrelated adult males. These factors force such males to remain within their familiar ranges as lone chimpanzees.

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Social interactions of the second ranking male chimpanzee, Nsaba, were analyzed at M group of the Mahale Mountains National Park, Tanzania, comparing with those of a middle ranking male, Aji, who was as old as Nsaba. Both Nsaba and Aji spent more time in proximity to and grooming with adult males than individuals of any other age/sex classes. As a whole, they engaged in grooming reciprocally with adult males, groomed adult females more than were groomed by, and groomed adolescent males less than were groomed by. However, Nsaba almost onesidedly groomed some adult males, while Aji engaged in grooming reciprocally with most adult males. They were frequently pant-grunted at by adolescent males and adult females. They uttered about 2 pant-hoots an hour, some of which were followed by aggressive displays.
Nsaba had a strained relationship with the alpha male Ntologi. Although he sometimes pant-grunted at and followed Ntologi, they did not groom one another. Furthermore, Ntologi performed aggressive displays at Nsaba, especially when he stayed together with Kalunde, the third ranking male. Nsaba sometimes traveled alone, avoiding Ntologi's aggression. Ntologi seemed to have tried to form coalition with Kalunde and opposing him against Nsaba. However, Kalunde frequently engaged in grooming with Nsaba when Ntologi did not stay nearby. Coalition strategies among males were discussed, focusing on the second ranking male.

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Use of leaves for drinking water by wild chimpanzees was studied through a field experiment. Previous observations have revealed that the chimpanzees at Bossou, Guinea, drank water by using a leaf as a spoon or a sponge. In addition to recording the leaves used in a tree hollow under natural conditions, we set up an outdoor laboratory for observing and video-recording the behavioral processes of the tool-use behavior. A water container which was utilized by local people was buried in the ground of the outdoor laboratory. We observed 5 examples by 3 chimpanzees in which leaves were used as a drinking tool. The observation revealed a third method of using leaves: The chimpanzees folded a leaf in the mouth as in paper-folding and put it into the container for capturing water. The chimpanzees preferred to use a particular leaf (Hybophrynium braunianum), a wide, soft, and hairless leaf, as a tool (21 out of 28 episodes in total). The high selectivity of leaves and the newly-found folding method shows chimpanzees' ability to find a suitable material and modifying it into a useful tool.

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The hand preference of chimpanzees based on observation of their tool behavior was studied in the Mahale Mountains National Park, Tanzania. Observations and recording of ant fishing were conducted to study their tool behavior. The research was conducted during a period of 7 months from August 1992 to February 1993. Handedness in the use of fishing probes was examined for 49 individuals. Chimpanzees are basically two-handed in the use of probes, though a minority has a one-hand preference. For this reason, the relationship between the location of the nest-entrance and the position in which a chimpanzee can preserve its balance in the tree strictly determines which of the hands can be used. Chimpanzees are two-handed, and can fish for ants with either hand. The skill of ant-fishing does not always favour the evolution of one-hand preference. Thus, chimpanzees are variable in the use of hands, from almost one-handed to almost two-handed individuals. The use of fishing probes for ants does not necessitate the exclusive specialization of one-handedness in the manual dexterrity.

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On 4 Oct. 1988, a chimpanzee infant, the named Jacky, got entangled in rope at the outdoor enclosure in Tokyo Tama zoological park. His mother, Jarny, disentangled her son's neck from the rope and carried him inside according to the keeper's order. The keeper entered the room with Jarny and tried to get her to hand the infant to him to rescue him. But she kept hold of Jacky. The keeper ordered her to put the infant on the floor. Jarny did so and left the room. Though the vets and keepers tried to revive him through artificial respiration, he died.
This short report described on the chimpanzee behaviors on the next day after Jacky died. The mother ran to the rope that had twined round her son's neck the day before and cried ‘Wow, Wow, Wow’ just after leaving her room. The other group members came near Jarny by turns to look at her face and/or groom her. They stayed with her for much longer time than usual. Other mother chimpanzees always stayed near and/or looked at and/or huggud their infants. After 3 years, Jarny was observed to rush to her next infant who put the rope on his neck with screaming.
Did the chimpanzees understand the death of Jacky? They are seemed to have the ability of ‘empathy’ like as humans.

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It is well known that feral chimpanzees use objects as tools. A long time is required for a young chimpanzee to learn the tool-use skill specific to his or her community. This study focuses on orienting manipulation as a precursor of tool use. Orienting manipulation is defined as an action in which an object is manipulated with respect to another object. I extracted 3 types of orienting manipulation, distinguished by the destinations toward which an object was oriented, i. e., 1) orientation to the substrate; 2) orientation to her/his own body; and 3) orientation to another detached object. Three young chimpanzees, aged 2 to 4 years, served as subjects. All was conceived by artificial insemination. Two of them were artificially reared and one was reared by the mother for the first year. They received a set of four diagnostic tests for orienting manipulation: stacking wooden blocks, placing a disk into the circular hole in a board, inserting a stick into the holes of a box, and making a nesting structure from three seriate cups. The test materials and procedures were exactly the same as those adopted for diagnostic tests of cognitive development in human children. The performance of the three young chimpanzees reflected their age rather than the rearing conditions. The performance of 2 year old chimpanzee was close to that of 1 year old human children. The performance of the 4 year old was close to that of 1.5 year old human children. In general, the developmental processes of orienting manipulation were similar in both species.

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Since Schaller conducted a extensive survey on the distribution of eastern (mountain and eastern lowland) gorillas in 1959-60, several surveys have been made to estimate their densities and ecological characteristics within their range. Mountain gorillas inhabiting the Virunga and the Bwindi forests have been well protected and the recent censuses show a slight increase in their populations. On the other hand, eastern lowland gorillas have been found in small isolated populations scattered in eastern Zaire. Some of their lowland habitats, such as Kasese, which gorillas are expected to survive in high density, are still outside the national parks. Gorillas in these habitats are regarded as pests of crops by local people and are menaced in danger of extinction.
Distribution of eastern lowland gorillas are discontinuous even inside the national parks (Maiko and Kahuzi-Biega) and a new Reserve (Itombwe). A census conducted in 1990 suggests that gorillas have been concentrated in the wellprotected areas. Such change in their habitat-use has increased their density in small areas, may have stimulated female transfer between groups, and resulted in the prominent reduction in the size of groups. Increasing human disturbances have prevented gorillas from traveling between lowland and highland habitats.
A civil war, which occured in Rwanda, broke all the conservation efforts made by the recent international cooperations. It produced three milion of refugee people, who rushed to neighboring countries. Since people who had been engaged in research and conservation of mountain gorillas in Rwanda evacuated to the other countries, gorillas are now in unsafe situations. Deforestation is increased by refugee people in Zaire. More international aids are urgently needed to save refugee people and to preserve natural environments in both Rwanda and Zaire.
The future project of gorilla conservation must consider the inprovement of infrastructure with sustanable development of local people. To promote eco-tourism is one of the best way to adapt local development to the purpose of open-field museum. Reseach institutes will take a important role to enlarge the functions of national parks and to increase income from foreign countries, such as public information services, education or monitoring survey. Foreign institutions and researchers should cooperate with national parks and researchers in habitat countries to discuss the future plan for conservation.

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The orangutan population and habitat variability analysis (PHVA) workshop stated that the population and the distribution of orangutans decreased very much over the past 20 years. The author has studied the ecology of orangutans in Kutai national park, East Kalimantan, Indonesia since 1983. The situation of orangutans has changed since the great forest fires and droughts and the coal mine operation. The distribution of orangutans in East Kalimantan is reported and status and the future plans for conservation of orangutans are discussed in this paper.

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The author studied the social relationships among each individual orangutans since 1983 in the Kutai national park, east Kalimantan, Indonesia. He presented the hypothesis that orangutans have a rather open and loose society consisting of big sized social units of 20-30 individuals, as in chimpanzees (Suzuki 1985a, b, 1992). The observational data on individual orangutans shows that this hypothesis should be adapted for to the populations of the upper and down stream areas of the research area up to 1988, but since 1990 the relations of individuals has changed at the research site. Futher research is necessary to clarify this issue.

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