In order to clarify the change of maternal immune function during pregnancy, we examined the change of the percentages of T cells (including CD4 and CD8 subsets), B cells and natural killer (NK) cells in pregnant cynomolgus monkeys. The percentage of CD4 cells decreased significantly in the first trimester, whereas that of CD8 cells increased in the first and second trimesters compared with non-pregnant monkeys. There was a pronounced decrease in the percentages of B cells in the second trimester. The percentages of CD16⁺ NK cells declined slightly in the first trimester. NK activity determined by flow cytometry also decreased in the first trimester similar to the change of CD16⁺ cells. The percentage of CD16⁺CD56⁺ cells which is the NK subset with high NK activity significantly decreased in the first trimester. Although NK activity were significantly correlated with the percentages of CD16⁺CD56⁺ NK subset in the non-pregnant monkeys, NK activity was not correlated with CD16⁺CD56⁺ subset level during pregnancy. From these results, it was proved that the percentages of T and B lymphocyte subsets and the function of the NK cells might change during pregnancy in cynomolgus monkeys. These alterations in specific and non-specific immune systems occurred in the first and second trimesters and restored to the level of non-pregnant monkeys in the third trimester.

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Whether Japanese macaques can discriminate male from female conspecifics was investigated using color photographs of faces. Each trial began with the presentation of two photographs, one male and one female, on the monitor. Five different pairs of male-female photographs were used. Pairs were never mixed-i. e., a particular male photograph and a particular female photograph defined the stimulus pair. If the subjects touched the male photograph first and the female photograph second, they received a food reward. Selected photographs disappeared. In Experiment 1, the subjects learned to select five different male-female pairs in the male-first-female-second order, indicating that the subjects can discriminate the photographs of their conspecifics. In Experiment 2, the photographs displayed in Experiment 1 were again displayed, but the male-female photograph pairs were not fixed as in Experiment 1. Any of a total of 25 different male-female pairs could be displayed. The subjects selected the male photographs first and the female photographs second in any male-female pair. In Experiment 3, six novel photographs of conspecifics' faces (three males and three females) were added to 10 familiar photographs. The procedure was otherwise the same as in Experiment 2. It was found that when novel photographs were presented with the familiar female photographs, performance was not disrupted, however, when familiar female photographs were replaced with the novel male or female photographs, performance was disrupted.

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A measure of cranial size is calculated for 15 samples of 11 macaque species by means of a principal component analysis of variancecovariance matrix of logarithmically transformed 17 cranial measurements. The sex difference of cranial size (CSSD) is defined as a ratio of male cranial size to female cranial size. CSSD shows a weak tendency of negative correlation with several body size measures, and a low level of positive correlation with body weight dimorphism. Associations of CSSD with mating patterns (Caldecott, 1986), relative testis weight (Harcourt, 1981), canine dimorphisms (Plavcan et al., 1995), maximum values of intrinsic rate of natural increase (Ross, 1992), weed or non-weed dichotomy (Richard et al., 1989), and female dominance style (Matsumura, in press) are all weak or insignificant. While CSSD ranges widely among the “paraphyletic” silenussylvanus species group (1.107-1.172), the CSSDs of the two “monophyletie” species groups minimally overlaps; 1.093-1.142 in the fascicularis species group and 1.142-1.160 in the sinica species group including M. arctoides. Sympatry among macaque species appears to strongly influence CSSD; 1.172-1.160 in tropical isolated species, 1.153-1.125 in sympatric heartland species, and 1.121-1.093 in subtropical or temperate isolated species.

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The number of Japanese macaques (Macaca fuscata) has rapidly increased under artificially provisioned conditions. At Takasakiyama it increased by 6.9 times during 22 years from 1953 to 1975 when food was given at 618kcal/day/head on average. To control the population growth, provisioning was decreased to 334kcal/day/head from 1975, after which, it increased only by 1.2 times for 19 years until 1994. Destruction of the forest from the increased number of monkeys has continued, however, through eating fruits, shoots and young leaves of the main food trees. Yearly consumption effeciency of monkeys in the forest for 1990 was calculated as 8.7%, which is near to the African elephant. As a result, the vegetation type is changing from that of natural forest. Computer simulation revealed if the population decreases to 60% of its current size and 282kcal/day/head of artificial food is given, consumption efficiency will decrease to 5.8% and the population can be kept almost stable. Further manipulation of the monkey population is necessary at present by altering mortality, natality or both. Supply of many free-ranging monkeys to biomedical experiments should not be recommended from the stance of animal welfare and the quality of experimental animals. On the other hand, temporary birth-control of each cycling female is to be considered. The principle of population control is to keep population parameters at about the level of the natural condition.

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The mixed lymphocyte culture (MLC) responses were examined among family members including offspring who were born from the mating between father and daughter. The lymphocytes from three inbred offspring did not induce MLC responses in lymphocytes from both father and mother monkeys but parent's lymphocytes could stimulate the lymphocytes from offspring. These three offspring included two half-blood sibling whose lymphocytes did not stimulate each other. This result suggests that these three inbred monkeys might be MHC homozygote but two monkeys might share the same MHC.

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Tool-using behaviors of animals have been compared with those of early-man and examined the factors which differentiated the human culture from that of animals. Many tool-using behaviors of animals which are mainly found among birds and primates, particularly in chimpanzees, are flexible to environmental change and have local differences. The reason why they are remarkable only among some separated animal taxa are to be examined through their environment, life form, feeding repertoire and technique. Chimpanzees use and make many different kinds of tools, occasionally do more than one kind of tool for a single purpose and are expected to use a tool for making another tool which needs high intelligence and capability. Examination of local differences of tool-using repertoire of chimpanzees and their environment made clear that they maintain techniques through social tradition, which can be called “culture”. However, its elaboration to man-like culture needs further development of the motor function coordinating both hands and communication method by language.

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Recent studies on the mechanism of social transmission in animals (Galef 1988, Whiten & Ham 1992) revealed various types of observational learning, particularly local/stimulus enhancement. This type which includes both “the acquirement of partial information from other individuals” and “trial and error” suggests that the primitive forms of social learning can be regarded as simple extensions of individual learning. From this viewpoint, I investigated two instances of social transmission in free-ranging Japanese macaques: tool-using (stone-throwing) and louse-egg-handling techniques during grooming. In the latter, the distribution of these techniques suggests social transmission based on maternal kin and the social system of dominance -the tendency of subordinates to groom more often than to be groomed- may result in oblique transmission of various techniques from low-ranking monkeys to some offspring of high-ranking females.

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One of the important characteristics of human tool-use is that tools are used for social purposes in conjunction with technological uses. The analysis of social use of hunting tools among contemporary African hunter-gatherer societies shows: 1) the owner of a tool is the one who makes it; 2) the owner of the animal is the owner of the tool used for killing it; 3) tools are frequently exchanged, or borrowed and lent, which involves social manipulation of ownership and sharing of the hunted meat; 4) The meat owner shares the meat, obligatorily to the participants according to the role they play in the hunt, and voluntarily to other band members and visitors.
Thus in hunter-gatherer societies, tools serve as excellent means for social manipulation. This may shed some light on the question of evolution of human intellectual capacity, and integrate seemingly contrastive ecological and social hypotheses concerning the factors for intellectual evolution; the former emphasizing the importance of tool-use for manipulating the environment, and the latter of social manipulation of inter-individual relationships.
The lending of hunting tools can be regarded as indirect, delayed participation of the owner in cooperative hunting. The obligatory meat sharing is, therefore, performed according to the system in which sharing is prescribed by the preceding cooperation in hunting. Human hunter-gatherers are unique in that they integrate cooperative hunting and meat sharing into a single system of “hunting -sharing complex”. While non-human primates, chimpanzees in particular, show both cooperative hunting and meat sharing, these appear to be separate events, and are not integrated into a single system.

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The paper focuses on the distinction between early hominids and modern non-human captive primates with particular reference to the lithic tool production, i. e. fundamental fracture patterning on the core and flake surfaces.
The earliest lithic tool from West Gona site, Afar, Ethiopia shows that the flaking scars or negative flake surfaces are extended to the central part of the core. Together with another early Oldowan industries, the lithic tool characterlistic of early hominids can be summarized as a harmonious combination of large, medium, and small flake negatives on a given tool. On the contrary, lithic tools made by a captive Bonobo chimpanzee represent mostly flaked marginally around a core periphery; and detached flakes are also small.
It is, therefore, possible to hypothesize that the critical argument of distinctive criterion between “Man the tool-maler” and “Pan the tool-maker” lies in the production of lithic flake and it's use, on the basis of phylogenetic relations. Additionally, intermediate character of long-bone fracture using hammer stone by captive chimpanzees, in the setting of nut-cracking and the stone flaking, is also discussed.

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Changes of the human interface is discussed according to the changes of means for work; from tools to machines, from machines to electrical machines (computers). When we use a tool, the operation is mainly hand/arm movements with high degree of freedom. The feedback of the operation from the tool is mainly somatosensory. The operation of a machine is done by simple operation, and feedback from the machine is obtained through visual channel. The operational movement to a computer which has a keyboard and a visual display terminal has less degree of freedom than that to a machine, and the feedback strongly depends upon the visual channel. However, graphic user interfaces (GUIs) let the operator to use two dimensional movements of the operation because the operator moves his hand to use a mouse type interface device. Recently, technologies for the virtual reality and those for the multi-modal interface allow to introduce the three dimensional hand movement to the computer operation and tactile/force display to obtain feedback from the computer. When the means of work changed from tool to machine, the operation became simple and visual feedback became important. However, the new technologies can make the human-interface of the computer to be closer to that of the tool. There are also technology trends to introduce verbal communication to the human-interface.

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Now that we already know that Chimpanzee can make, use and improve tools, even though yet simple and not many, and inherits techniques as culture by learning, what we should do now is to discern, with more elaborated distinctive criteira than ever before, what aspects should be continuous and discontinuous between chimpanzee and Homo sapiens.
For innovation and learning in the tools use, imitation, self-recognition and inference under presupposition of if-condition are important competences. We know that chimpanzee has all of them. In spite of such chimpanzee's competences, the variety of instrument chimpanzee has invented is very limited comparing to Homo sapiens.
Language is a unique tool which make easily possible 1) to represent images of mental experience according to the liguistic codes as social fact, 2) to self-refer modalities of speaker (belief, probability, conditionality etc.) to the talked, 3) to recall propositional believes apparently not relevant to the situation here-and-now and mutually refer between them, 4) to check whether correspond or not with each other the mental images individually supposed by interlocutors. Language, as interface between brain and outer world and between individuals, is very effective tool for communication and inference. Chimpanzee has competence to laugh in playful situation as self-reference of unexpected experience. But it is mostly sure that he does not laugh as a third person. The fact that only Homo sapiens who speaks can laugh as a third person suggests that we, being equipped with language, began to live in a new intersubjective world where learnings and innovations are carried out.

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