The present fossil evidence indicates that hominoids originated in Africa with the oldest fossil hominoid being probably Kamoyapithecus hamiltoni from the Late Oligocene (25Ma) of Lothidok, northern Kenya. Plenty of hominoid fossils like Proconsul have been found from the early half of the Miocene in East Africa for decades. In the late Early Miocene, some relatively primitive type of hominoids left Africa, and entered into Europe through Anatolia with the oldest hominoid record in Europe being 16.5Ma. In contrast, hominoid fossils of similar ages have not been reported from Eastern Eurasia. It is during the late Middle Miocene (12-13Ma) that hominoids with partly modern aspects appeared both in Western (Dryopithecus) and Eastern (Sivapithecus) Eurasia.
In Eastern Eurasia, Neogene hominoid fossils have been discovered mainly in Indo-Pakistan Siwaliks and in the Yunnan Province of southwestern China. Few exceptions were Tinau Khola (South Central Nepal) and Wudu (Gansu Province, China). Recently, a cooperative paleontological research between Thailand and Japan discovered a new Miocene hominoid locality in northern Thailand.
Most hominoid fossils collected from Indo-Pakistan Siwaliks are attributed to Sivapithecus with a very few exceptions (“Gigantopithecus and Dryopithecus” or “Hylopithecus” simonsi). The taxonomy of Sivapithecus at the species level is problematic, though three species (S. indicus, S. sivalensis (or punjabicus), and S. parvada) are generally recognised mainly based on their size. Sivapithecus is ranging temporally between the late Middle Miocene (12-13Ma) and the mid-Late Miocene (7-8Ma). Although Sivapithecus is verly likely to be ancestral to living orangutans, their evolutionary history is little known after the disappearance of Sivapithecus from Siwaliks, following the drastic changes in the local paleoenvironments related to the global paleoclimatic changes around 7-8Ma.
In East Asia, the best known Neogene hominoid is Lufengpithecus lufengensis from Lufeng (ca. 8Ma) in the Yunnan Province. There are hundreds of craniodental specimens including a few male and female skulls, but the postcranial material is very rare. Lufengpithecus lufengensis was once thought to be two different taxa: Sivapithecus yunnanensis for larger specimens and Ramapithecus lufengensis for smaller specimens. However, as Ramapithecus in Siwaliks was synnoymized to Sivapithecus, the Lufeng material also came to be considered to represent a single species with a very high degree of sexual dimorphism. Because the Lufeng material lacks some of the possible shared derived cranial characters between Sivapithecus and orangutans, a new genus Lufengpithecus was created by Wu (1987).
In addition to the above mentioned fossil hominoids, the subjects of this article include other less known fossil hominoids and the paleoenvironments of the Neogene Eastern Eurasia.

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The joint Japan-Thailand expedition surveyed the Miocene basins in Northern Thailand from 1996 to 2002. The Miocene sediments in the Northern Thailand yield many vertebrate fossils. Mammalian faunas from the Northern Thailand resemble those from the Middle Miocene of the Siwaliks in Pakistan according to previous works. We examined the vertebrate fauna of the three Miocene sites, Mae Soi, Chiang Muan, and Sop Mae Tham of the Northern Thailand.
At Mae Soi 50km south west of Chiang Mai, a primitive amebelodontid gomphothere, Archaeobelodon, and equids was collected, At Chiang Muan Lignite Mine 150km east of Chiang Mai (the Chiang Muan Formation), we found fossils of a large ape, suines, and a primitive tetralophodont gomphothere. The mammalian fauna from the Chiang Muan Formation suggests the latest Middle Miocene age. At Sop Mae Tham, we found a new Late Miocene fauna. It includes the Hipparionini (Equidae), which has never been recorded in the Neogene of Southeast Asia. The Sop Mae Tham mammal fauna consists of tetralophodont gomphotheres, rhinocerotid, hipparionin equids, Listriodon and suine, tragulids, Boselaphini and primitive bovids. This mammalian assemblage suggests the early Late Miocene age.

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Physiognomic analysis using CLAMP technique of Wolfe (1933) was performed to two plant megafossil assemblages from northern Thailand intramontane basins to obtain quantitative data on the mean annual temperature (MAT), cold month and warm month mean temperatures (CMMT & WMMT) and growing season precipitation (GSP). The assemblage from Ban Pa Kha (BPK), a subbasin of Li Basin, dated as Late Oligocene, consists of 30 types of woody dicotyledonous leaves along with infructescence and inflorescence of alders and winged-seed of maple, as well as conifers. Physiognomic analysis of the fossil angiosperm leaves implies a MAT of 17.60°C, CMMT and WMMT of 7.5 and 27.80°C, and GSP of 324.5cm. Its composition and physiognomic feature correspond well with Notophyllous Broad-leaved Evergreen Forest of Wolfe (1979). Assemblage from Mae Lai basin (ML) of late Early to middle Middle Miocene age consists of 36 types of dicotyledonous leaves with no component of “Laurasian montane element” proposed by Morley (1999). Climate variables obtained are a MAT of 19.20°C, CMMT and WMMT of 12.5 and 26.30°C, and GSP of 214.7cm. Although MAT estimate is slightly lower than expected, floristic composition of ML can be comparable to Paratropical Rain Forest of Wolfe (1979). MAT estimates indicate the warming trend from the BPK to the ML time. CMMT estimate from BPK is 5 degree lower than that of ML, whereas WMMT is even higher in BPK. This suggests that decrease of mean annual range of temperature, caused mainly by an increase of CMMT, result in the reduction of temperate elements and expansion of paratropical evergreen forests by at least Middle Miocene. GSP estimates indicate perhumid Late Oligocene climate and humid but much smaller precipitation in the Mae Lai time. This change might be ascribed to uplifting Tibetan plateau and the onset of monsoonal climate before the Mae Lai time.

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Northern Thailand has numerous basins filled with the Tertiary non-marine Mae Moh Group more than 2000m thick. They are composed of sand, silt, clay, and lignite beds indicating lacustrine and fluvial environments, and yield plenty of Miocene mammalian fossils including hominoid and Proboscideans. These sedimentary basins were formed as pull-apart basins by the left-lateral faulting along the Red River fault and the Wang Chao faul due to the southeast movement with clockwise rotating by the India-Asia collision.

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The Mae Moh Group sedimentary rocks, Chiang Muan, Northern Thailand, host recent finds of the first Miocene hominoid fossils found in Southeast Asia. The age of these deposits is not well known except for Mammalian fossils that indicate deposition during the late Middle Miocene. We conducted a paleomagnetic analysis to establish magnetostratigraphy of the Mae Moh Group and increase the age resolution for these important deposits. Oriented minicore samples were drilled from nine horizons in this Group consisting of non-marine siltstones intercalated with coal layers. Thermal demagnetization of these cores indicates relatively stable remanences from five horizons, three of which are normal polarity and two reversed. Rock magnetic analyses indicate that titanomagnetite is the main magnetic carrier. We obtained a normal-reverse-normal polarity sequence, and correlated it to that from C5A to C5 chrons. This result suggests that the Mae Moh Group in Chiang Muan was deposited 12Ma to 10Ma, with a mean sedimentation rate of 4-10cm/ky.

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All living apes share Suspensory adaptations. Spool-shaped Numeral trochleae in apes have been considered as a specialization related to suspensory positional behaviors. While the humerus of Sivapithecus has a spool-shaped trochlea, its shaft is curved like non-hominoid anthropoids (e.g., cercopithecids). So-called Sivapithecus dilemma involves three kinds of question. Is a Sivapithecus-Pongo clade valid? Did Sivapithecus employ substantial suspensory positional behavior? Is the spool-shaped trochlea really originated from suspensory positional behavior? The author hypothesizes that Sivapithecus and Pongo form a clade and that Sivapithecus did not employ suspensory positional behavior (thus, the spool-shaped trochleae are not originated from suspensory behaviors and suspensory adaptations in living apes are results of parallel evolution). In living anthropoids, suspensory behavior (plus climbing) and pronograde quadrupedalism are the dichotomy of arboreal behavioral adaptation. Apes and some atelines engage in the former. However, it is probable that some Miocene apes including Sivapithecus can not be incorporated to this dichotomy and that orthograde climbing represented their basic positional adaptation.

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Great apes show a wide variety of social structure, including solitary life of orangutans, one/few-male group of gorillas, and multi-male-multi-female group of chimpanzees and bonobos. In recent studies for the understanding of such variations, much attention have been paid for the food distribution and foraging strategy of females. However, it seems difficult for the adaptation for dispersed distribution of fruit foods alone to explain the evolution of male philopatry and female transfer of African great apes. Adaptation to rain-forest environment of hominoid ancestors caused a very long interbirth interval, which resulted in an extremely high estrus sex ratio (number of adult males per adult female showing estrus). Together with the food distribution in the environment of each species, this estrus sex ratio explains various types of social structure of great apes, and provides an important insight on the evolution of social structure of early hominids.

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The feeding selectivity of Japanese macaques (Macaca fuscata) on plant foods was investigated at three levels; 1) species 2) vegetation types 3) plant patches, on Koshima Islet located in a warm-temperate region, southern Japan. The selectivity was evaluated using the Jacobs' index on the basis of feeding behavior and availability of plant resources at four seasons. At the species level, the selectivity calculated with feeding behavior through the year was highest for Myrica rubura. However, the most selected species at each season varied: Ficus erecta in February, Myrica rubura in June, Euscaphis japonica in September and Neolitsea sericea in November. Infrequent species, including deciduous pioneer trees, comprised those with high selectivity at a specific season. Vegetation types and plant patches were also selected differently at each season. Japanese macaques were taking calories at where not only one particular species but also multiple species were abundant. These results suggested that plant food diversity contributed to energy support for Japanese macaques in evergreen forest area through the year.

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Atlas bridging represents the formation of bony bridges over the vertebral artery groove of the first cervical vertebra. There are two types of bridging, “ponticulus posterior” and “ponticulus lateralis”. They may occur together or separately, and bilaterally or unilaterally.
We investigated frequencies of atlas bridging in 207 individuals of Japanese monkey from five regions. Sex differences are not significant in any population. Atlas bridging did not differ in frequency between right and left sides. As for the p. lateralis, the Shimane population has lower frequencies, and is significantly differrent from the Yakushima and Bousou (Chiba prefecture) populations.
However, in most of Japanese monkeys, cooccurrence of the posterior and lateral bridges appears to be the norm.

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Stone handling behaviour (SHB) has been observed among the free-ranging Arashiyama E troop of Japanese macaques (Macaca fuscata) in Kyoto, Japan, since 1979. For identifying the proximate factors of SHB, I analyse (1) the occurrence of SHB and the time change in the rate of stone-handlers, (2) the correlation of SHB with artificial feeding and stone-handlers' emotional states, and (3) the differences in post-provisioning behaviours between stone-handlers and non-stone-handlers.
Most SHB tended to occur after artificial feeding. The rate of stone-handlers in the troop increased rapidly, and reached a peak in 4 to 5 minutes after provisioning. Stone-handlers tended to be lower in dominance rank. During the post-provisioning period, they tended to (1) feed on less artificial food, but more natural food, (2) have less aggressive interactions, and (3) do more frequent self-scratching, than non-stone-handlers. These results indicate that stone-handlers are under a conflict situation between an unsatisfied feeding drive and an avoidance drive from aggressive interaction. This emotional conflict between feeding and aggression-avoidance drives is likely to be the main proximate factor of SHB.

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The distribution of wild Japanese macaques (Macaca fuscata) and crop damages caused by them in and around Shimagahara Village, where the intensive extermination was carried out in 1979 and 1980, were surveyed by interviewing the local people in 1999 and 2000. The macaque population had not yet recovered in Shimagahara Village. The troop exterminated was distributed at a distance less than 10km from the neighboring one.

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I discussed when the ancestor of the Japanese macaques. Macaca fuscata, immigrated into the Japanese Islands based on the Japanese macaque fossils and the land bridge formation between the continent and the Japanese Islands.
The land bridges were formed at least twice in the Quaternary of Japan. Their ages are at the oxygen isotope stage 16, 0.63 million years ago (Ma) when Stegodon orientalis immigrated into the Japanese Islands and the stage 12, 0.43Ma when Palaeoloxodon naumanni did.
To date, the purported oldest fossil macaque in Japan is the isolated lower third molar unearthed from the fissure sediment at the Ando Quarry, Yamaguchi Prefecture. The associated fossil proboscideans are S. orientalis and P. naumanni. The age of the macaque fossil, therefore, remains elusive. A humerus fossil was found from Yarimizu, Chiba Prefecture. The associated proboscidean fossil was P. naumanni. Then the ancestor of the Japanese macaques immigrated into the Japanese Islands between 0.63Ma and 0.43Ma. At present, we cannot discuss whether the ancestor of the Japanese macaques immigrated into the Japanese Islands before 0.63Ma because of the paucity of the evidence.

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