2015 Volume 123 Issue 2 Pages 99-105
In 1962, buried dog remains, believed to be the oldest in Japan, were excavated from the Kamikuroiwa Rock Shelter. The remain were lost, however, for nearly a half century until March 2011, when what appeared to be the bones of two Jomon dogs were found at Keio University, where extensive searches had been made over many years. While there were no specific notations on the bones, the name and date of the newspaper in which they were wrapped, remains of other animals packed with the dog bones, features of the limestone debris in the wrappings, and the dating of the dog bones all confirm that these are the missing dog remains from the Kamikuroiwa Rock Shelter. This recovery of the most ancient dog burials in Japan is significant for the study of domestic dogs in this country.
The skeletons of two dogs excavated in 1962 at the Kamikuroiwa Rock Shelter are well known as the earliest evidence of dog burial in Japan. Unfortunately, no detailed report was ever made on the find and the bones themselves went missing for nearly a half century after they were excavated. Three of the authors, Sato, Ando, and Abe, searched far and wide for them, and on 7 March 2011, discovered what appeared to be the bones of two dog skeletons in an archaeological storeroom on Keio University’s Mita campus. Other articles in this journal report on the age of these bones, their morphological characteristics (Komiya et al., 2015), as well as analyses of DNA (Masuda and Sato, 2015) and the results of radiocarbon dating (Gakuhari et al., 2015). In this article, the authors will go back to the conditions in which the dog bones were originally excavated from the Kamikuroiwa Rock Shelter, and explain why they are convinced they have rediscovered those remains.
The Kamikuroiwa Rock Shelter is located in the township of Kumakogen (formerly Mikawa-mura), Ehime Prefecture. The site is on the right bank of the Kuma River, whose source is on the southwest slope of Mt. Ishizuki (1982 meters above sea level), 3 kilometers upriver from where the Kuma and Omogo rivers merge (Figure 1). The mountain valley in which the site is located is also known by the name Yanase. Snow is common in the area in winter. The site consists of a limestone rock shelter jutting from the mountainside roughly 35 meters from the Kuma River at an elevation of 395–397 meters above sea level. The rock shelter is about 10 meters higher than the Kuma River.
Location of the Kamikuroiwa Rock Shelter (the map on the right is modified from Esaka et al., 1967).
This site was found in May 1961 by local landowners. It underwent five excavations under the direction of Teruya Esaka (currently professor emeritus, Keio University), in October 1961, July and October 1962, August 1969, and October 1970. Esaka uncovered numerous artifacts from the Incipient to Early Jomon periods, and the Kamikuroiwa Rock Shelter came to be known as a major archaeological site of the Jomon period.
Esaka’s excavations were carried out by expanding a trench dug along the cliff side. Numerous artifacts and faunal remains were unearthed in Area A at the far back end of the rock shelter (Figure 2). In particular, the bones of 28 humans excavated from the middle Initial Jomon layer, an estimate based on numerous shards of Oshigatamon pottery, are of critical importance in considering the provenance of the Jomon people (Harunari and Kobayashi, 2009).
Excavation area and location of dog burials (revised Figure 7 from Kobayashi, 2010).
According to Esaka and others involved in the excavations, the buried dog bones were unearthed southwest of the human burials, along the opening of the rock shelter (Figure 2, Esaka et al., 1967: 227). The exact location, however, is not certain. Excavation summaries published in 1967 and 1969 included drawings of excavation areas indicating the location of two sets of dog skeletons, but the locations were not the same in both papers (Esaka et al., 1967, 1969). Regrettably, there are no actual scale drawings of the dog skeletons. There are several photographs kept by the town of Kumakogen and Keio University, but the images are not clear. All that can be determined is that one set of skeletons appears to have been arranged for burial in a curved position (Figure 3).
One of the two dog burials excavated from the Kamikuroiwa Rock Shelter.
In their 1967 survey bulletin, Esaka and others expressed the opinion that the two dog skeletons, like the human remains unearthed in the same area, dated to the middle of the Initial Jomon period of Oshigatamon pottery, but they also noted that a small fragment of Todoroki pottery was on top of the dog bones (Esaka et al., 1967: 227). This point deserves special consideration in later discussion of dating the dog bones.
The two sets of dog skeletons found at Keio University in 2011 were not preserved in good condition. Many of the bones, including the skulls, were fractured at the time they were found in the Mita campus storeroom. After a simple reconstruction, it was determined that there were two nearly intact dog skeletons (Figure 4) with characteristics closely resembling those previously reported for Jomon dog skeletons. From this it was surmised that these bones came from prehistorical dog burials, but, unfortunately, there were no labels or other evidence to verify that the bones actually came from the dog burials of the Kamikuroiwa Rock Shelter, and nor was it clear from the available photographs. Nevertheless, there are several other items that prove the origins of the dog bones, and each is explained below.
Dog bones found at Keio University (upper photo: Dog 1, bottom: Dog 2).
When the authors made their discovery, their attention was caught, not only by the dog bones, but also by the newspaper used to wrap the bones, namely the 7 January 1962, morning edition of the Ehime Shinbun (Figure 5: Left). This regional paper was widely circulated in the area around the Kamikuroiwa Rock Shelter, and 1962 was the same year in which the Kamikuroiwa dog burials were excavated. The bones were found roughly wrapped in newspaper in two bundles, one marked ‘dog, large’ and the other, ‘dog, small.’ The newspaper bundle marked ‘dog, small’ also contained a tag marked, ‘1962, Area A, dog 1’ (Figure 5: Right). As has already been noted, the buried dogs were unearthed from Area A of the Kamikuroiwa Rock Shelter in 1962. Although the name of the archaeological site does not appear anywhere, the newspaper wrapping and tag are evidence that these are the dog bones excavated from the Kamikuroiwa Rock Shelter.
Newspaper wrapping and label.
The package of dog bones included the remains of other animals. In the wrapping labeled ‘dog, large,’ there were three marsh snail (Semisulcospira libertine) shells, and in the wrapping labeled ‘dog, small,’ there was one marsh snail shell and one third molar from the right maxilla of a Japanese deer (Cervis nippon). Also found, though it is not clear to which wrapping they belong, were 28 more marsh snail shells, the left femur of a young Japanese deer, and distal fragments of the middle phalanx of an adult Japanese deer. It is well known that numerous marsh snail shells and Japanese deer remains were unearthed in the occupational layers of the Kamikuroiwa Rock Shelter (Anezaki et al., 2009).
While there was no atlas vertebra among the bones marked ‘dog, small,’ there was an axis vertebra that perfectly matched an atlas vertebra taken from layer 4 of the Kamikuroiwa Rock Shelter. These items provide further evidence that the bones are the bones from the dog burials of the Kamikuroiwa Rock Shelter.
A significant amount of limestone debris were also found along with the marsh snail shells and Japanese deer bones included in the wrappings of the dog bones. Fortunately, one of the authors, Hashimoto, had, in 2005, visited the Second Rock Shelter located some 600 meters south-southwest of the Kamikuroiwa Rock Shelter, and had taken limestone samples. A thin section of 0.03 mm was taken from one of his limestone samples to compare with a 10 cm × 4 cm limestone fragment from the dog bone wrappings. The two samples were examined under a polarizing microscope to compare their constituent make-up and structural features (Figure 6).
Comparison of the limestone samples.
AMS 14C ages of the dog burials.
The results showed that the limestone in the dog bone wrappings and the limestone sample taken from the Second Rock Shelter contained virtually the same constituent minerals (Table 1), and shared the following features: (1) weak schistosity with weak preferred orientation of carbonate minerals in the matrix; (2) preferred orientation of muscovite and chlorite as accessory minerals, running parallel to the schistosity; and (3) distribution of vein-like pores aligned parallel or oblique to the schistosity.
○, large amount; Δ, small amount; +, very small amount; ±, extremely small amount.
All of these characteristics match the crystalline limestone found at the southern edge of the Sambagawa metamorphic belt, which encompasses the Kamikuroiwa Rock Shelter area (Momoi et al., 1991). These observations are more evidence that the bones discovered by the authors are those excavated from the Kamikuroiwa Rock Shelter.
The axies of the two dog skeletons were used for carbondating measurements. For both ‘dog, large’ and ‘dog, small,’ the carbon date ranged between c. 7400 and 7300 cal BP, indicating that the bones probably date from the end of the Initial to the beginning of the Early Jomon periods (Gakuhari et al., 2015). This makes them, of course, the oldest buried dog bones recovered on the Japanese archipelago, but it would date the remains later than previously thought as the Kamikuroiwa Rock Shelter dog burials are assumed to date back to the middle of the Initial Jomon period.
As previously noted, at the time of the excavation, a Todoroki pottery shard was found on top of the dog remains. If this is a Todoroki A-type fragment, and we accept that the dog burials must have taken place around the same time as the prevalence of this pottery, then the presence of the shard and the carbon-dating of the bones both corroborate the assertion that the dog bones found wrapped in newspaper were excavated from the Kamikuroiwa Rock Shelter.
Given the above evidence, there is no doubt that the dog bones found in the Mita campus storeroom are the very same bones excavated from the Kamikuroiwa Rock Shelter. It is of great significance that these dog bones, long considered the oldest example of dog burial in Japan, have at last been rediscovered.
The dog has long been a domesticated animal with a rich diversity of ancestry, characteristics, uses, and methods of care. To garner this kind of information from excavated bones requires joint interdisciplinary research involving not only morphology, but also dating technology, genetics, and a deep understanding of bone chemistry. There are only a few examples of this kind of research in Japan, which serves to further highlight the diverse and integrated approach taken by the authors in their study of the most ancient dog burials recovered in Japan. It is the authors’ hope that these findings on the morphological characteristics, age, and dietary habits of the Kamikuroiwa dog remains will promote further studies on the history of the domesticated dog in Japan.
The authors would like to express thanks to Nobuo Shigehara for his invaluable advice, and to Toyohiro Nishimoto and Akira Matsui for their support and assistance. This research was made possible with the following funding: (i) Keio University Matsunaga Memorial Fund for the Research of Cultural Assets ‘Research of Buried Dog Remains in the Initial Jomon Period’ (Principal Researcher: T. Sato); (ii) JSPS Core to Core Program (Advanced Research Networks) ‘Advanced Core Research Center for the History of Human Ecology in the North’ (Principal Researcher: H. Kato).