taxonID	type	description	language	source
0388F00ED717FF94F596D89BFCBD90A2.taxon	description	Rt occurs in human settlements and agricultural areas (its scientific name tanezumi means ‘ ricefield rat’ in Japanese), but also in forests on all main islands of Japan except Hokkaido, and on many smaller islands where it is often the most abundant non-volant forest mammal (see Results). However, Rt in Japan has only been studied in urban and agricultural habitats, with the exception of very cursory studies of forest populations in southern Ryukyu Islands (see bibliography in Iwasa 2015 c).	en	Dinets, Vladimir, Asada, Keishu (2021): Noble savages: human-independent Rattus rats in Japan. Journal of Natural History 54 (37 - 38): 2391-2414, DOI: 10.1080/00222933.2020.1845409, URL: http://dx.doi.org/10.1080/00222933.2020.1845409
0388F00ED716FF95F596DAA2FCBC92E1.taxon	description	Rn is a native species in the main islands of Japan: there are Middle Pleistocene fossils (pre-dating the human arrival) from Honshu, as well as Late Pleistocene – Holocene fossils from Honshu and Kyushu (Kawamura 1989; Iwasa 2015 b). Elsewhere the earliest fossils are from the Late Pleistocene of Korea (Yeong-Seok 2015) and the Late Pleistocene of central China (Zheng 1993). Today Rn occurs on all four main islands of Japan and on Tsushima (Iwasa 2015 b). It is also present on almost all other islands of Japan (with the notable exception of Amami-oshima), but those populations are purely human-associated and presumably introduced (Iwasa 2015 b); the extensive fossil record from the central and southern Ryukyu Islands shows that Rn arrived there much later than humans (Otsuka and Takahashi 2000). It largely replaced R. rattus in European cities during the Industrial Revolution (Amori and Cristaldi 1999), and in North American cities in the eighteenth century (Lack et al. 2013), but it is unknown whether a similar replacement of Rt by Rn has ever taken place in the cities of the main Japanese islands; in parts of China and certain other regions, the opposite might be happening (Zhang et al. 2000). Some field zoologists have always recognised Rn, Japan’s only somewhat aquatic native rodent, as an integral element of the country’s native fauna (Abe et al. 1971), but the Japanese zoological literature often treats it as an invasive species confined to human settlements and agricultural habitats (see e. g. Iwasa 2015 b), despite the fact that it has been recorded during surveys in remote mountain forests and large natural wetlands on Hokkaido (Ota 1968; Abe et al. 1971; Maekawa et al. 2002).	en	Dinets, Vladimir, Asada, Keishu (2021): Noble savages: human-independent Rattus rats in Japan. Journal of Natural History 54 (37 - 38): 2391-2414, DOI: 10.1080/00222933.2020.1845409, URL: http://dx.doi.org/10.1080/00222933.2020.1845409
0388F00ED71FFF9DF596DB6DFB0C90BC.taxon	description	On Honshu, one individual was observed for ~ 5 min in August in a relict grove of giant Japanese horse chestnuts (Aesculus turbinata) at Torii Pass (Figure 2); it repeatedly carried large rounded objects (presumably horse chestnuts) from the crown of a very large tree to a hollow ~ 20 cm in diameter, ~ 4 m above the ground. Another Rt was observed in September climbing a large oak (Quercus sp.) in Kasuga Primaeval Forest near Nara (the oldest forest in Japan). A trackway was found on fresh snow in Yacho-no-Mori deciduous forest near Karuizawa, but that location was within 100 m of residential buildings. On Shikoku, three Rt were observed in August in Hokigamine Forest Park near Kochi, in a habitat transitional between subtropical evergreen and deciduous forest (Hämet-Ahti et al. 1974). Two of them were moving through subcanopy tree crowns 4 – 5 m above the ground, while the third was feeding on acorns (Quercus sp.) on the ground. On Kyushu, Rt was surprisingly common (eight sightings in two nights) in subtropical evergreen forests around Bonotsu in the far south of the island (Figures 3, Figures 4); all animals were observed in tall shrubs or subcanopy trees 1 – 3 m above the ground. In the Ryukyu Islands, Rt was abundant year round in all surveyed forests on Amami- Oshima, Miyakojima and Ishigaki Islands. On Okinawa it was common in small forest fragments in the south but virtually absent from larger forests in central and northern parts of the island, such as Yanbaru National Park. On Iriomote it was apparently rare in natural habitats and confined to forest edges. We also recorded it in remnant forest patches on Ie-jima, Kume-jima, Minami-Daito and Yonaguni, but not on Tokunoshima, Yakushima or Iheya-jima. More than 2 / 3 of all sightings (N = 137) were in trees. Many rats were observed feeding; identified food items included acorns (Quercus sp.), fruit of itajii (Castanopsis sieboldii), figs (Ficus sp.), and a cave cricket (Rhaphidophoridae). Rt was never found in Ryukyu pines (Pinus luchuensis) or pine-dominated forests that are common on the islands. Rt was common in forests of Chichijima and Hahajima (Ogasawara Islands); all observed animals (N = 13) were in trees 1 – 5 m above the ground. The only identified food item was a fig (Ficus sp.). Exposed arboreal nests, like those known for Rt in the Philippines (Stuart et al. 2012) and for R. rattus in the Caucasus region (Bernstein 1959) and North America (Reid 2006), were never observed, but 11 animals on Ryukyu and Ogasawara Islands were observed entering and / or exiting tree hollows. All such hollows had entrances 9 – 25 cm in diameter and were located 2 – 4 m above the ground, in trees that were 30 – 60 cm in diameter at ~ 1.5 m above the ground.	en	Dinets, Vladimir, Asada, Keishu (2021): Noble savages: human-independent Rattus rats in Japan. Journal of Natural History 54 (37 - 38): 2391-2414, DOI: 10.1080/00222933.2020.1845409, URL: http://dx.doi.org/10.1080/00222933.2020.1845409
0388F00ED719FF98F596D9DDFC519350.taxon	description	On Hokkaido, we found two trackways in March and observed one animal (Figure 5) in August in Kushiro Marsh, the largest remaining natural wetland in Japan. All three records were along the edges of wood patches surrounded by reedbeds, tall grass and patches of open water (Figure 6). One trackway was found in March in Kiritappu Marsh (a similar but smaller wetland) in a large reedbed ~ 50 m from the edge of mixed forest. We also found one trackway in December on a snow-covered beach in Shiretoko National Park, but it was less than 1 km from residential buildings. That trackway appeared to be a well-used path ~ 30 m long, connecting a burrow in the coastal cliff with intertidal zone, where more than a hundred fragments of broken shells of periwinkles (Littorinidae) were scattered among the rocks. The intertidal zone in this area also had numerous limpets, crabs, sea stars, sea urchins, kelp plants, and other possible food items. In Daisetsuzan National Park we found one trackway in March in riparian forest of birch (Betula sp.) (Figure 7), and observed one animal in August as it was feeding on Geometridae moths on a paved road through oldgrowth mixed montane forest (Figure 8), near a small stream lined with alder (Alnus sp.). The moths were flying in great numbers that night, and covered the road pavement at densities of up to 3 moths per 1 m 2 of the road (visual estimate). Numerous other mammals, birds and amphibians were also feeding on them. On Honshu and Kyushu Rn was recorded only in wetlands. On Honshu, at least six individuals were seen in June walking and feeding (on unidentified small seeds) along the edges of reedbeds of Tone River near Sasagawa, one was observed in August running across an opening in a small wetland on Niigata Plain, and 12 were seen in December running and swimming in flooded woodlands along the shores of Lake Biwa. However, all those locations were within 1 km of residential buildings and / or ricefields. On Kyushu, one Rn was seen in December running across a sedge meadow in Bogatsuru Marsh, a unique high-elevation wetland inside a volcanic crater in Aso-Kuji National Park. On Tsushima, two Rn were observed in August feeding on crabs in the intertidal zone in Aso Bay Park, along a shoreline lined with deciduous forest and wetlands (Figure 9). One was seen entering a burrow in a steep clay slope ~ 3 m from the water edge at high tide; the burrow had likely been built by the rat, as similar waterside burrows are commonly built in riverbanks by human-independent Rn in Russian Far East (Kuzyakin 1951). Local people reported rats to be common along the island’s coast.	en	Dinets, Vladimir, Asada, Keishu (2021): Noble savages: human-independent Rattus rats in Japan. Journal of Natural History 54 (37 - 38): 2391-2414, DOI: 10.1080/00222933.2020.1845409, URL: http://dx.doi.org/10.1080/00222933.2020.1845409
0388F00ED71BFF84F596DFD5FED396C5.taxon	description	Localised distribution of Rt in natural habitats on the main islands of Japan likely results from the loss of high-quality habitat in the suboptimal northern part of the range, and small extent of warmer areas (characterised by subtropical evergreen forest) where it can live in lower-quality habitat. It might be speculated that following the widespread logging during the Edo Period (Morris-Suzuki 1995) it was replaced in much of its former range by two species of large native mice (Apodemus specious and A. argenteus) which are capable of living at high densities in all forest types and are by far the most abundant forest rodents on the main islands of Japan (Ohdachi et al. 2015; also VD pers. obs.). Alternatively, the present range of Rt in natural habitats might be confined to areas where non-coniferous forests survived during the last glacial maximum (Tsukada 1985). It is also possible that all Rt present in Japan today originate from an ancient introduction rather than from the Pleistocene rats, which may have been driven to extinction by ice ages and / or the massive Akahoya Eruption, which covered much of southern Japan with volcanic ash in 4500 BC (Maeno and Taniguchi 2005). Small human-independent populations of Rt on the main islands of Japan might be under threat from feral cats and introduced Siberian weasels (Mustela sibirica), northern raccoons (Procyon lotor) and masked palm civets (Paguma larvata) (Ohdachi et al. 2015). Hybridisation with introduced R. rattus has been recorded in some Japanese cities and small islands (Chinen et al. 2005; Kambe et al. 2013) and might eventually threaten the genetic integrity of native populations. On some of the Ryukyu Islands, Rt is now the most common non-volant forest mammal, and an important food source for endangered Iriomote cat (Prionailurus bengalensis iriomotensis) (Sakaguchi and Ono 1994). Its rarity in northern Okinawa might be a result of mongoose eradication programme that started in 2000 (Yamada et al. 2015), as thousands of Rt per month were caught in mongoose traps and removed (Kambe et al. 2012); however, a similar programme on Amami-oshima does not seem to have had such an effect. The distribution of Rt in natural habitats in its presumed native range in mainland Asia is difficult to elucidate from the published literature. It is usually unclear which populations are human-independent because, as in Japan, it is often impossible to find forests with no human settlements nearby (Lekagul and McNeely 1977). Another problem is the complicated and rapidly evolving taxonomy of R. rattus sensu lato; in many cases multiple taxa with different habitat preferences are mentioned but it is unclear what exactly they are. Some mainland Rt differ from Japanese animals phenotypically. In China they often have yellowish spots on the throat, and are considered to be two separate species – R. fulvipectus (Milne-Edwards, 1872) and R. yunnanensis (Anderson, 1879) – by many Chinese zoologists; these forms are treated as subspecies or synonyms in non-Chinese literature (Ying et al. 2002; Musser and Carleton 2005), and have identical karyotypes (Mikhail Kosoy pers. comm.). Yellowish throat spots are common in some Indochinese populations of Rt as well (Abramov et al. 2007). In mainland Asia and elsewhere Rt is mostly confined to human-modified habitats (Zhan 1982; Zhang et al. 2000; Stuart et al. 2012). In Korea it occurs in forests on small Ulleung Island (VD pers. obs.), but not on larger Jeju Island or the mainland (Jo et al. 2012, 2018). In China it is largely absent from forests as far south as Hong Kong (Chung and Corlett 2006) and Taiwan (Yu 1994). However, in southernmost China (Yunnan and Guanxi) and northern Indochina, where Rt is apparently native (Guo et al. 2019), it is an uncommon but widespread component of forest fauna (Zhang et al. 2000). At the northern edge of its native range in China it occurs at low densities in primary montane subtropical forests of central Yunnan, where the habitat is remarkably similar to the sites where we found it on Honshu (Wu and Deng 1988; Wenbo Chen pers. comm.; VD pers. obs.). Rt also occurs at low densities in evergreen tropical forests of southern Yunnan, where animals in primary and secondary forest are phenotypically different (Wu et al. 1996), and in deciduous tropical forests and karst forests in northern Thailand (Chaisiri et al. 2010; Latinne et al. 2011). Note that we found it in karst forests in Okinawa (Table 1). Rt is apparently absent from forests in mainland Vietnam (Lunde and Truong Son 2001); no Rt were recorded during an extensive camera trapping survey of primary forests of Pu Mat National Park in north-central Vietnam (VD and Nicholas Wilkinson, in prep.). Rattus rattus sensu lato has been reported to be common in primary forests on islands off southern Vietnam (Abramov et al. 2007), in karst and mangrove forests of southern Thailand (Lekagul and McNeely 1977; Latinne et al. 2011), and in other natural (but mostly disturbed) habitats of southern Indochina (Lekagul and McNeely 1977; Aplin et al. 2011); these populations are currently thought to be taxa different from R. tanezumi sensu stricto, based on mtDNA and sometimes phenotypical differences (Van Peenen et al. 1970; Pagès et al. 2010; Aplin et al. 2011; Balakirev and Rozhnov 2012; Abramov et al. 2018), but nuclear DNA data contradict this (Pagès et al. 2013). Some forms of R. rattus sensu lato, possibly Rt, are common in disturbed forests of Laos (Aplin and Singleton 2003) and unlogged forests of Myanmar (Thazin Wai et al. 2018). Unlike R. rattus sensu stricto, Rt is not known from natural habitats outside Asia; all records from other continents are from human settlements (Aplin et al. 2011; Bastos et al. 2011; Lack et al. 2012).	en	Dinets, Vladimir, Asada, Keishu (2021): Noble savages: human-independent Rattus rats in Japan. Journal of Natural History 54 (37 - 38): 2391-2414, DOI: 10.1080/00222933.2020.1845409, URL: http://dx.doi.org/10.1080/00222933.2020.1845409
0388F00ED707FF85F596DB06FC40942A.taxon	description	It is puzzling that Rn occurs in forests of Hokkaido but not in the mountains of Honshu where the climate is similar; possible explanations include the availability of invertebrate prey or the duration of snow cover, which is important for Rn in the forests of Russian Far East (Kuzyakin 1951). It is also possible that Rn of Hokkaido are not related to those known from Pleistocene fossils from Honshu and Kyushu, but have colonised Hokkaido from mainland Asia via Sakhalin Island, like most other native mammals of Hokkaido (Kuroda 1939). Unfortunately, the Pleistocene fossil record of small mammals from Hokkaido is very fragmentary (Kawamura 1991). Similarly, Rn of Tsushima might be relatively recent natural colonisers from Korea, like some other mammals of the island (Ohdachi et al. 2015). Their dependence on wetlands and pristine forests make human-independent populations of Rn vulnerable to extinction in Japan, where virtually all primary forests were logged during the Edo Period (Morris-Suzuki 1995), and very few large natural wetlands remain, particularly outside Hokkaido (Washitani 2007). Daisetsuzan National Park (the largest protected natural area in Japan) and Kushiro-Shitsugen National Park (the largest remaining wetland in the country), where Rn was detected by previous surveys (Ota 1968; Abe et al. 1971) as well as in our study, appear to be the main strongholds of human-independent Rn in Japan. Populations in Hokkaido wetlands might be under threat from introduced American mink (Neovison vison), while on other main islands they now have to compete with introduced coypu (Myocastor coipus) (Ohdachi et al. 2015). Declines in human-independent populations of Rn have been noted in other parts of its native range: it is now virtually extinct in Transbaikalia where it was locally common in the twentieth century (Karaseva et al. 1990), and on some of the southern Kuril Islands where it used to be abundant (Grigor’ev 2008). Replacement of native subspecies caraco by invading ssp. norvegicus from the west has been noted in Siberia (Kuzyakin 1951), and might be happening in Japan, where differences in mtDNA between brown rats in ports / large cities and the backcountry have been reported (Ohno et al. 1994). In its presumed native range outside Japan, Rn occurs in upland forests (mostly alder groves along streams), riparian forests, tallgrass floodplain meadows, and seashore habitats on southern Kuril Islands, where virtually all bodies of water once had Rn living along their shores (Surkov 1986; Dinets and Rotshild 1998); in mixed forests (particularly with alder) and tallgrass meadows near streams on Sakhalin Island (Surkov 1986); in floodplain and streamside forests (sometimes in pristine areas very far from human habitat) in Ussuriland (Maak 1861; Karaseva et al. 1990; Anna Gritsuk pers. comm.; Anastasia Kadetova pers. comm.); along forest streams with large salmon runs in the lower Amur River basin (Khamaganov 1965); in riparian forests and sedge-reed marshes around oxbow lakes in Transbaikalia (Radde 1862; Kuzyakin 1951; Karaseva et al. 1990); in reedbeds with forested islands in Manchuria (VD pers. obs.), and in coastal wetlands in Korea (VD pers. obs.). Note that the oldest Ussuriland record is from the mid-nineteenth century when there were no cities or agriculture there (Maak 1861); there are also mid-nineteenth century records from Sakhalin, where human presence at the time was largely limited to small villages of native hunter-gatherers (Yegerov 1946). In its non-native range in western Eurasia and North America Rn also readily colonises reedbeds, riverbanks and other wetlands, and sometimes deciduous forests and seashores (Kuzyakin 1951; Karaseva et al. 1990; Amori and Cristaldi 1999; Dinets 2015; KryŠtufek et al. 2020).	en	Dinets, Vladimir, Asada, Keishu (2021): Noble savages: human-independent Rattus rats in Japan. Journal of Natural History 54 (37 - 38): 2391-2414, DOI: 10.1080/00222933.2020.1845409, URL: http://dx.doi.org/10.1080/00222933.2020.1845409
