{{Short description|Subspecies of mammal}} {{EngvarB|date=June 2022}} {{Use dmy dates|date=June 2022}} {{Subspeciesbox | name = Ezo flying squirrel | image = Wiki-ezomomonga1.jpg | image_caption = In Higashikawa (March 2009) | status = | status_system = | status_ref = | genus = Pteromys | species = volans | species_link = Siberian flying squirrel | subspecies = orii | authority = (Kuroda, 1921) | synonyms = ''Sciuropterus russicus orii''<ref name="Kuroda"/><br>''Pteromys orii''<ref name="Ellerman"/><br>''Pteromys volans orii''<ref name="EMS"/> | range_map = | range_map_caption = }}
The '''Ezo flying squirrel''' ('''''Pteromys volans orii''''') or ''Ezo-momonga'' ({{langx|ja|エゾモモンガ}}) is a subspecies of the Siberian flying squirrel. It is endemic to Hokkaidō, Japan, part of the region once known as Ezo. In the legends of the local Ainu, the Ezo flying squirrel or ''A-kamui'' ({{langx|ain|アッ・カムイ}}) is a tutelary deity of children.<ref name="WMJ">{{cite book |title=The Wild Mammals of Japan |editor1=Ohdachi, S.D. |editor2=Ishibashi, Y. |editor3=Iwasa, M.A. |editor4=Fukui, D. |editor5=Saitoh, T. |edition=2 |publisher=Shoukadoh and The Mammal Society of Japan |year=2015 |isbn=978-4879746917 |pages=204–205}}</ref> Together with the Ezo chipmunk (''Eutamias sibiricus lineatus'') and {{ill|Ezo squirrel|ja|エゾリス}} (''Sciurus vulgaris orientis''), it is one of the three sciurids (members of the squirrel family (Sciuridae)) found on the island, to the north of Blakiston's Line, each having its own particular ecological niche.<ref name="Obihiro">{{cite web |url=https://www.obihiro.ac.jp/wp/wp-content/uploads/2020/07/cf99469518523213bf52f363162ae2ed.pdf |script-title=ja:エゾモモンガってどんな動物? |trans-title=What kind of animal is the Ezo Momonga? |language=ja |publisher=Obihiro University of Agriculture and Veterinary Medicine |access-date=26 May 2022}}</ref><ref name="Heibonsha">{{cite book |chapter=エゾモモンガとニホンモモンガ |author=Yanagawa Hisashi 柳川久 |script-title=ja:『日本動物大百科 第1巻 哺乳類 I』 |trans-title=The Encyclopaedia of Animals in Japan I: Mammals I |lang=ja |editor=Kawamichi Takeo 川道武男 |editor-link=:ja:川道武男 |publisher=Heibonsha |year=1996 |isbn=978-4-582-54551-7 |pages=84–87}}</ref>
==Taxonomy== [[File:Hyōjirō Orii 折居彪二郎.jpg|thumb|left|150px|Specimen collector Orii Hyōjirō in Taishō 2 (1913)]]
The Ezo flying squirrel was first described by Nagamichi Kuroda in 1921, as ''Sciuropterus russicus orii''.<ref name="Kuroda">{{cite journal |url=https://www.biodiversitylibrary.org/page/52845483 |title=On three new mammals from Japan |author=Kuroda, N. |journal=Journal of Mammalogy |volume=2 |issue=4 |pages=208–211 |year=1921 |doi=10.2307/1373554|jstor=1373554 }}</ref> In 1940, John Reeves Ellerman elevated the Ezo flying squirrel to species rank and transferred it to the genus ''Pteromys'', the new combination being ''Pteromys orii''.<ref name="Ellerman">{{Cite book |year=1940 |title=The families and genera of living rodents |url=https://www.biodiversitylibrary.org/page/8414701 |volume=I: ''Rodents Other than Muridae'' |location=London |publisher=British Museum (Natural History) |page=294}}</ref> In 1951, Ellerman and Morrison-Scott again treated the Ezo flying squirrel as a subspecies of the Siberian flying squirrel, under the combination ''Pteromys volans orii''.<ref name="EMS">{{Cite book |last1=Ellerman |first1=J. R. |author-link1=Sir John Ellerman, 2nd Baronet |last2=Morrison-Scott |first2=T. C. S.|author-link2=Terence Morrison-Scott |url=https://www.biodiversitylibrary.org/page/8722768 |title=Checklist of Palaearctic and Indian mammals 1758 to 1946 |year=1951 |publisher=British Museum (Natural History) |place=London |page=467}}</ref><ref name="gliding">{{cite journal |last1=Jackson |first1=S.M. |last2=Thorington |first2=R. W. Jr. |title=Gliding Mammals: Taxonomy of Living and Extinct Species |url=https://figshare.com/articles/Gliding_Mammals_Taxonomy_of_Living_and_Extinct_Species/9762035 |journal=Smithsonian Contributions to Zoology |year=2012 |issue=638 |publisher=Smithsonian Institution |doi=10.5479/si.00810282.638.1 |page=71}}</ref> The subspecific name honours Orii Hyōjirō, collector of the type specimen in {{nihongo|"Uyenai"|植苗}} (now part of the city of Tomakomai), old Iburi Province, on 13 March 1920.<ref name="Kuroda"/>
==Description== The Ezo flying squirrel is a small arboreal rodent with a white belly and a back and tail that is dark brown in summer and is grey-brown in winter. Around the eyes, there is a ring of dark brown fur. Males are slightly longer in length than females, with male's body length being {{convert|16|to|18|cm|abbr=on}}, and females about {{convert|15|cm|abbr=on}}. The length of the body from head to tail is on average {{convert|30|cm|abbr=on}} together. Tail length ranges from {{convert|9.2|to|11.8|cm|abbr=on}}, the hind feet (excluding claws) from {{convert|3.2|to|3.65|cm|abbr=on}}, and the ears from {{convert|1.75|to|2.15|cm|abbr=on}}. The body weight ranges from {{convert|62|to|123|g|abbr=on}} (n=22).<ref name="WMJ"/>
==Distribution and habitat for living== While the Siberian flying squirrel (''P. volans'') at species level may be found across the coniferous forest zone from Finland and the Baltic to Korea, the Hokkaidō population is recognized as a distinct, endemic subspecies.<ref name="WMJ"/> On Hokkaidō, it inhabits the coniferous, broad-leaved deciduous, and mixed forests, both montane and lowland, and may also be found in windbreaks and groves in urban parks.<ref name="WMJ"/><ref name="Obihiro"/> Males may range over an area of some {{convert|2.2|to|4.8|ha}}, while the home range of females is typically around {{convert|1.7|ha|abbr=on}}. In Furano, population density has been estimated at two individuals per hectare.<ref name="WMJ"/>
==Behaviour and ecology== The Ezo flying squirrel is nocturnal, typically leaving the nest to forage several times a night, from 15–20 minutes after sunset to 20–25 minutes before sunrise.<ref name="WMJ"/><ref name="Obihiro"/> It does not hibernate, but activity beyond the nest is reduced during winter; squirrels emerge once a day for food around daybreak.<ref name="Obihiro"/> Lifespan in the wild rarely exceeds three years, but captive specimens can live for four or five years.<ref name="WMJ"/>
===Locomotion=== In a study of thirty-one squirrel glides in Obihiro, there was a mean horizontal gliding distance of {{convert|18.90|m}}, horizontal distances ranging from {{convert|4.30|to|49.40|m}}. The mean glide ratio (calculated as horizontal distance travelled divided by vertical descent) was 1.70, with again a wide range of values, glide ratios ranging between 0.48 and 3.31. While the females were heavier than the males, there was no significant sex- or weight-related difference in glide distances or ratios.<ref name="glides">{{cite journal |author1=Asari, Y. |author2=Yanagawa, H. |author3=Oshida, T. |year=2007 |title=Gliding ability of the Siberian flying squirrel ''Pteromys volans orii'' |url=https://www.researchgate.net/publication/232676054 |journal=Mammal Study |volume=32 |pages=151–154 |doi=10.3106/1348-6160(2007)32[151:GAOTSF]2.0.CO;2 |s2cid=59025388 |number=4}}</ref>
===Diet and predation=== [[File:Wiki-ezokuroten5.jpg|thumb|right|175px|Remains of Ezo flying squirrels are sometimes found in {{ill|Ezo sable|ja|エゾクロテン}} droppings<ref name="WMJ"/>]] The Ezo flying squirrel is entirely herbivorous, feeding on leaves, buds, flowers, seeds, acorns, catkins, and fruits of both broad-leaf trees and conifers, with significant seasonal variation.<ref name="WMJ"/><ref name="food">{{cite journal |script-title=ja:野外観察によって確認されたエゾモモンガの採食物 |trans-title=Field observations of the food items of the Siberian flying squirrel, ''Pteromys volans orii'' |language=ja, en |author1=Asari, Y. |author2=Yamaguchi, Y. |author3=Yanagawa, H. |journal=Journal of the Japanese Wildlife Research Society |year=2008 |volume=33 |pages=7–11 |doi=10.18987/jjwrs.33.0_7}}</ref> In spring, young leaves form a major part of the diet, including those of willows (''Salix'' spp.), Japanese white birch (''Betula platyphylla''), and East Asian alder (''Alnus japonica''); in summer, cherries, mulberries, birch and maple seeds, and the unripe acorns of the daimyō oak (''Quercus dentata'') and Mongolian oak (''Quercus crispula''); prior to winter, in order to put on weight—and increase the chance of survival—there is increased foraging of highly nutritious pine nuts; during the winter, birch and alder leaves and buds are consumed.<ref name="WMJ"/><ref name="Obihiro"/><ref name="food"/>
Predators include the Ezo red fox (''Vulpes vulpes schrencki''), {{ill|Ezo sable|ja|エゾクロテン}} (''Martes zibellina brachyura''), Ural owl (''Strix uralensis''), Blakiston's fish owl (''Bubo blakistoni''), sparrowhawk (''Accipiter nisus''), black kite (''Milvus migrans''), and domestic cat (''Felis catus'').<ref name="WMJ"/><ref name="Heibonsha"/>
===Nesting=== Nests are in tree hollows and, on occasion, man-made bird boxes.<ref name="Obihiro"/> A study of thirty-six winter nests found Sakhalin fir (''Abies sachalinensis'') was the preferred choice (52.8%), followed by the painted maple (''Acer pictum'' subsp. ''mono''), Erman's birch (''Betula ermanii''), Mongolian oak (''Quercus mongolica'' var. ''grosseserrata''), prickly castor oil tree (''Kalopanax septemlobus''), and Japanese walnut (''Juglans ailantifolia''). The holes used for nests, most of which were located at least {{convert|10|m}} up the tree, heights ranging from {{convert|1|to|12|m}}, had typically originally been excavated by woodpeckers, or coincided with knots, frost cracks, and areas damaged by tree fungus.<ref name="nests">{{cite journal |author1=Nakano, S. |author2=Hino, T. |author3=Natsume, S. |author4=Hayashida, M. |author5=Inaba, Y. |author6=Okuda, A |year=1991 |script-title=ja:冬季におけるエゾモモンガ''Pteromys volans orii''の営巣木の特徴と巣穴の構造 |trans-title=Notes on Nesting Trees of Japanese Flying Squirrel, ''Pteromys volans orii'', in Hokkaido during Winter |journal=Research Bulletin of the Hokkaido University Forests |language=ja, en |publisher=Hokkaido University |volume=48 |issue=1 |pages=183–190 |hdl=2115/21336}}</ref> To line the nest, the finely shredded inner bark of vines such as ''yama-budō'' (''Vitis coignetiae'') and dry moss are used.<ref name="Obihiro"/><ref name="nests"/> Repurposed nests include those of the great spotted woodpecker (''Dendrocopos major''), Oriental turtle dove (''Streptopelia orientalis''), and members of the crow family (Corvidae).<ref name="Obihiro"/> In winter, deeper holes are preferred, and three to five individuals may share a single nest, to help keep warm.<ref name="WMJ"/><ref name="Obihiro"/>
===Reproduction=== There are two mating seasons, the first in late February/early March (with birth from the middle of April to early May), the second in June (with birth from late July to the middle of August). During this time, females have their own territory, while males overlap with each other and with more than one female.<ref name="WMJ"/> The litter size averages 3.3 kittens, ranging from two to six.<ref name="WMJ"/><ref name="Obihiro"/> Kittens weigh {{convert|3|to|4|g}} at birth and are red and hairless, their eyes and ears closed. Their digits, initially joined together, begin to separate one-by-one after ten to twelve days. Teeth in the lower jaw begin to appear after twenty days, and a week or so later in the upper jaw. Around thirty days after birth, the whole body is covered with fur. After 35 days, the eyes open. Movement of the back legs develops later than that of the front legs, after around twenty days; from around 28 days, kittens are able to walk using all four limbs. Approximately 40 days after birth, young leave the nest for the first time and begin to consume solid food. After around 50 days, kittens start to practise gliding.<ref name="Obihiro"/> Young squirrels leave the nest and their parents around 60 days after birth.<ref name="WMJ"/><ref name="Obihiro"/>
==Conservation== The Ezo flying squirrel is classed as a protected (rather than game) species.<ref name="WMJ"/> Forest fragmentation has been identified as a threat due to their method of locomotion.<ref name="glides"/>
==Ainu culture== [[File:John Batchelor b.jpg|thumb|upright|Missionary John Batchelor documented the importance of the flying squirrel to the Ainu<ref name="Ainu">{{cite book |author=Batchelor, John |url=https://wellcomecollection.org/works/e8hd3nfn |title=The Ainu and their Folk-lore |publisher=Religious Tract Society |year=1901 |place=London |pages=339–341}}</ref>]]
According to John Batchelor's account of the folklore of the Ainu of Hokkaidō, the flying squirrel—of the three Japanese flying squirrels, the Japanese giant flying squirrel (''Petaurista leucogenys''), Japanese dwarf flying squirrel (''Pteromys momonga''), and Ezo flying squirrel, the last is the only one to be found north of Blakiston's Line<ref>{{cite book |title=The Wild Mammals of Japan |editor1=Ohdachi, S.D. |editor2=Ishibashi, Y. |editor3=Iwasa, M.A. |editor4=Fukui, D. |editor5=Saitoh, T. |edition=2 |publisher=Shoukadoh and The Mammal Society of Japan |year=2015 |isbn=978-4879746917 |pages=200–205}}</ref>—was known as ''At-kamui'' or "the Divine prolific one", due to the belief that it could produce up to thirty young in one litter, and regarded as a bird, since it could fly. Where an Ainu man and his wife were childless, and initial appeal to the goddess of fire and her consort was to no avail, the husband, without his wife's knowledge, should go into the mountains to hunt for a flying squirrel, which he should then cut into small pieces, boil, and place upon a tray. Using Inau sticks, and praying to the sacrificed squirrel for assistance, he should give the meat to his wife to eat, again without her knowing from what "bird" it was derived. Only if this feast, known as ''uatama marapto'' or "the feast of placing the prolific one", proved unsuccessful should he resort to taking a second or third wife.<ref name="Ainu"/>
==See also== * List of mammals in Japan * Japanese Red List * Japanese dwarf flying squirrel {{Clear}}
==References== {{Reflist|30em}}
== External links == * {{Commons category inline|Pteromys volans orii}}
{{Taxonbar|from=Q20903686}}
Category:Endemic mammals of Japan Category:Environment of Hokkaido Category:Mammals described in 1921 Category:Taxa named by Nagamichi Kuroda Category:Pteromys Category:Ainu culture