{{short description|Species of "beautiful" squirrel from Southeast Asia}} {{Speciesbox | name = Finlayson's squirrel | image = Callosciurus finlaysonii - Finlayson%27s squirrel (variable squirrel).jpg | image_caption = ''C. f. bocourti'' in Bangkok, Thailand | status = LC | status_system = IUCN3.1 | status_ref = <ref name="iucn status 12 November 2021">{{cite iucn |author=Duckworth, J.W. |date=2017 |title=''Callosciurus finlaysonii'' |volume=2017 |article-number=e.T3596A22254494 |doi=10.2305/IUCN.UK.2017-2.RLTS.T3596A22254494.en |access-date=12 November 2021}}</ref> | genus = Callosciurus | species = finlaysonii | authority = (Horsfield, 1823) | range_map = Callosciurus finlaysonii distribution.png | subdivision_ranks = Subspecies | subdivision_ref = <ref name="Thorington-finlaysonii">{{cite book|last1=Thorington|first1=R.W. Jr.|last2=Hoffmann|first2=R.S.|year=2005|chapter=Callosciurus finlaysonii|chapter-url=https://www.departments.bucknell.edu/biology/resources/msw3/browse.asp?id=12400484|editor1-last=Wilson|editor1-first=D.E.|editor2-last=Reeder|editor2-first=D.M|url=http://www.bucknell.edu/msw3|title=Mammal Species of the World: a taxonomic and geographic reference|edition=3rd|publisher=The Johns Hopkins University Press|isbn=0-8018-8221-4|oclc=26158608}}</ref> | subdivision = 16 subspecies: * ''C. f. finlaysonii'' * ''C. f. albivexilli'' * ''C. f. folletti'' * ''C. f. frandseni'' * ''C. f. germaini'' * ''C. f. harmandi'' * ''C. f. trotteri'' * ''C. f. annellatus'' * ''C. f. bocourti'' * ''C. f. boonsongi'' * ''C. f. cinnamomeus'' * ''C. f. ferrugineus'' * ''C. f. menamicus'' * ''C. f. nox'' * ''C. f. sinistralis'' * ''C. f. williamsoni'' }}
'''Finlayson's squirrel''' or the '''variable squirrel''' ('''''Callosciurus finlaysonii''''') is a species of rodent in the family Sciuridae. It is found in Cambodia, Laos, Myanmar, Thailand, and Vietnam. It has numerous subspecies that vary greatly in appearance and it occurs in a wide range of wooded habitats, including gardens and parks in cities like Bangkok.<ref name=Francis2008>Francis, C.M. (2008). A Guide to the Mammals of Southeast Asia. Pp. 144–145, 333–334. Princeton University Press. {{isbn|978-0-691-13551-9}}</ref><ref name=EcologyAsia>Ecology Asia: [https://www.ecologyasia.com/verts/mammals/variable-squirrel.htm Variable or Finlayson's Squirrel]. Retrieved 11 July 2018.</ref> It was named in honour of the Scottish naturalist and traveller George Finlayson.
==Taxonomy and appearance== The Finlayson's squirrel has a head-and-body length of about {{convert|21-22|cm|in|abbr=on}} and its tail is about {{convert|22-24|cm|in|abbr=on}} long.<ref name=Francis2008/>
There are currently 16 recognised subspecies.<ref name="Thorington-finlaysonii" /> Additional subspecies are sometimes recognised. For example, some authorities recognise ''C. f. floweri'',<ref name=Francis2008/><ref name=Boonkhaw2017/> while others consider it a synonym of ''C. f. bocourti'' (as done in the following colour description).<ref name="Thorington-finlaysonii"/> The subspecific name of ''C. f. boonsongi'' commemorates Thai zoologist and conservationist Boonsong Lekagul.<ref>Moore, J.C., Tate, G.H.H. (1965). A study of the diurnal squirrels, Sciurinae, of the Indian and Indo-Chinese subregions. Fieldiana Zoology 48:1–351.</ref>
The pelage colour in this species is extremely variable and the subspecies are often defined by this feature. For example, ''C. f. finlaysonii'' (nominate) is overall whitish, ''C. f. albivexilli'', ''C. f. boonsongi'', ''C. f. germaini'' and ''C. f. nox'' are overall blackish (first with white tail-tip, second occasionally with white underside, face and feet), ''C. f. annellatus'' is overall rufous with a light band at the base of the tail, ''C. f. bocourti'' is whitish below with highly variable colour of the upperparts (whitish, grey, blackish, olive-brownish or reddish), ''C. f. cinnamomeus'' is overall reddish with a dark mid-back, ''C. f. ferrugineus'' is reddish-brown, ''C. f. harmandi'' has brownish upperparts, orange-red underparts and light grey tail, ''C. f. menamicus'' is reddish or orangish, often has greyish legs and flanks, and sometimes a white belly, and ''C. f. sinistralis'' has grizzled upperparts, reddish underparts and reddish tail with a pale band at the base.<ref name=Francis2008/><ref name=Boonkhaw2017>Boonkhaw, Phadet, Prayoon, Umphornpimon, Kanchanasaka, Budsabong, Hayashi, Fumio, Tamura, Noriko (2017). Colour polymorphism and genetic relationships among twelve subspecies of Callosciurus finlaysonii in Thailand. ''Mammalian Biology – Zeitschrift für Säugetierkunde 85'', 6–13. {{doi|10.1016/j.mambio.2017.02.001}}</ref> Unnamed populations also remain (for example, a population in central Laos is shiny black with red tail and shoulder/chest region) and even within described subspecies there are often some individual variations.<ref name="iucn status 12 November 2021" /><ref name=Francis2008/><ref name=Timmins2008>{{cite journal| last1=Timmins | first1=R.J. | last2=Duckworth | first2=J.W. | year=2008 | title=Diurnal squirrels (Mammalia Rodentia Sciuridae) in Lao PDR distribution, status and conservation | journal=Tropical Zoology | volume=21 | issue=1 | pages=11–56 }}</ref>
As currently defined, Finlayson's squirrel may comprise more than one species.<ref name="iucn status 12 November 2021" /> ''C. f. ferrugineus'' has been treated as a separate species.<ref name="Thorington-finlaysonii" /> A genetic study of the 12 subspecies in Thailand, including 7 from the mainland and 5 from islands, found that they belonged in six clades, which often were separated by water (large rivers in the mainland and the sea for the islands). The study also revealed that the mitochondrial DNA of this species compared to the closely related Pallas's squirrel is not monophyletic.<ref name=Boonkhaw2017/> A subsequent study recommended that, to maintain monophyletic species, ''flavimanus'' and ''griseimanus'', which traditionally are recognized as being subspecies of Pallas's squirrel in southeastern Indochina (central and southern Vietnam, adjacent parts of Cambodia and southern Laos), should be considered part of Finlayson's squirrel. The study also found that ''flavimanus'', as traditionally defined, actually consists of at least two clearly separate lineages, both part of Finlayson's squirrel.<ref name=Balakirev2019>{{cite journal| last1=Balakirev | first1=A.E. | last2=Rozhnov | first2=V.V. | year=2008 | title=Taxonomic revision of beautiful squirrels (Callosciurus, Rodentia: Sciuridae) from the Callosciurus erythraeus/finlaysonii complex and their distribution in eastern Indochina | journal=Raffles Bulletin of Zoology | volume=67 | pages=459–489 | doi=10.26107/RBZ-2019-0037 }}</ref>
<gallery widths="200px" heights="155px"> File:Callosciurus finlaysonii 85959681.jpg|''C. f. bocourti'' mating pair in Nonthaburi, Thailand (colour difference is individual, not related to male/female) File:Callosciurus finlaysonii 177035226.jpg|''C. f. bocourti'' in Wang Nam Khiao, Thailand File:Callosciurus finlaysonii cinnamomeus 86117364.jpg|''C. f. cinnamomeus'' in Khao Soi Dao, Thailand File:Callosciurus finlaysonii 99592168.jpg|''C. f. germaini'' on Côn Đảo, Vietnam </gallery>
==Behavior== [[File:Finlayson's squirrel (Callosciurus finlaysonii).jpg|thumb|upright|''C. f. bocourti'' eating watermelon at Wat Pho, Bangkok, Thailand]]
Like other squirrels of its genus (the "beautiful squirrels", ''Callosciurus''), Finlayson's squirrel is normally a canopy-dweller, feeding mainly on fruit.<ref>Kitamura, S., Yumoto, T., Poonswad, P., Chuailua, P., Plongmai, K., Maruhashi, T., & Noma, N. (2002). Interactions between fleshy fruits and frugivores in a tropical seasonal forest in Thailand. ''Oecologia, 133'', 559–572.</ref> Field evidence suggests that it has the usual form of dichromatic mammalian color vision, which may enable it to discriminate ripe from unripe fruits.<ref>Tamura, N., Fujii, Y., Boonkeow, P., & Kanchanasaka, B. (2015). Colour vision and food selection of ''Callosciurus finlaysonii'' (Sciuridae) in tropical seasonal forests. ''Journal of Tropical Ecology, 31'', 449–457.</ref>
==As an invasive species== The subspecies ''C. f. bocourti'' (syn. ''C. f. floweri''<ref name="Thorington-finlaysonii"/>) has been introduced to Singapore and two regions in Italy, probably a result of the species' popularity in the pet trade.<ref>Bertolino, S., & Lurz, P. W. W. (2013). ''Callosciurus'' squirrels: worldwide introductions, ecological impacts and recommendations to prevent the establishment of new invasive populations. ''Mammal Review'', 43, 22–33. {{doi|10.1111/j.1365-2907.2011.00204.x}}</ref> It is possible that some of the ''Callosciurus'' squirrels introduced into Japan are also Finlayson's squirrels.<ref>Kuramoto, T., Torii, H., Ikeda, H., Endo, H., Rerkamnuaychoke, W., & Oshida, T. (2012). Mitochondria DNA sequences of Finlayson's squirrel found in Hamamatsu, Shizuoka Prefecture, Japan. ''Mammal Study, 37'', 63–67</ref>
Finlayson's squirrel has also been introduced in the Philippines, particularly in the Greater Manila Area where it is considered an invasive species.<ref>{{Cite web|url=https://businessmirror.com.ph/2021/05/31/invasive-squirrel-species-seen-as-threat-to-wildlife-and-farms/|title = Invasive squirrel species seen as threat to wildlife and farms | Jonathan L. Mayuga| website=BusinessMirror |date = 31 May 2021}}</ref> As of April 2026, sightings of the species have been recorded in Metro Manila, Cavite, Batangas, Rizal and Nueva Ecija according to the Department of Environment and Natural Resources–Biodiversity Management Bureau (DENR-BMB); within Metro Manila, the Finlayson's squirrel has been spotted in some forested areas of Makati, Muntinlupa and Quezon City.<ref>{{Cite news |last=Ferreras |first=Vince Angelo |date=20 April 2026 |title=What to do after spotting a Finlayson’s squirrel? |url=https://www.gmanetwork.com/news/topstories/nation/984662/environmental-impact-health-risks-squirrel-invasion/story/ |access-date=21 April 2026 |publisher=GMA News Online}}</ref><ref>{{Cite news |last=Bosano |first=Rafael |date=21 April 2026 |title=Publiko binalaan sa posibleng panganib sa kalusugan, kalikasan ng Finlayson’s Squirrel |url=https://www.youtube.com/watch?v=eQzDemzuqVY |access-date=21 April 2026 |publisher=ABS-CBN News |language=tl |via=YouTube |quote=Sa Metro Manila, nakikita na ang mga squirrel sa ilang mapupunong bahagi ng Makati, Quezon City at Muntinlupa City. |trans-quote=In Metro Manila, the [Finlayson's] squirrel can already be found in certain forested areas of Makati, Quezon City and Muntinlupa City.}}</ref>
In the European Union, due to the significant negative impacts of its introduction to the ecosystem, it is included in the list of invasive alien species of Union concern and hence cannot be imported, bred, transported, commercialized, or intentionally released into the environment in any of its member states.<ref>{{Cite web |title=List of Invasive Alien Species of Union concern |url=https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:02016R1141-20250807 |date=7 August 2025 |access-date=30 March 2026|website=eur-lex.europa.eu}}</ref><ref>{{Cite web |title=Regulation No. 1143/2014 of the European parliament and of the council of 22 October 2014 on the prevention and management of the introduction and spread of invasive alien species |url=https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32014R1143&from=EN |publisher=European Union |date=4 November 2014 |location=Strasbourg |access-date=30 March 2026 |archive-date=3 March 2017 |archive-url=https://web.archive.org/web/20170303185733/http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32014R1143&from=EN |url-status=live }}</ref>
==References== {{Reflist}}
==External links== *[https://web.archive.org/web/20110716084253/http://www.wildsingapore.per.sg/discovery/factsheet/squirrelvariable.htm Wildlife Singapore Photos and description] *[http://siamensis.org/content/2339 Photo gallery showing some of the variations of Finlayson's Squirrel.]
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Category:Callosciurus Category:Mammals of Southeast Asia Category:Rodents of Myanmar Category:Rodents of Thailand Category:Rodents of Laos Category:Fauna of Italy Category:Mammals described in 1823 Category:Taxa named by Thomas Horsfield Category:Taxonomy articles created by Polbot