Finlayson's squirrel or the variable squirrel (''Callosciurus finlaysonii'', sometimes misspelled ''C. finlaysoni'') is a species of

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...

in the family

Sciuridae Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrels. Squ ...

. It is found in

Cambodia Cambodia (; also Kampuchea ; km, កម្ពុជា, UNGEGN: ), officially the Kingdom of Cambodia, is a country located in the southern portion of the Indochinese Peninsula in Southeast Asia, spanning an area of , bordered by Thailand t ...

Laos Laos (, ''Lāo'' )), officially the Lao People's Democratic Republic ( Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ, French: République démocratique populaire lao), is a socialist ...

Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John C. Wells, Joh ...

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is bo ...

, and

Vietnam Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making i ...

. The species occurs in a wide range of wooded habitats, including gardens and parks in cities like

Bangkok Bangkok, officially known in Thai language, Thai as Krung Thep Maha Nakhon and colloquially as Krung Thep, is the capital and most populous city of Thailand. The city occupies in the Chao Phraya River delta in central Thailand and has an estima ...

.Francis, C.M. (2008). A Guide to the Mammals of Southeast Asia. Pp. 144–145, 333–334. Princeton University Press. Ecology Asia
Variable or Finlayson's Squirrel
Retrieved 11 July 2018. It was named in honour of the Scottish naturalist and traveller

George Finlayson George Finlayson (1790–1823) was a Scots people, Scottish Natural history, naturalist and traveller. He was called one of the best naturalists of his day, and he was noted for his pioneering studies of the plants, animals, and people of southern ...

. It has numerous

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

that vary greatly in appearance. One of these, ''C. f. bocourti'' (

syn. The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linnae ...

''C. f. floweri''), has been introduced to

Singapore Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, borde ...

and two regions in

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

, probably a result of the species' popularity in the pet trade. It is possible that some of the ''

Callosciurus ''Callosciurus'' is a genus of squirrels collectively referred to as the "''beautiful squirrels''". They are found mainly in Southeast Asia, though a few species also occur in Nepal, northeastern India, Bangladesh and southern China. Several of t ...

'' squirrels introduced into Japan are also Finlayson's squirrels. Finlayson’s squirrel has also been introduced in the Philippines, particularly in the

Greater Manila The Greater Manila Area is the contiguous urbanization region surrounding the Metropolitan Manila area. This built-up zone includes Metro Manila and the neighboring provinces of Bulacan to the north, Cavite and Laguna to the south, and Rizal ...

area where it is considered as an

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

Taxonomy and appearance

The Finlayson's squirrel has a head-and-body length of about and its tail is about long. There are currently 16 recognised subspecies. Additional subspecies are sometimes recognised. For example, some authorities recognise ''C. f. floweri'', while others consider it a

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

of ''C. f. bocourti'' (as done in the following colour description). The subspecific name of ''C. f. boonsongi'' commemorates Thai zoologist and conservationist

Boonsong Lekagul Boonsong Lekagul (15 December 1907 – 9 February 1992) was a Thai medical doctor, biologist, ornithologist, herpetologist,Boelens, Bo; Watkins, Michael; Grayson, Michael. (2011). ''The Eponym Dictionary of Reptiles''. Baltimore: Johns Hopkins Uni ...

. The pelage colour in this species is extremely variable and the subspecies are often defined by this feature. For example, ''C. f. finlaysonii'' (

nominate Nomination is part of the process of selecting a candidate for either election to a public office, or the bestowing of an honor or award. A collection of nominees narrowed from the full list of candidates is a short list. Political office In the ...

) 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 Rufous () is a color that may be described as reddish-brown or brownish-red, as of rust or oxidised iron. The first recorded use of ''rufous'' as a color name in English was in 1782. However, the color is also recorded earlier in 1527 as a dia ...

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 The olive, botanical name ''Olea europaea'', meaning 'European olive' in Latin, is a species of small tree or shrub in the family Oleaceae, found traditionally in the Mediterranean Basin. When in shrub form, it is known as ''Olea europaea'' ...

-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.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 Saugetierkunde 85'', 6–13. 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. As currently defined, Finlayson's squirrel may comprise more than one species. ''C. f. ferrugineus'' has been treated as a separate species. A genetic study of the 12 subspecies in Thailand, including 7 from the mainland and 5 from islands, found that they belonged in six

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

s, 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 Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial D ...

of this species compared to the closely related

Pallas's squirrel Pallas's squirrel (''Callosciurus erythraeus''), also known as the red-bellied tree squirrel, is a species of squirrel native to Greater China, India, and Southeast Asia. Description Pallas's squirrel is a medium-sized tree squirrel, with ...

is not

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

Behavior

Like other squirrels of its genus (the "beautiful squirrels", ''

''), Finlayson's squirrel is normally a canopy-dweller, feeding mainly on fruit. Field evidence suggests that it has the usual form of dichromatic mammalian color vision, which may enable it to discriminate ripe from unripe fruits.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.

References

External links

Wildlife Singapore Photos and description

Photo gallery showing some of the variations of Finlayson's Squirrel.
{{Taxonbar, from=Q2086835 Callosciurus Mammals of Southeast Asia Rodents of Myanmar Rodents of Thailand Rodents of Laos Fauna of Italy Mammals described in 1823 Taxa named by Thomas Horsfield Taxonomy articles created by Polbot