''Tupaia'' is a

treeshrew The treeshrews (also called tree shrews or banxrings) are small mammals native to the tropical forests of South and Southeast Asia. They make up the entire order Scandentia (from Latin ''scandere'', "to climb"), which split into two families: the ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

in the family

Tupaiidae Tupaiidae is one of two families of treeshrews, the other family being Ptilocercidae. The family contains three living genera and 19 living species. The family name derives from ''tupai'', the Malay word for treeshrew and also for squirrel which ...

that was first described by

Thomas Stamford Raffles Sir Thomas Stamford Bingley Raffles (5 July 1781 – 5 July 1826) was a British Colonial Office, colonial official who served as the List of governors of the Dutch East Indies, governor of the Dutch East Indies between 1811 and 1816 and lieut ...

in 1821.

Taxonomy

Raffles provided the name of this genus, which derives from the Malay word meaning a

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

or a small animal resembling one.

Characteristics

Raffles described the genus as having an elongated snout, eight to 10 incisors, well-developed limbs, five-toed naked feet, and the sole furnished with projecting pads and sharp claws, with a habit and tail of a squirrel.

Marcus Ward Lyon Marcus Ward Lyon Jr. (February 5, 1875 – May 19, 1942) was an American mammalogist, bacteriologist, and pathologist. He was born into a military family, and demonstrated an early interest in zoology by collecting local wildlife around his f ...

published a revision of the genus in 1913, and also noted the squirrel-like appearance of ''Tupaia'' species, which only lack the long black whiskers and have smaller ears. They do not have any markings on the face, the naked area of the nose is finely reticulated, an oblique stripe on the shoulder is more or less distinct, and the tail is haired but not tufted. The

braincase In human anatomy, the neurocranium, also known as the braincase, brainpan, brain-pan, or brainbox, is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calv ...

is about as wide as the

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

ry tooth row is long. The

temporal fossa The temporal fossa is a fossa (shallow depression) on the side of the skull bounded by the temporal lines above, and the zygomatic arch below. Its floor is formed by the outer surfaces of four bones of the skull. The fossa is filled by the te ...

is smaller than the

orbit In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an ...

. The

dental formula Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology ...

is . The first pair of upper

incisors Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...

is longer than the second, while the second pair of lower incisors is slightly larger than the first and third pairs. The lower canines are better developed than the upper ones and stand high above the adjacent

premolars The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mout ...

. The size of head, body, and tail varies between species. One outstanding characteristic of ''Tupaia'' species is their color vision. They have rod and

cone In geometry, a cone is a three-dimensional figure that tapers smoothly from a flat base (typically a circle) to a point not contained in the base, called the '' apex'' or '' vertex''. A cone is formed by a set of line segments, half-lines ...

visual receptors similar to humans and other primates.

Classification and taxonomic history

When Diard and Duvaucel described the first specimen of the

common treeshrew The common treeshrew (''Tupaia glis'') is a small mammal in the treeshrew family Tupaiidae, and is native to Thailand, Malaysia, Singapore and Indonesia. It has been listed as Least Concern by IUCN as it remains common and displays some adaptabil ...

''Tupaia glis'' in 1820, they considered it a species of ''

Sorex The genus ''Sorex'' includes many of the common shrews of Eurasia and North America, and contains at least 142 known species and subspecies. Members of this genus, known as long-tailed shrews, are the only members of the tribe Soricini of the s ...

.''Diard, P.M., Duvaucel, A. (1820)
"Sur une nouvelle espèce de Sorex — Sorex Glis"
Asiatick researches, or, Transactions of the society instituted in Bengal, for inquiring into the history and antiquities, the arts, sciences, and literature of Asia, Volume 14: 470–475. '' T. everetti'' was moved back into the genus from ''

Urogale The Mindanao treeshrew (''Tupaia everetti''), also called the Philippine tree shrew, is a species of treeshrew endemic to the Mindanao region in the Philippines. It was formerly considered the only member of the genus ''Urogale'', but that genus ...

'', disbanding the latter, based on a 2011 molecular phylogeny. The following species are in the genus ''Tupaia'': *

Northern treeshrew The northern treeshrew (''Tupaia belangeri'') is a treeshrew species native to Southeast Asia. In 1841, the German zoologist Johann Andreas Wagner first used the specific name ''Cladobates belangeri'' for treeshrews that had been collected in Pe ...

''T. belangeri'' — (

Wagner Wilhelm Richard Wagner ( ; ; 22 May 181313 February 1883) was a German composer, theatre director, essayist, and conductor who is chiefly known for his operas (or, as some of his mature works were later known, "music dramas"). Unlike most o ...

, 1841) *

Golden-bellied treeshrew The golden-bellied treeshrew (''Tupaia chrysogaster'') is a treeshrew species within the Tupaiidae. It is also called Mentawai treeshrew as it is endemic to the Indonesian Mentawai islands of Sipora, North and South Pagai. It lives in forests, a ...

''T. chrysogaster'' — G. S. Miller, 1903 *

Bangka Island treeshrew The Bangka Island treeshrew (''Tupaia discolor''), also known as the Bangkan treeshrew, is a treeshrew species within the Tupaiidae. It was previously listed as a junior synonym to '' Tupaia glis'', but was raised up to species status in 2013. It ...

''T. dicolor'' —

Lyon Lyon (Franco-Provençal: ''Liyon'') is a city in France. It is located at the confluence of the rivers Rhône and Saône, to the northwest of the French Alps, southeast of Paris, north of Marseille, southwest of Geneva, Switzerland, north ...

, 1906 * Striped treeshrew ''T. dorsalis'' —

Schlegel Schlegel is a German occupational surname. Notable people with the surname include: * Anthony Schlegel (born 1981), American football player * August Wilhelm Schlegel (1767–1845), German poet, brother of Friedrich * Brad Schlegel (born 1968), C ...

, 1857 *

Mindanao treeshrew The Mindanao treeshrew (''Tupaia everetti''), also called the Philippine tree shrew, is a species of treeshrew endemic to the Mindanao region in the Philippines. It was formerly considered the only member of the genus ''Urogale'', but that genus ...

''T. everetti'' —

Thomas Thomas may refer to: People * List of people with given name Thomas * Thomas (name) * Thomas (surname) * Saint Thomas (disambiguation) * Thomas Aquinas (1225–1274) Italian Dominican friar, philosopher, and Doctor of the Church * Thomas the A ...

, 1892 * Sumatran treeshrew ''T. ferruginea'' — Raffles 1821 *

Common treeshrew The common treeshrew (''Tupaia glis'') is a small mammal in the treeshrew family Tupaiidae, and is native to Thailand, Malaysia, Singapore and Indonesia. It has been listed as Least Concern by IUCN as it remains common and displays some adaptabil ...

''T. glis'' — Diard & Duvaucel, 1820 *

Slender treeshrew The slender treeshrew (''Tupaia gracilis'') is a treeshrew species within the Tupaiidae. It is native to Borneo Borneo () is the List of islands by area, third-largest island in the world, with an area of , and population of 23,053,723 (202 ...

''T. gracilis'' —

, 1893 * Javan treeshrew ''T. hypochrysa'' —

, 1895 * Horsfield's treeshrew ''T. javanica'' — Horsfield, 1821Lyon, M. W., Jr. (1913)
''Tree shrews: An account of the mammalian family Tupaiidae''
Proceedings of the United States National Museum, 45:1–188. *

Long-footed treeshrew The long-footed treeshrew (''Tupaia longipes'') is a treeshrew species within the Tupaiidae. It is endemic to Borneo and threatened due to deforestation Deforestation or forest clearance is the removal and destruction of a forest or s ...

''T. longipes'' —

, 1893 *

Pygmy treeshrew The pygmy treeshrew (''Tupaia minor'') is a treeshrew species within the family Tupaiidae. It is native to Thailand, Malaysia and Indonesia. The generic name is derived from the malay language, Malay word ''tupai'' meaning squirrel or small anim ...

''T. minor'' — Günther, 1876 *

Mountain treeshrew The mountain treeshrew (''Tupaia montana'') is a treeshrew species within the Tupaiidae. It is endemic to Borneo and inhabits montane forests in Sarawak and Sabah, Malaysia, and Kalimantan, Indonesia. The first specimen was described by Oldfield ...

''T. montana'' —

, 1892 * Nicobar treeshrew ''T. nicobarica'' — ( Zelebor, 1868) *

Palawan treeshrew The Palawan treeshrew (''Tupaia palawanensis'') is a treeshrew species endemic to the Palawan Island, Philippines, where it occurs from sea level to an elevation of . The population is considered steady. Formerly, it was considered a subspecies o ...

''T. palawanensis'' —

, 1894 *

Painted treeshrew The painted treeshrew (''Tupaia picta'') is a treeshrew species of the family Tupaiidae. The first specimen was described by Oldfield Thomas and was part of a zoological collection from northern Borneo obtained by the British Museum of Natural H ...

''T. picta'' —

, 1892 * Kalimantan treeshrew ''T. salatana'' —

, 1895 *

Ruddy treeshrew The ruddy treeshrew (''Tupaia splendidula'') is a treeshrew species in the family Tupaiidae. It is endemic to Borneo, the Natuna Islands and the Anambas Islands. Habitat and threats The ruddy treeshrew occurs in the forests of Indonesia. It l ...

''T. splendidula'' —

J. E. Gray John Edward Gray (12 February 1800 – 7 March 1875) was a British zoologist. He was the elder brother of zoologist George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray (1766–1828). The same is used for a zoo ...

, 1865 * Large treeshrew ''T. tana'' — Raffles, 1821 * †'' Tupaia miocenica'' — Mein & Ginsburg, 1997 In the past, various authors proposed to place treeshrews in the ordinal rank

Insectivora The Order (biology), order Insectivora (from Latin ''insectum'' "insect" and ''vorare'' "to eat") is a now-abandoned biological grouping within the class of mammals. Some species have now been moved out, leaving the remaining ones in the order ...

, or considered them close relatives of

primates Primates is an order of mammals, which is further divided into the strepsirrhines, which include lemurs, galagos, and lorisids; and the haplorhines, which include tarsiers and simians ( monkeys and apes). Primates arose 74–63 ...

. Since 1972, the treeshrew families

and Ptilocercidae are grouped in the order Scandentia.Martin, R. D. (1968). ''Reproduction and Ontogeny in tree-shrews (''Tupaia belangeri''), with reference to their general behaviour and taxonomic relationships''. Zeitschrift für Tierpsychologie 25(4): 409–495.

Distribution and habitat

''Tupaia'' species range from

northeastern India Northeast India, officially the North Eastern Region (NER), is the easternmost region of India representing both a geographic and political administrative division of the country. It comprises eight states—Arunachal Pradesh, Assam, Manipur, M ...

Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ...

Nicobar Islands The Nicobar Islands are an archipelago, archipelagic island chain in the eastern Indian Ocean. They are located in Southeast Asia, northwest of Aceh on Sumatra, and separated from Thailand to the east by the Andaman Sea. Located southeast of t ...

eastward to some of the

Philippine Islands The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

, and from

central China Central China () is a List of regions of China, region in China. It mainly includes the provinces of China, provinces of Henan, Hubei and Hunan. Jiangxi is sometimes also regarded to be part of this region. Central China is now officially par ...

south to

Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...

Borneo Borneo () is the List of islands by area, third-largest island in the world, with an area of , and population of 23,053,723 (2020 national censuses). Situated at the geographic centre of Maritime Southeast Asia, it is one of the Greater Sunda ...

and

Sumatra Sumatra () is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the list of islands by area, sixth-largest island in the world at 482,286.55 km2 (182,812 mi. ...

, including islands on the southwest coast. They do not occur on

Celebes Sulawesi ( ), also known as Celebes ( ), is an island in Indonesia. One of the four Greater Sunda Islands, and the world's 11th-largest island, it is situated east of Borneo, west of the Maluku Islands, and south of Mindanao and the Sulu Archi ...

, nor on islands to the east of Java, with the possible exception of

Bali Bali (English:; Balinese language, Balinese: ) is a Provinces of Indonesia, province of Indonesia and the westernmost of the Lesser Sunda Islands. East of Java and west of Lombok, the province includes the island of Bali and a few smaller o ...

. They inhabit the dense undergrowth of tropical forests. With the exception of ''T. minor'', they are primarily terrestrial and forage on the forest floor, usually below . Since they are rarely seen crossing wide roads, populations likely are negatively affected by fragmentation of forests caused by

logging Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidder, skidding, on-site processing, and loading of trees or trunk (botany), logs onto logging truck, truckssensitivity is highly developed as the broad frequency range of their

hearing Hearing, or auditory perception, is the ability to perceive sounds through an organ, such as an ear, by detecting vibrations as periodic changes in the pressure of a surrounding medium. The academic field concerned with hearing is auditory sci ...

reaches far into the

ultrasonic Ultrasound is sound with frequencies greater than 20 kilohertz. This frequency is the approximate upper audible limit of human hearing in healthy young adults. The physical principles of acoustic waves apply to any frequency range, includi ...

. The shape of the cheek-teeth of ''Tupaia'' species indicate they are foremost

insectivore file:Common brown robberfly with prey.jpg, A Asilidae, robber fly eating a hoverfly An insectivore is a carnivore, carnivorous animal or plant which eats insects. An alternative term is entomophage, which can also refer to the Entomophagy ...

s. Captive specimens were reported to hunt

ants Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of ...

, flies,

crickets Crickets are orthopteran insects which are related to bush crickets and more distantly, to grasshoppers. In older literature, such as Imms,Imms AD, rev. Richards OW & Davies RG (1970) ''A General Textbook of Entomology'' 9th Ed. Methuen 886 ...

grasshopper Grasshoppers are a group of insects belonging to the suborder Caelifera. They are amongst what are possibly the most ancient living groups of chewing herbivorous insects, dating back to the early Triassic around 250 million years ago. Grassh ...

cockroach Cockroaches (or roaches) are insects belonging to the Order (biology), order Blattodea (Blattaria). About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known Pest (organism), pests. Modern cockro ...

es, and small beetles. They hold their food between their forelegs while sitting on their haunches. After feeding, they smooth their heads and faces with both forepaws, and lick their lips and palms. They are also fond of water, both to drink and to bathe. They fortify their diet with soft fruits that are mostly dispersed by birds. They swallow the pulp, but reject fibrous components, which they cannot digest due to their long and small

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. T ...

s and rudimentary ceca. The well-developed

olfactory perception The sense of smell, or olfaction, is the special sense through which smells (or odors) are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste. In humans, it ...

of treeshrews enables them to easily detect food among the leaf litter on the forest floor. Their sensitivity for odours coupled with

scent-marking In ethology, territory is the sociographical area that an animal consistently defends against conspecificity, conspecific competition (biology), competition (or, occasionally, against animals of other species) using agonistic behaviors or (less ...

of their

territories A territory is an area of land, sea, or space, belonging or connected to a particular country, person, or animal. In international politics, a territory is usually a geographic area which has not been granted the powers of self-government, ...

is important in their interaction with

conspecifics Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species. Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organism ...

.Kawamichi, T. and Kawamichi, M. (1979). ''Spatial Organization and Territory of Tree Shrews'' (Tupaia glis). Animal Behavior 27(2): 381–393. Observations of ''Tupaia'' species in their natural habitats suggest they usually form monogamous pairs. Social behaviour differs between species and the available food resources in their territories. Where food is adequate and sufficient, they tolerate conspecifics without engaging in territorial disputes. Common treeshrews observed in the

Bukit Timah Nature Reserve The Bukit Timah Nature Reserve (abbreviation: BTNR) is a nature reserve near the geographic centre of Singapore, located on the slopes of Bukit Timah Hill, the country's highest natural peak standing at a height of approximately , and parts of ...

defended diminishing food resources by chasing away residents of adjacent areas. Birds of prey, snakes, and small carnivores are known to hunt treeshrews. Humans have no interest in killing them for food because of their unpleasant taste, and they are rarely seen as pests.Cisneros, L. (2005). "Tupaia glis" (On-line), Animal Diversity Web.

Reproduction and development

Treeshrews share more similarity with rodents and squirrels than with primates in regards to their reproduction and development. In contrast to primates, which produce one baby with longer gestation periods, treeshrews generally have litters of two or three young and are only ''in utero'' about 45 days. Female treeshrews give birth in nests made of many dry leaves, and are known to leave the young unattended while returning occasionally to give them milk. Parental care of ''Tupaia'' is relatively limited. The young remain in the nest for 33 days on average, developing gradually before they exit the nest. Ten identified embryonic developmental stages are seen in ''Tupaia'' species. Baby treeshrews are sexually immature until about 90 days after birth.

Medical research

Their close relationship to primates makes treeshrews important model organisms in human medical research. A study investigating the effects of the

Borna disease virus The Borna disease viruses 1 and 2 (BoDV-1 and BoDV-2) are members of the species ''Mammalian 1 orthobornavirus'' and cause Borna disease in mammals. Virology Genome BoDV-1/2 have the smallest genome (8.9 kilobases) of any ''Mononegavir ...

on treeshrews has given new insight into neurological disease. Since ''Tupaia'' species share so many similarities with primates, yet are more abundant and have more plentiful progeny than them, interest is increasing in using them as an alternative model for use in human medical research. Successful psychosocial studies were carried out, and dramatic behavioral, neuroendocrinal, and physiological changes occurred in subordinate males of ''Tupaia'', similar to depressed human patients. Their susceptibility to

virus A virus is a submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are ...

es has also piqued interest in using them to study immune responses to infections such as hepatitis'' ''B. ''Tupaia'' species have been used to overcome the limitations of using rodent models in the study of human biology and disease mechanisms, as well as the development of new drugs and diagnostic tools. Recent studies have used treeshrews to study infectious, metabolic, neurological, and psychiatric diseases, as well as cancers. In 2013, the ''

Virology Journal ''Virology Journal'' is an Open access (publishing), open-access Peer review, peer-reviewed medical journal published by BioMed Central. It publishes research related to viruses and the prevention of infection, viral infection (including vaccine ...

'' published an article that documents the use of the

northern treeshrew The northern treeshrew (''Tupaia belangeri'') is a treeshrew species native to Southeast Asia. In 1841, the German zoologist Johann Andreas Wagner first used the specific name ''Cladobates belangeri'' for treeshrews that had been collected in Pe ...

(''T. belangeri'') as medical models for the H1N1 influenza virus. This was advantageous because other possible candidates such as guinea pigs, rats, mice, and other rodents leave gaps in the information, especially regarding clinical symptoms and transmission. ''Tupaia'', though, displays moderate systemic and respiratory symptoms, as well as pathological changes in the respiratory tract, supporting its use as a beneficial model in H1N1 research.Yang, Z. F., Zhao, J., Zhu, Y. T., Wang, Y. T., Liu, R., Zhao, S. S., Li, R. F., Yang, C., Li, J., Zhong, N. S. (2013). ''The tree shrew provides a useful alternative model for the study of influenza H1N1 virus''. Virology Journal 10 (1): 111.

References

{{Authority control Treeshrews Mammal genera Taxa named by Thomas Stamford Raffles