The treeshrews (also called tree shrews or banxrings) are small

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s native to the

tropical forest Tropical forests are forested ecoregions with tropical climates – that is, land areas approximately bounded by the Tropic of Cancer, tropics of Cancer and Tropic of Capricorn, Capricorn, but possibly affected by other factors such as prevailing ...

s of South and

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

. They make up the entire

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Scandentia (from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''scandere'', "to climb"), which split into two

families Family (from ) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictability, structure, and safety as ...

: the

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 ...

(19 species, "ordinary" treeshrews), and the Ptilocercidae (one species, the

pen-tailed treeshrew The pen-tailed treeshrew (''Ptilocercus lowii'') is a treeshrew of the family Ptilocercidae native to southern Thailand, the Malay Peninsula, Borneo, and some Indonesian islands. It is the only living species in the genus ''Ptilocercus''. All ...

). Though called 'treeshrews', and despite having previously been classified in

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 ...

, they are not true

shrew Shrews ( family Soricidae) are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to dif ...

s, and not all species live in trees. They are

omnivore An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize t ...

s; among other things, treeshrews eat fruit. As fellow members of

Euarchonta The Euarchonta are a proposed grandorder of mammals: the order Scandentia (treeshrews), and its sister Primatomorpha mirorder, containing the Dermoptera (colugos) and the primates (Plesiadapiformes and descendants). The term "Euarchonta" (mea ...

, treeshrews are closely related to

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 ...

, and have been used as an alternative to primates in experimental studies of

myopia Myopia, also known as near-sightedness and short-sightedness, is an eye condition where light from distant objects focuses in front of, instead of on, the retina. As a result, distant objects appear blurry, while close objects appear normal. ...

, psychosocial stress, and

hepatitis Hepatitis is inflammation of the liver parenchyma, liver tissue. Some people or animals with hepatitis have no symptoms, whereas others develop yellow discoloration of the skin and whites of the eyes (jaundice), Anorexia (symptom), poor appetite ...

Description

Treeshrews are slender animals with long tails and soft, greyish to reddish-brown fur. The terrestrial species tend to be larger than the arboreal forms, and to have larger claws, which they use for digging up insect prey. They have poorly developed canine teeth and unspecialised molars, with an overall

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 ...

of They have a higher

brain to body mass ratio The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for special senses ...

than any other mammal, including

human Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...

s, but high ratios are not uncommon for animals weighing less than . Treeshrews have good

vision Vision, Visions, or The Vision may refer to: Perception Optical perception * Visual perception, the sense of sight * Visual system, the physical mechanism of eyesight * Computer vision, a field dealing with how computers can be made to gain und ...

, which is binocular in the case of the more arboreal species.

Reproduction

Female treeshrews have a gestation period of 45–50 days and give birth to up to three young in nests lined with dry leaves inside tree hollows. The young are born blind and hairless, but are able to leave the nest after about a month. During this period, the mother provides relatively little maternal care, visiting her young only for a few minutes every other day to suckle them. Treeshrews reach sexual maturity after around four months, and breed for much of the year, with no clear breeding season in most species.

Behavior

Treeshrews live in small family groups, which defend their

territory 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, ...

from intruders. Most are diurnal, although the

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

. They mark their territories using various

scent gland Scent gland are exocrine glands found in most mammals. They produce semi-viscous secretions which contain pheromones and other semiochemical compounds. These odor-messengers indicate information such as status, territorial marking, mood, and se ...

s or

urine Urine is a liquid by-product of metabolism in humans and many other animals. In placental mammals, urine flows from the Kidney (vertebrates), kidneys through the ureters to the urinary bladder and exits the urethra through the penile meatus (mal ...

, depending on the particular species.

Diet

Treeshrews are

omnivorous An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize ...

, feeding on insects, small vertebrates, fruit, and seeds. Among other things, treeshrews eat ''

Rafflesia ''Rafflesia'' (), or stinking corpse lily, is a genus of Parasitic plants, parasitic flowering plants in the family Rafflesiaceae. The species have enormous flowers, the buds rising from the ground or directly from the lower stems of their host p ...

'' fruit. The pen-tailed treeshrew in Malaysia is able to consume large amounts of naturally fermented nectar from flower buds of the bertam palm '' Eugeissona tristis'' (with up to 3.8% alcohol content) the entire year without it having any effects on behaviour. Treeshrews have also been observed intentionally eating foods high in

capsaicin Capsaicin (8-methyl-''N''-vanillyl-6-nonenamide) (, rarely ) is an active component of chili peppers, which are plants belonging to the genus ''Capsicum''. It is a potent Irritation, irritant for Mammal, mammals, including humans, and produces ...

, a behavior unique among mammals other than humans. A single

TRPV1 The transient receptor potential cation channel subfamily V member 1 (TRPV1), also known as the capsaicin receptor and the vanilloid receptor 1, is a protein that, in humans, is encoded by the ''TRPV1'' gene. It was the first isolated member of ...

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, ...

reduces their pain response to capsaicinoids, which scientists believe is an

evolutionary adaptation In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the p ...

to be able to consume spicy foods in their natural habitats. Pitcher plants like the ''

Nepenthes lowii ''Nepenthes lowii'' (), commonly called Low's pitcher plant,Phillipps, A. & A. Lamb 1996. ''Pitcher-Plants of Borneo''. Natural History Publications (Borneo), Kota Kinabalu. is a tropical pitcher plant endemic to Borneo. It is named after Hugh L ...

'', supplements its carnivorous diet with tree shrew droppings. Murud N

Taxonomy

Treeshrews were moved from the order

into the order

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 ...

because of certain internal similarities to primates (for example, similarities in the

brain The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for ...

anatomy Anatomy () is the branch of morphology concerned with the study of the internal structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old scien ...

, highlighted by Sir Wilfrid Le Gros Clark), and classified as a "primitive

prosimian Prosimians are a group of primates that includes all living and extinct Strepsirrhini, strepsirrhines (lemurs, Lorisoidea, lorisoids, and Adapiformes, adapiforms), as well as the Haplorhini, haplorhine tarsiers and their extinct relatives, the Om ...

", however they were soon split from the primates and moved into their own

. Taxonomists continue to refine the treeshrews' relations to primates and to other closely related clades.

Molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

studies have suggested that the treeshrews, with the primates and the flying lemurs (colugos), belong to the

grandorder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized ...

. According to this classification, the Euarchonta are sister to the

Glires Glires (, Latin ''glīrēs'' 'dormice') is a clade (sometimes ranked as a grandorder) consisting of rodents and lagomorphs ( rabbits, hares, and pikas). The hypothesis that these form a monophyletic group has been long debated based on morph ...

(

lagomorphs The lagomorphs () are the members of the taxonomic order Lagomorpha, of which there are two living families: the Leporidae (rabbits and hares) and the Ochotonidae (pikas). There are 110 recent species of lagomorph, of which 109 species in twelve ...

and

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

s), and the two groups are combined into the

superorder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized ...

Euarchontoglires Euarchontoglires (from: '' Euarchonta'' ("true rulers") + '' Glires'' ("dormice")), synonymous with Supraprimates, is a clade and a superorder of placental mammals, the living members of which belong to one of the five following groups: rodents ...

. However, the alternative placement of treeshrews as sister to both Glires and

Primatomorpha Primatomorpha is a proposed mirorder of mammals containing the orders Dermoptera (or colugos) and Primates. Primatomorpha is sister to Scandentia, together forming the Euarchonta. The term "Primatomorpha" first appeared in the general scien ...

cannot be ruled out. Some studies place Scandentia as sister of the Glires, which would invalidate Euarchonta: It is this organization that is shown in the tree diagram below. Several other arrangements of these orders have been proposed in the past, and the above tree is only a well-favored proposal. Although it is known that Scandentia is one of the most basal euarchontoglire clades, the exact phylogenetic position is not yet considered resolved: It may be a sister of Glires, Primatomorpha, or

Dermoptera Colugos (), flying lemurs, or cobegos (), are arboreal gliding euarchontogliran mammals that are native to Southeast Asia. Their closest evolutionary relatives are primates. There are just two living species of colugos: the Sunda flying lemur ...

, or separate from and sister to all other Euarchontoglires. Shared

short interspersed nuclear elements Short interspersed nuclear elements (SINEs) are non-autonomous, non-coding transposable elements (TEs) that are about 100 to 700 base pairs in length. They are a class of retrotransposons, DNA elements that amplify themselves throughout eukaryo ...

(SINEs) offer strong evidence for Scandentia belonging to the Euarchonta group:

Order Scandentia

The 23

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

are placed in four

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

, which are divided into two families. The majority are in the "ordinary" treeshrew family,

, but one species, the

, is different enough to warrant placement in its own family, Ptilocercidae; the two families are thought to have separated 60 million years ago. The former Tupaiidae genus '' Urogale'' was disbanded in 2011 when the Mindanao treeshrew was moved to ''Tupaia'' based on a molecular phylogeny. ;Family

: *Genus '' Anathana'' ** Madras treeshrew, ''A. ellioti'' *Genus '' Dendrogale'' ** Bornean smooth-tailed treeshrew, ''D. melanura'' ** Northern smooth-tailed treeshrew, ''D. murina'' *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'' ** Golden-bellied treeshrew, ''T. chrysogaster'' ** Bangka Island treeshrew, ''T. discolor'' ** Striped treeshrew, ''T. dorsalis'' ** Mindanao treeshrew, ''T. everetti'' ** Sumatran treeshrew, ''T. ferruginea'' **

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'' ** Slender treeshrew, ''T. gracilis'' ** Javan treeshrew, ''T. hypochrysa'' ** Horsfield's treeshrew, ''T. javanica'' ** Long-footed treeshrew, ''T. longipes'' **

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'' **

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'' ** Nicobar treeshrew, ''T. nicobarica'' ** Palawan treeshrew, ''T. palawanensis'' ** Painted treeshrew, ''T. picta'' ** Kalimantan treeshrew, ''T. salatana'' ** Ruddy treeshrew, ''T. splendidula'' ** Large treeshrew, ''T. tana'' ;Family Ptilocercidae: *Genus ''

Ptilocercus ''Ptilocercus'' is a genus of treeshrew and the sole member of the family Ptilocercidae. Taxonomy Today the genus (and family) is represented by a single species, the pen-tailed treeshrew ''(Ptilocercus lowii)''. However, this genus is very anc ...

'' **

Pen-tailed treeshrew The pen-tailed treeshrew (''Ptilocercus lowii'') is a treeshrew of the family Ptilocercidae native to southern Thailand, the Malay Peninsula, Borneo, and some Indonesian islands. It is the only living species in the genus ''Ptilocercus''. All ...

, ''P. lowii'' The Madras treeshrew (Anathana ellioti) by Davidraju img7.jpg, upright=0.8, Madras treeshrew (''Anathana ellioti'') The northern smooth-tailed treeshrew.jpg, upright=0.8, Northern smooth-tailed treeshrew (''Dendrogale murina'') Tupaia belangeri.JPG, upright=0.8,

(''Tupaia belangeri'') Stavenn Tupaia glis 00.jpg, upright=0.8,

(''T. glis'') Tupaia javanica.jpg, upright=0.8, Horsfield's treeshrew (''T. javanica'') Tupaia minor.jpg, upright=0.8,

(''T. minor'')

Fossil record

The fossil record of treeshrews is poor. The oldest putative treeshrew, '' Eodendrogale parva'', is from the

Middle Eocene The Eocene ( ) is a geological epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', ' Dawn') a ...

Henan Henan; alternatively Honan is a province in Central China. Henan is home to many heritage sites, including Yinxu, the ruins of the final capital of the Shang dynasty () and the Shaolin Temple. Four of the historical capitals of China, Lu ...

, China, but the identity of this animal is uncertain. Other fossils have come from the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

of Thailand, Pakistan, India, and

Yunnan Yunnan; is an inland Provinces of China, province in Southwestern China. The province spans approximately and has a population of 47.2 million (as of 2020). The capital of the province is Kunming. The province borders the Chinese provinces ...

, China, as well as the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58 Named fossil species include '' Prodendrogale yunnanica'', '' Prodendrogale engesseri'', and '' Tupaia storchi'' from Yunnan, '' Tupaia miocenica'' from Thailand, '' Palaeotupaia sivalicus'' from India and ''

Ptilocercus kylin ''Ptilocercus kylin'' is an extinct species of '' Ptilocercus'' that lived during the Rupelian stage of the Oligocene epoch. Distribution ''Ptilocercus kylin'' is known from the Lijiawa Mammalian Fossil locality of China China, offici ...

'' from Yunnan.

References

{{Taxonbar, from=Q231550 Fauna of Southeast Asia Extant Eocene first appearances