Treeshrew

{{short description|Order of mammals}} {{Automatic taxobox | name = Treeshrews<ref name=msw3>{{MSW3 Scandentia|id= 11900001|pages=104–109}}</ref> | status2 = CITES_A2 | status2_system = CITES | status2_ref = <ref>{{Cite web|title=Appendices {{!}} CITES|url=https://cites.org/eng/app/appendices.php|access-date=2022-01-14|website=cites.org}}</ref> | fossil_range = Middle Eocene – Recent | image = Spitzhörnchen.JPG | image_caption = ''Tupaia'' sp. | taxon = Scandentia | authority = Wagner, 1855 | subdivision_ranks = Families | subdivision = *Tupaiidae *Ptilocercidae | range_map = Treeshrew range.jpg | range_map_caption = Red: ''Tupaiidae'', blue: ''Ptilocercidae'', purple: both ''Tupaiidae'' and ''Ptilocercidae'' | range_map2 = Treeshrew species density.jpg | range_map2_caption = The distribution and density of treeshrew species. }}

The '''treeshrews''' (also called '''tree shrews''' or '''banxrings'''<ref>{{cite Americana |wstitle=Tree-shrew}}</ref>) are small mammals native to the tropical forests of South and Southeast Asia. They make up the entire order '''Scandentia''' ({{IPAc-en|s|k|æ|n|ˈ|d|ɛ|n|(|t|)|ʃ|ə}}; from Latin {{lang|la|scandere}} {{gloss|to climb}}),<ref>{{cite book|last1=Martin|first1=Robert E.| last2=Pine|first2=Robert H.|last3=DeBlase|first3=Anthony F.|title=A Manual of Mammalogy with Keys to Families of the World, Third Edition|url=https://books.google.com/books?id=kQEZAAAAQBAJ&pg=PA94|access-date=16 December 2024|year=2011|page=94|publisher=Waveland Press|isbn=978-1-47860-953-7}}</ref> which split into two families: the Tupaiidae (19 species, "ordinary" treeshrews), and the Ptilocercidae (one species, the pen-tailed treeshrew).

Though called 'treeshrews', and despite having previously been classified in Insectivora, they are not true shrews, and not all species live in trees. They are omnivores; among other things, treeshrews eat fruit. As fellow members of Euarchonta, treeshrews are closely related to primates, and have been used as an alternative to primates in experimental studies of myopia, psychosocial stress, and hepatitis.<ref>{{cite journal |last1=Cao |first1=J. |last2= Yang |first2=E.B. |last3=Su |first3=J.-J. |last4=Li |first4=Y. |last5=Chow |first5=P. |title=The tree shrews: Adjuncts and alternatives to primates as models for biomedical research |journal=Journal of Medical Primatology |year=2003 |volume=32 |issue=3 |pages=123–130 |url=http://www.unifr.ch/inph/vclab/assets/files/PDFs/Caoetal.pdf |access-date=1 January 2012 |doi=10.1034/j.1600-0684.2003.00022.x |pmid=12823622 |s2cid=16910445 }}</ref>

==Description== thumb|250px|Dentition of ''Tupaia''

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 of {{DentalFormula |upper=2.1.3.3 |lower=3.1.3.3}}<ref name=EoM>{{cite book |editor-last=Macdonald |editor-first=D. |author-last=Martin |author-first=Robert D. |year=1984 |title=The Encyclopedia of Mammals |publisher=Facts on File |location=New York, NY |pages=[https://archive.org/details/encyclopediaofma00mals_0/page/440 440–445] |isbn=978-0-87196-871-5 |df=dmy-all |url-access=registration |url=https://archive.org/details/encyclopediaofma00mals_0/page/440 }}</ref> They have a higher brain to body mass ratio than any other mammal, including humans,<ref>{{cite web |url=http://genome.wustl.edu/genomes/view/tupaia_belangeri |title=an article on Tupaia belangeri |department=The Genome Institute |publisher=Washington University |archive-url=https://web.archive.org/web/20100601201841/https://www.genome.wustl.edu/genomes/view/tupaia_belangeri |archive-date=2010-06-01 |df=dmy-all}}</ref> but high ratios are not uncommon for animals weighing less than {{convert|1|kg|lbs|abbr=on|sigfig=1}}.

Treeshrews have good vision, 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.<ref name=EoM/>

==Behavior== Treeshrews live in small family groups, which defend their territory from intruders. Most are diurnal, although the pen-tailed treeshrew is nocturnal.

They mark their territories using various scent glands or urine, depending on the particular species.

==Diet== Treeshrews are omnivorous, feeding on insects, small vertebrates, fruit, and seeds. Among other things, treeshrews eat ''Rafflesia'' 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.<ref>{{cite web |url=http://www.nbcnews.com/id/25908012/#.Vu6u9RXD_VI |archive-url=https://web.archive.org/web/20140315184721/http://www.nbcnews.com/id/25908012/#.Vu6u9RXD_VI |archive-date=March 15, 2014 |author-last=Moscowicz |author-first=Clara |year=2008 |title=Tiny tree shrew can drink you under the table |website=NBC News |df=dmy-all}}</ref><ref>{{cite journal| author=Wiens F, Zitzmann A, Lachance MA, Yegles M, Pragst F, Wurst FM | display-authors=etal| title=Chronic intake of fermented floral nectar by wild treeshrews. | journal=Proc Natl Acad Sci U S A | year= 2008 | volume= 105 | issue= 30 | pages= 10426–31 | pmid=18663222 | doi=10.1073/pnas.0801628105 | pmc=2492458| bibcode=2008PNAS..10510426W| doi-access=free}} </ref>

Treeshrews have also been observed intentionally eating foods high in capsaicin, a behavior unique among mammals other than humans. A single TRPV1 mutation reduces their pain response to capsaicinoids, which scientists believe is an evolutionary adaptation to be able to consume spicy foods in their natural habitats.<ref>{{Cite web |url=https://www.nationalgeographic.com/animals/article/tree-shrews-pain-chili-peppers-news |archive-url=https://web.archive.org/web/20180827075257/https://relay.nationalgeographic.com/proxy/distribution/public/amp/animals/2018/07/tree-shrews-pain-chili-peppers-news |archive-date=August 27, 2018 |title=See Why Tree Shrews Are Only the Second Known Mammal to Seek Spicy Food |website=nationalgeographic.com |language=en |access-date=2018-08-26}}</ref> Bornean montane pitcher plant species like ''Nepenthes lowii'' supplement their carnivorous diet with tree shrew droppings, which provide essential nitrogen in a mutualistic relationship. The plants facilitate this behavior by producing excess edible exudates on a leaf surface most easily reachable with the treeshrew's hindquarters above the opening of the pitcher.<ref name=clarke2009>{{cite journal | vauthors = Clarke CM, Bauer U, Lee CC, Tuen AA, Rembold K, Moran JA | title = Tree shrew lavatories: a novel nitrogen sequestration strategy in a tropical pitcher plant | journal = Biology Letters | volume = 5 | issue = 5 | pages = 632–5 | date = October 2009 | pmid = 19515656 | pmc = 2781956 | doi = 10.1098/rsbl.2009.0311 }}</ref><ref name="Chin-2010">{{cite journal | vauthors = Chin L, Moran JA, Clarke C | title = Trap geometry in three giant montane pitcher plant species from Borneo is a function of tree shrew body size | journal = The New Phytologist | volume = 186 | issue = 2 | pages = 461–70 | date = April 2010 | pmid = 20100203 | doi = 10.1111/j.1469-8137.2009.03166.x }}</ref><ref>{{cite journal | vauthors = Clarke C, Moran JA, Chin L | title = Mutualism between tree shrews and pitcher plants: perspectives and avenues for future research | journal = Plant Signaling & Behavior | volume = 5 | issue = 10 | pages = 1187–9 | date = October 2010 | pmid = 20861680 | pmc = 3115346 | doi = 10.4161/psb.5.10.12807 }}</ref> This adaptation is seen in the mature plant's aerial pitchers, not in the terrestrial ones produced by both juvenile and adult plants.<ref name=clarke2009/>

[[File:Murud N. lowii 20.jpg|thumb|upright=1.4|An upper pitcher of ''Nepenthes lowii'' ]] [[File:The Zoology of the voyage of H.M.S. Samarang, under the command of Captain Sir Edward Belcher, C.B., F.R.A.S., F.G.S., during the years 1843-1846 (8338415184).jpg|thumb|upright=0.8|Pen-tailed treeshrew (1850 depiction of ''Ptilocercus lowii'')]]

== Taxonomy == Treeshrews were moved from the order Insectivora into the order Primates because of certain internal similarities to primates (for example, similarities in the brain anatomy, highlighted by Sir Wilfrid Le Gros Clark), and classified as a "primitive prosimian", however they were soon split from the primates and moved into their own order. Taxonomists continue to refine the treeshrews' relations to primates and to other closely related clades.

Molecular phylogenetic studies have suggested that the treeshrews, with the primates and the flying lemurs (colugos), belong to the grandorder Euarchonta. According to this classification, the Euarchonta are sister to the Glires (lagomorphs and rodents), and the two groups are combined into the superorder Euarchontoglires.<ref>{{cite journal |last1=Janecka |first1=Jan E. |last2=Miller |first2=Webb |last3=Pringle |first3=Thomas H. |last4=Wiens |first4=Frank |last5=Zitzmann |first5=Annette |last6=Helgen |first6=Kristofer M. |last7=Springer |first7=Mark S. |last8=Murphy |first8=William J. |title=Molecular and genomic data identify the closest living relatives of the Primates |journal=Science |volume=318 |pages=792–794 |date=2007-11-02 |df=dmy-all |doi=10.1126/science.1147555 |pmid=17975064 |issue=5851 |bibcode=2007Sci...318..792J|s2cid=12251814 }}</ref> However, the alternative placement of treeshrews as sister to both Glires and Primatomorpha cannot be ruled out.<ref name=Zhou15/> 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.<ref>{{cite journal |last1=Meredith |first1=Robert W. |last2=Janečka |first2=Jan E. |last3=Gatesy |first3=John |last4=Ryder |first4=Oliver A. |last5=Fisher |first5=Colleen A. |last6=Teeling |first6=Emma C. |last7=Goodbla |first7=Alisha |last8=Eizirik |first8=Eduardo |last9=Simão |first9=Taiz L. L. |date=2011-10-28 |df=dmy-all |title=Impacts of the Cretaceous terrestrial revolution and KPg extinction on mammal diversification |journal=Science |volume=334 |issue=6055 |pages=521–524 |doi=10.1126/science.1211028 |issn=0036-8075 |pmid=21940861 |bibcode=2011Sci...334..521M|s2cid=38120449 }}</ref><ref name=Zhou15>{{cite journal |last1=Zhou |first1=Xuming |last2=Sun |first2=Fengming |last3=Xu |first3=Shixia |last4=Yang |first4=Guang |last5=Li |first5=Ming |date=2015-03-01 |df=dmy-all |title=The position of tree shrews in the mammalian tree: Comparing multi-gene analyses with phylogenomic results leaves monophyly of Euarchonta doubtful |journal=Integrative Zoology |volume=10 |issue=2 |pages=186–198 |doi=10.1111/1749-4877.12116 |pmid=25311886 |issn=1749-4877}}</ref>

{{clade |style=font-size:90%;line-height:85% |label1=Euarchontoglires |1={{Clade |1={{Clade |1='''Scandentia''' (treeshrews) |label2=Glires |2={{Clade |1=Lagomorpha (rabbits, hares, pikas) |2=Rodentia (rodents) }} }}

|label2=Primatomorpha |2={{Clade |1=Dermoptera (colugos) |2={{Clade |1=†Plesiadapiformes |2=Primates }} }} }} }}

Several other arrangements of these orders have been proposed in the past, and the above tree is only one of several proposals.<ref>{{cite journal |last1=Pettigrew |first1=J.D. |last2=Jamieson |first2=B.G. |last3=Robson |first3=S.K. |last4=Hall |first4=L.S. |last5=McAnally |first5=K.I. |last6=Cooper |first6=H.M. |year=1989 |title=Phylogenetic relations between microbats, megabats, and primates |series=Mammalia: Chiroptera and Primates |journal=Philosophical Transactions of the Royal Society B |url=http://rstb.royalsocietypublishing.org/content/royptb/325/1229/local/back-matter.pdf |volume=325 |issue=1229 |pages=489–559 |doi=10.1098/rstb.1989.0102 |pmid=2575767 |bibcode=1989RSPTB.325..489P |df=dmy-all}}</ref> The exact phylogenetic position is not yet considered resolved: it may be a sister of Glires, Primatomorpha,<ref name="LinChen2014">{{cite journal|last1= Lin|first1=J.|last2= Chen|first2=G.|last3= Gu|first3=L.|last4= Shen|first4=Y.|last5= Zheng|first5=M.|last6= Zheng|first6=W.|last7= Hu|first7=X.|last8= Zhang|first8=X.|last9 =Qiu|first9=Y.|last10= Liu|first10=X.|last11= Jiang|first11=C.|title= Phylogenetic affinity of tree shrews to Glires is attributed to fast evolution rate|journal= Molecular Phylogenetics and Evolution |volume= 71|year= 2014|pages= 193–200|doi= 10.1016/j.ympev.2013.12.001|pmid=24333622}}</ref> or Dermoptera, or separate from and sister to all other Euarchontoglires.<ref>{{cite journal |last1=Foley |first1=Nicole M. |last2=Springer |first2=Mark S. |last3=Teeling |first3=Emma C. |date=2016-07-19 |df=dmy-all |title=Mammal madness: Is the mammal tree of life not yet resolved? |journal=Philosophical Transactions of the Royal Society B |volume=371 |issue=1699 |article-number=20150140 |doi=10.1098/rstb.2015.0140 |issn=0962-8436 |pmc=4920340 |pmid=27325836}}</ref><ref>{{cite journal |last1=Kumar |first1=Vikas |last2=Hallström |first2=Björn M. |last3=Janke |first3=Axel |date=2013-04-01 |title=Coalescent-based genome analyses resolve the early branches of the Euarchontoglires |journal=PLOS ONE |volume=8 |issue=4 |article-number=e60019 |doi=10.1371/journal.pone.0060019 |issn=1932-6203 |pmc=3613385 |pmid=23560065 |df=dmy-all|bibcode=2013PLoSO...860019K|doi-access=free }}</ref> Shared short interspersed nuclear elements (SINEs) offer evidence for Scandentia belonging to the Euarchonta group:<ref>{{Cite journal |last1=Kriegs |first1=Jan Ole |last2=Churakov |first2=Gennady |last3=Jurka |first3=Jerzy |last4=Brosius |first4=Jürgen |last5=Schmitz |first5=Jürgen |date=2007-02-20 |title=Evolutionary history of 7SL RNA-derived SINEs in Supraprimates |url=https://linkinghub.elsevier.com/retrieve/pii/S0168952507000376 |journal=Trends in Genetics |language=en |volume=23 |issue=4 |pages=158–161 |doi=10.1016/j.tig.2007.02.002|pmid=17307271 |url-access=subscription }}</ref>

{{Clade|{{Clade | label1=Glires | 1={{Clade | 1=Lagomorpha (rabbits, hares, pikas) | 2=Rodentia (rodents) }} | label2=Euarchonta | 2={{Clade | 1='''Scandentia''' (treeshrews) | label2=Primatomorpha | 2={{Clade | 1={{Clade | 1=Dermoptera (colugos) }} | 2={{Clade | 1=Primates (†Plesiadapiformes, Strepsirrhini, Haplorrhini)}} }} }} }}|label1=Euarchontoglires}}

===Order Scandentia=== {{main|List of scandentians}} The 23 species are placed in four genera, which are divided into two families. The majority are in the "ordinary" treeshrew family, Tupaiidae, but one species, the pen-tailed treeshrew, is different enough to warrant placement in its own family, Ptilocercidae; the two families are thought to have separated 60 million years ago.<ref name="Roberts2011" /> The former Tupaiidae genus ''Urogale'' was disbanded in 2011 when the Mindanao treeshrew was moved to ''Tupaia'' based on a molecular phylogeny.<ref name="Roberts2011"> {{cite journal|last1= Roberts|first1=T.E.|last2= Lanier|first2=H.C.|last3= Sargis|first3=E.J.|last4= Olson|first4=L.E.|title= Molecular phylogeny of treeshrews (Mammalia: Scandentia) and the timescale of diversification in Southeast Asia|journal= Molecular Phylogenetics and Evolution|volume= 60|issue= 3|year= 2011|pages= 358–372|doi= 10.1016/j.ympev.2011.04.021|pmid=21565274}} </ref>

;Family Tupaiidae: *Genus ''Anathana'' ** Madras treeshrew, ''A. ellioti''

*Genus ''Dendrogale'' ** Bornean smooth-tailed treeshrew, ''D. melanura'' ** Northern smooth-tailed treeshrew, ''D. murina''

*Genus ''Tupaia'' ** Northern treeshrew, ''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, ''T. glis'' ** Slender treeshrew, ''T. gracilis'' ** Javan treeshrew, ''T. hypochrysa'' ** Horsfield's treeshrew, ''T. javanica'' ** Long-footed treeshrew, ''T. longipes'' ** Pygmy treeshrew, ''T. minor'' ** Mountain treeshrew, ''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'' ** Pen-tailed treeshrew, ''P. lowii''

== Fossil record == The fossil record of treeshrews is poor. The oldest putative treeshrew, ''Eodendrogale parva'', is from the Middle Eocene of Henan, China, but the identity of this animal is uncertain. Other fossils have come from the Miocene of Thailand, Pakistan, India, and Yunnan, China, as well as the Pliocene of India. Most belong to the family Tupaiidae; one fossil species described from the Oligocene of Yunnan is thought to be closer to the pen-tailed treeshrew.<ref name="Li2016">{{cite journal|last1= Li|first1=Q.|last2= Ni|first2=X.|title=An early Oligocene fossil demonstrates treeshrews are slowly evolving "living fossils"|journal= Scientific Reports|volume= 6|issue= 1|year= 2016|article-number=18627|doi= 10.1038/srep18627|pmid=26766238|pmc=4725336|bibcode=2016NatSR...618627L |doi-access= free}}</ref>

Named fossil species include ''Prodendrogale yunnanica'', ''Prodendrogale engesseri'', and ''Tupaia storchi'' from Yunnan, ''Tupaia miocenica'' from Thailand, ''Palaeotupaia sivalicus'' from India<ref name=NiQiu2012>{{Cite journal |last1=Ni |first1=X. |last2=Qiu |first2=Z. |title=Tupaiine tree shrews (Scandentia, Mammalia) from the Yuanmou ''Lufengpithecus'' locality of Yunnan, China |doi=10.1007/s13358-011-0029-0 |journal=Swiss Journal of Palaeontology |volume=131 |pages= 51–60 |year=2012 |s2cid=85271080 |df=dmy-all|doi-access=free }}</ref> and ''Ptilocercus kylin'' from Yunnan.<ref name="Li2016" />

==See also== * ''Purgatorius'' * Shrew-faced squirrel

==References== {{Reflist}}

Category:Treeshrews Category:Fauna of Southeast Asia Category:Extant Eocene first appearances