Horse-tailed squirrel

{{Short description|Species of rodent}}

{{Speciesbox

| image = Pferdeschwanzhörnchen.jpg

| status = NT

| status_system = IUCN3.1

| status_ref = {{cite iucn |author=Meijaard, E. |date=2017 |title=Sundasciurus hippurus |volume=2017 |page=e.T21155A22250415 |doi=10.2305/IUCN.UK.2017-2.RLTS.T21155A22250415.en |access-date=12 November 2021}}

| genus = Sundasciurus

| species = hippurus

| authority = (I. Geoffroy, 1831)

| subdivision_ranks = Subspecies

| subdivision_ref = {{cite book|last1=Thorington|first1=R.W. Jr.|last2=Hoffmann|first2=R.S.|year=2005|pages=754–818|editor1-last=Wilson|editor1-first=D.E.|editor2-last=Reeder|editor2-first=D.M|url=http://www.bucknell.edu/msw3|chapter=Family Sciuridae: Sundasciurus (Aletesciurus) hippurus|chapter-url=https://www.departments.bucknell.edu/biology/resources/msw3/browse.asp?id=12400646|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}}

| subdivision =

• S. h. hippurus
• S. h. borneensis
• S. h. pryeri
• S. h. hippurosus
• S. h. ornatus

| synonyms =

| range_map = Range_Sundasciurus_hippurus.png

}}

The horse-tailed squirrel (Sundasciurus hippurus) is a species of rodent in the family Sciuridae. It is found throughout the islands of Borneo and Sumatra, as well as the southern half of the Malay Peninsula, which includes the entire nations of Brunei and Malaysia, as well as some areas of Indonesia and Thailand. There was a mention of this squirrel being found in Vietnam in 1831 (I. Geoffroy, 1831), but subsequent descriptions of this squirrel's range have not included that nation.