View source for Ground squirrel

{{Short description|Type of ground-dwelling rodent}}
{{Automatic taxobox
| name = Ground squirrel
| fossil_range = [[Rupelian|Early Oligocene]] to recent
| image = Yer sincabı.jpg
| image_caption = Ground squirrel in [[Turkey]]
| taxon = Marmotini
| authority = [[Reginald Innes Pocock|Pocock]], 1923
| subdivision_ranks = [[Genera]]
| subdivision = 
''[[Palaeosciurus]]'' ([[fossil]])<BR>
''[[Sciurotamias]]''<BR>
''[[Spermophilinus]]'' (fossil)<BR>
''[[Ammospermophilus]]''<BR>
''[[Spermophilus]]''<BR>
''[[Notocitellus]]''<BR>
''[[Otospermophilus]]''<BR>
''[[Callospermophilus]]''<BR>
''[[Xerospermophilus]]''<BR>
''[[Cynomys]]''<BR>
''[[Poliocitellus]]''<BR>
''[[Ictidomys]]''<BR>
''[[Arctomyoides]]'' (fossil)<BR>
''[[Miospermophilus]]'' (fossil)<BR>
''[[Paenemarmota]]'' (fossil)<BR>
''[[Palaearctomys]]'' (fossil)<BR>
''[[Protospermophilus]]'' (fossil)<BR>
''[[Marmota]]''<BR>
''[[Eutamias]]''<BR>
''[[Neotamias]]''<BR>
''[[Nototamias]]'' (fossil)<BR>
''[[Tamias]]''<BR>
''[[Urocitellus]]''<BR>
and see [[#Subtribes and genera|text]]
}}
'''Ground squirrels''' are [[rodent]]s of the [[squirrel]] family ([[Sciuridae]]) that generally live on the ground or in [[burrow]]s, rather than in trees like the [[tree squirrel]]s. The term is most often used for the medium-sized ground squirrels, as the larger ones are more commonly known as [[marmots]] (genus ''Marmota'') or [[prairie dogs]], while the smaller and less bushy-tailed ground squirrels tend to be known as [[chipmunk]]s (genus ''Tamias'').

Together, they make up the "marmot [[Tribe (biology)|tribe]]" of squirrels, '''Marmotini''', a [[clade]] within the large and mainly ground squirrel [[subfamily]] [[Xerinae]], and containing six living [[genera]]. Well-known members of this largely [[Holarctic]] group are the [[marmot]]s (''Marmota''), including the American [[groundhog]], the [[chipmunk]]s, the [[suslik]]s (''Spermophilus''), and the [[prairie dog]]s (''Cynomys''). They are highly variable in size and [[Morphology (biology)|habitus]], but most are remarkably able to rise up on their hind legs and [[upright posture|stand fully erect]] comfortably for prolonged periods. They also tend to be far more gregarious than other squirrels, and many live in colonies with complex social structures. Most Marmotini are rather short-tailed and large squirrels. At up to {{cvt|8|kg}} or more, certain marmots are the heaviest squirrels.<ref name="Krystufek2013">{{cite journal | author1=Kryštufek, B. | author2=B. Vohralík | year=2013 | title=Taxonomic revision of the Palaearctic rodents (Rodentia). Part 2. Sciuridae: Urocitellus, Marmota and Sciurotamias | journal=Lynx, N. S. (Praha) | volume=44 | pages=27–138 }}</ref><ref name="Armitage2002">{{cite book | author1=Armitage, K.B. | author2=Blumstein, D.T. | year=2002 | chapter=Body-mass diversity in marmots. Holarctic marmots as a factor of biodiversity | editor1=K.B. Armitage | editor2=V.Yu. Rumiantsev | title=Holarctic Marmots as a Factor of Biodiversity | publisher=ABF Publishing House | pages=22–32 }}</ref>

The [[chipmunk]]s of the genus ''Tamias'' frequently spend time in trees. Also closer to typical squirrels in other aspects, they are occasionally considered a tribe of their own (Tamiini).<ref>Steppan ''et al.'' (2004)</ref>

==Evolution and systematics==
[[File:Squirrel Mummy.jpg|thumb|left|20,000-year-old [[Arctic ground squirrel]] [[mummy]]]]

''[[Palaeosciurus]]'' from [[Europe]] is the oldest known ground squirrel species, and it does not seem to be particularly close to any of the two to three living lineages (subtribes) of Marmotini. The oldest fossils are from the [[Rupelian|Early Oligocene]], more than 30 [[Myr|million years ago]] (Mya), but the genus probably persisted at least until the mid-[[Miocene]], some 15 Mya.

Where the Marmotini originated is unclear. The subtribes probably diverged in the early to mid-[[Oligocene]], as primitive marmots and chipmunks are known from the [[Late Oligocene]] of North America. The [[fossil record]] of the "true" ground squirrels is less well known, beginning only in the mid-Miocene, when modern susliks and prairie dogs are known to have inhabited their present-day range already.

Whether the Marmotini dispersed between North America and Eurasia via "[[Oceanic dispersal|island-hopping]]" across the [[Bering Straits]] or the [[Greenland]] region—both of which were temperate [[habitat]] at that time—and from which continent they dispersed to which, or if both continents brought forth distinct subtribes which then spread to the other, is not known and would probably require more fossil material to be resolved. In any case, the fairly comprehensive fossil record of Europe—at the relevant time separated from Asia by the [[Turgai Sea]]—lacks ancient Marmotini except the indeterminate ''Palaeosciurus'', which might be taken to indicate an East Asian or western North American origin with trans-Beringia dispersal being the slightly more satisfying hypothesis. This is also supported by the enigmatic Chinese genus ''[[Sciurotamias]]'', which may be the most ancient living lineage of this group, or—if the chipmunks are not included here—close to the common ancestor of the Tamiini and the Marmotini ''sensu stricto''.

In any case, expansion of the Marmotini to Africa was probably prevented by [[competitive exclusion]] by their close relatives the [[Protoxerini]] and [[Xerini]]—the native terrestrial and palm squirrels of that continent, which must have [[evolved]] at the same time as the Marmotini did.

=== Size ===
Ground squirrels can measure anywhere from about {{convert|7.2|in|cm}} in height up to nearly {{convert|30|in|cm}}. They can weigh between {{convert|0.09|lbs|kg}} and {{convert|24|lbs|kg}}.<ref>{{Cite book|last=Karels|first=Tim|title=Grzimek's Animal Life Encyclopedia (Vol. 16: Mammals V. 2nd ed.)|publisher=Gale|year=2004|pages=143}}</ref>

=== Habitat ===
Open areas including rocky outcrops, fields, pastures, and sparsely wooded hillsides comprise their habitat.<ref>National Audubon Society Field Guide to Mammals</ref> Ground squirrels also live in grassy areas such as pastures, golf courses, cemeteries, and parks.

=== Defense mechanisms ===
Ground squirrels have developed several defense mechanisms to protect themselves from predators. When threatened, they emit high-pitched warning calls to alert others in their colony. This alarm call serves as an early warning system, allowing nearby squirrels to seek cover. The squirrels spend about one-third of their time standing to watch and when a predator is in sight, they stop and watch 60% of the time.<ref>{{Cite journal |last1=van der Marel |first1=Annemarie |last2=Marel |first2=Annemarie van der |last3=Waterman |first3=Jane M. |last4=López-Darias |first4=Marta |date=2021-10-16 |title=Barbary ground squirrels do not have a sentinel system but instead synchronize vigilance |url=https://www.technologynetworks.com/neuroscience/news/ground-squirrels-early-warning-system-is-revealed-355313 |journal=Behavioral Ecology and Sociobiology |language=en |volume=75 |issue=11 |pages=153 |doi=10.1007/s00265-021-03094-1 |bibcode=2021BEcoS..75..153V |issn=1432-0762|url-access=subscription |hdl=10261/253365 |hdl-access=free }}</ref> Ground squirrels are also known for their burrowing behavior. They have intricate tunnel systems with multiple entrances, which provide escape routes from predators. When a threat approaches, they quickly retreat underground, where they are safe from most predators. Their burrows are designed with multiple chambers and ranges between {{convert|5|and|30|ft}},<ref>{{Cite web |title=Ground Squirrel / Home and Landscape / UC Statewide IPM Program (UC IPM) |url=https://ipm.ucanr.edu/home-and-landscape/ground-squirrel/pest-notes/#:~:text=California%20ground%20squirrels%20live%20in,between%205%20and%2030%20feet. |access-date=2023-10-25 |website=ipm.ucanr.edu}}</ref> making it challenging for predators to reach them. This combination of vocal warnings and burrow construction makes ground squirrels highly adapted to evade danger and survive in the wild.[[File:California Ground Squirrel.jpg|thumb|[[California ground squirrel]] (''Otospermophilus beecheyi'') in a tree]]

=== Diet ===
Ground squirrels are omnivorous, and not only eat a diet rich in fungi, nuts, fruits, and seeds, but also occasionally eat insects, eggs, and other small animals.<ref>{{cite web|title=Squirrels: Diet, Habits & Other Facts|website=[[Live Science]] |date=27 June 2014 |url=http://www.livescience.com/28182-squirrels.html}}</ref>

===Subtribes and genera===
[[File:Marmot-edit1.jpg|thumb|right|Watchful "rock chuck" or [[yellow-bellied marmot]] (''Marmota flaviventris'') atop [[Mount Dana]], [[Yosemite National Park]] in California]]
[[Basal (evolution)|Basal]] and ''[[incertae sedis]]'' genera
* {{extinct}}''[[Palaeosciurus]]'' ([[fossil]])<!-- Palaeontology 46(6): 1133-1149 -->
* ''[[Callospermophilus]]'' 
* ''[[Notocitellus]]''
* ''[[Otospermophilus]]'' (American rock squirrels)
* ''[[Poliocitellus]]'' (Franklin's ground squirrel)
* ''[[Sciurotamias]]'' (Chinese rock squirrels)
* ''[[Urocitellus]]''
* ''[[Xerospermophilus]]''
'''Subtribe Tamiina''': [[chipmunks]] (might be full tribe)
* ''[[Eutamias]]''
* ''[[Neotamias]]''
* {{extinct}}''[[Nototamias]]'' (fossil)
* ''[[Tamias]]''
'''Subtribe Marmotina''': marmots and prairie dogs
* {{extinct}}''[[Arctomyoides]]'' (fossil)
* {{extinct}}''[[Miospermophilus]]'' (fossil)
* {{extinct}}''[[Paenemarmota]]'' (fossil)
* {{extinct}}''[[Palaearctomys]]'' (fossil)
* {{extinct}}''[[Protospermophilus]]'' (fossil)
* ''[[Marmota]]''
* ''[[Cynomys]]'' (prairie dogs)
'''Subtribe Spermophilina''': true ground squirrels
* {{extinct}}''[[Spermophilinus]]'' (fossil)
* ''[[Ammospermophilus]]''
* ''[[Ictidomys]]'': [[Thirteen-lined ground squirrel]] and related species
* ''[[Spermophilus]]''

==Cladogram==

Below is a partial [[cladogram]] of ground squirrels (tribe [[Marmotini]], but excluding the Tamiina subtribe and some basal genera) derived from maximum parsimony analysis.{{sfn|Helgen|Cole|Helgen|Wilson|2009|p=274}}

{{clade| style=font-size:85%; line-height:85%
|1={{clade
 |1={{clade
  |label1=''[[Notocitellus]]''
  |1={{clade
   |1=''N. adocetus''
   |2=''N. annulatus'' }}
  |label2=''[[Ammospermophilus]]''
  |2={{clade
   |1=''A. harrisii''
   |2={{clade
    |1=''A. leucurus''
    |2={{clade
     |1=''A. harrisii''
     |2=''A. interpres'' }} }} }} }}
 |2={{clade
  |1={{clade
   |label1=''[[Otospermophilus]]''
   |1={{clade
    |1={{clade
     |1=''O. atricapillus''
     |2=''O. beecheyi'' }}
    |2=''O. variegatus'' }}
   |label2=''[[Callospermophilus]]''
   |2={{clade
    |1=''C. saturatus''
    |2={{clade
     |1=''C. lateralis''
     |2=''C. madrensis'' }} }} }}
  |2={{clade
   |label1=''[[Marmota]]''
   |1={{clade
    |1=''M. monax''
    |2=''M. marmota''
    |3={{clade
     |1=''M. flaviventris''
     |2={{clade
      |1=''M. caligata''
      |2={{clade
       |1=''M. olympus''
       |2=''M. vancouveriensis'' }} }} }}
    |4={{clade
     |1={{clade
      |1=''M. broweri''
      |2={{clade
       |1=''M. menzbieri''
       |2=''M. caudata'' }} }}
     |2={{clade
      |1={{clade
       |1=''M. baibacina''
       |2=''M. bobak'' }}
      |2={{clade
       |1=''M. camtschatica''
       |2={{clade
        |1=''M. himalayana''
        |2=''M. sibirica'' }} }} }} }} }} }} }} }}
   |2={{clade
    |label1=''[[Spermophilus]]''
    |1={{clade
     |1={{clade
      |1=''S. musicus''
      |2={{clade
       |1=''S. pygmaeus''
       |2={{clade
        |1=''S. major''
        |2=''S. pygmaeus'' }} }} }}
     |2={{clade
      |1={{clade
       |1={{clade
        |1=''S. dauricus''
        |2=''S. xanthopyrmnus'' }}
       |2=''S. suslicus'' }}
      |2={{clade
       |1=''S. citellus''
       |2={{clade
        |1=''S. relictus''
        |2={{clade
         |1=''S. erythrogenys''
         |2={{clade
          |1=''S. citellus''
          |2={{clade
           |1=''S. pallidicauda''
           |2={{clade
            |1=''S. fulvus''
            |2={{clade
             |1=''S. erythrogenys''
             |2=''S. major'' }} }} }} }} }} }} }} }} }}
    |2={{clade
     |1={{clade
      |label1=''[[Ictidomys]]''
      |1={{clade
       |1=''I. mexicanus''
       |2={{clade
        |1=''I. parvidens''
        |2=''I. tridecemlineatus'' }} }}
      |2={{clade
       |label1=''[[Poliocitellus]]''
       |1=''P. franklinii''
       |2={{clade
        |label1=''[[Cynomys]]''
        |1={{clade
         |1={{clade
          |1=''C. ludovicianus''
          |2=''C. mexicanus'' }}
         |2={{clade
          |1=''C. parvidens''
          |2={{clade
           |1=''C. gunnisoni''
           |2=''C. leucurus'' }} }} }}
        |label2=''[[Xerospermophilus]]''
        |2={{clade
         |1={{clade
          |1=''X. mohavensis''
          |2=''X. tereticaudus'' }}
         |2={{clade
          |1=''X. spilosoma''
          |2={{clade
           |1=''X. perotensis''
           |2=''X. spilosoma'' }} }} }} }} }} }}
    |label2=''[[Urocitellus]]''
    |2={{clade
     |1=''U. townsendii''
     |2={{clade
      |1=''U. washingtonii''
      |2={{clade
       |1={{clade
        |1=''U. brunnenus''
        |2={{clade
         |1=''U. townsendii''
         |2={{clade
          |1=''U. mollis''
          |2=''U. townsendii'' }} }} }}
       |2={{clade
        |1={{clade
         |1=''U. armatus''
         |2=''U. beldingi'' }}
        |2={{clade
         |1=''U. columbianus''
         |2={{clade
          |1=''U. undulatus''
          |2={{clade
           |1=''U. parryii''
           |2={{clade
            |1=''U. elegans''
            |2=''U. richardsonii'' }}
           |3=''U. parryii'' }} }} }} }} }} }} }} }} }} }}

==See also==
* [[Tree squirrel]]
* [[Xerini]]—the related "ground squirrels" of Asia and Africa

==References==
{{Reflist}}

==Further reading==
* {{cite journal|last1=Helgen |first1=Kristofer M. |last2=Cole |first2=F. Russell |last3=Helgen |first3=Lauren E. |last4=Wilson |first4=Don E. |title=Generic Revision in the Holarctic Ground Squirrel Genus Spermophilus |journal=Journal of Mammalogy |date=April 2009 |volume=90 |issue=2 |pages=270–305 |doi=10.1644/07-MAMM-A-309.1 |s2cid=28483038 |doi-access=free }}
* {{aut|Steppan, Scott J.; Storz, B.L. & Hoffmann, R.S.}} (2004): "Nuclear DNA phylogeny of the squirrels (Mammalia: Rodentia) and the evolution of arboreality from c-myc and RAG1". ''[[Molecular Phylogenetics and Evolution|Mol. Phyl. Evol.]]'' '''30'''(3): 703–719. <small>{{doi|10.1016/S1055-7903(03)00204-5}}</small> [http://bio.fsu.edu/~steppan/Steppan_et_al_Sciuridae.pdf PDF fulltext]
* {{aut|Thorington, R.W. & Hoffmann, R.S.}} (2005): Family Sciuridae. In: ''Mammal Species of the World—A Taxonomic and Geographic Reference'': 754–818. Johns Hopkins University Press, Baltimore.

==External links==
{{Commons category|Marmotini}}
* [https://web.archive.org/web/19970215003617/http://www.etc-etc.com/sqrlinfo.htm About California Ground Squirrels]

{{Marmotini nav}}

{{Taxonbar|from=Q389250}}

{{DEFAULTSORT:Ground Squirrel}}
[[Category:Ground squirrels| 01]]
[[Category:Rodents of Asia]]
[[Category:Rodents of North America]]
[[Category:Extant Rupelian first appearances]]
[[Category:Taxa named by R. I. Pocock]]