The rock squirrel (''Otospermophilus variegatus'') is a species of

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 ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Sciuridae 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 ...

. It is native to

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

and the

Southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural list of regions of the United States, region of the United States that includes Arizona and New Mexico, along with adjacen ...

, including southern Nevada, Utah, Colorado, Arizona, New Mexico, West Texas, and the panhandle of Oklahoma.{{Cite web, url=https://animaldiversity.org/accounts/Spermophilus_variegatus/, title="Spermophilus variegatus rock squirrel", last=Langstaff, first=Lucas, website=nhpbs.org, access-date=2019-10-11

Characteristics

Rock squirrels are one of the largest members of the family Sciuridae, with adults measuring up to 21 inches (53 cm) in length. In front and on top, the squirrel's coat is a speckled grayish brown; on the rear and bottom, the gray becomes a more mottled brownish-black tone. They have a marked light-colored ring around their eyes and pointed ears that project well above their heads. Rock squirrels have a long, bushy tail with white edges. Otospermophilus variegatus.webm, Alarm call Otospermophilus_variegatus.jpg, at Water Ranch Lake, AZ

Life history/behavior

The female rock squirrel has two litters a year, with three to nine young in each litter. The first litter is typically born from April to June, while the second is born in August or September. They are active in the early morning and late afternoons when the weather is warm; when very hot, they may estivate. They are social, and live in colonies with several females and one dominant male that fights other mature males to protect the group. Subordinate males lurk at the outer boundaries of the group. Rock squirrels dig burrows with their sharp claws and muscular legs. The burrows provide shelter, safety, living space, and food storage. Burrow systems can be complex and lengthy, as they are enlarged over a period of years. Entrances are usually hidden beneath rocks and can be wider than 3 inches. In the northern reach of their habitat, rock squirrels hibernate during the colder months of the year. In southern areas, rock squirrels may not hibernate at all.{{sfn, Marsh, 1994, p=B-153 They can withstand long periods of time without water, some even up to 100 days.{{sfn, Oaks, Kirkland, Schmidt, Young, 1987, p=6 When alarmed, they whistle a short, sharp, oscillating call.

Diet

The rock squirrel is predominantly a

herbivore A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...

, eating mostly leaves, stems, and seeds, and occasionally

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

s and small vertebrates. They also eat acorns, pine nuts, fruits of native plants, assorted grasses,

mesquite Mesquite is a common name for some plants in the genera ''Neltuma'' and '' Strombocarpa'', which contain over 50 species of spiny, deep-rooted leguminous shrubs and small trees. They are native to dry areas in the Americas. Until 2022, these ge ...

, juniper berries,

agave ''Agave'' (; ; ) is a genus of monocots native to the arid regions of the Americas. The genus is primarily known for its succulent and xerophytic species that typically form large Rosette (botany), rosettes of strong, fleshy leaves. Many plan ...

s and cacti. The primary invertebrates include grasshoppers, beetles and earthworms and the vertebrates include young wild turkeys and other fowl.{{Cite web, url=https://animaldiversity.org/accounts/Spermophilus_variegatus/, title=Spermophilus variegatus (rock squirrel), last=Langstaff, first=Lucas, website=Animal Diversity Web, language=en, access-date=2019-10-11 The rock squirrel may eat their own kind, scavenging the remains of squirrels that are already dead. Its diet changes with the seasons, accustoming itself to what is available locally. Rock squirrels forage for their food on a daily basis, by climbing trees and bushes or on the ground. They collect generous amounts of food items in their cheek pouches, which are quite large. One researcher counted 62 Gambel's oak acorns carried in one squirrel's pouch. These foraging trips are generally short-lived, usually only lasting about 12 minutes. Most foraging is done in the morning, to avoid the hotter parts of the day. They eat some of the food right away and bring a significant portion back to a lookout point or burrow, where they can safely consume or store the rest.{{cite web, url=http://animaldiversity.org/accounts/Spermophilus_variegatus/, title=ADW: Spermophilus variegatus: INFORMATION, work=Animal Diversity Web

Predators

A variety of snakes,

birds of prey Birds of prey or predatory birds, also known as (although not the same as) raptors, are hypercarnivorous bird species that actively predation, hunt and feed on other vertebrates (mainly mammals, reptiles and smaller birds). In addition to speed ...

, and other mammals (bobcats, ringtails, gray foxes, raccoons, coyotes, badgers, domestic cats and dogs) prey upon the rock squirrel. Humans have also been known to eat rock squirrels, but can also view them as pests, resulting in lethal and nonlethal removal. The rock squirrel displays a variety of antipredator behaviors. When close to a snake, they make menacing movements and even throw debris at the snake. They often feed, rest, and sunbathe in trees, high rocks, and stumps. This allows them to watch for predators and to communicate alarm calls to other squirrels. They also emit musky scent from their anal glands when disturbed by predators.

Geographic Range

Because of their specialized habitat requirements, there are only a few states in the US where these creatures can sustain themselves. These squirrels inhabit rocky mountains, canyon walls, cliffs, and steep rocky hills and only a few areas within North America contain such landscapes. These squirrels can be found throughout the southern US border along with Mexico in states like California, Arizona, Utah, Colorado, Oklahoma, New Mexico and parts of West Texas.{{cn, date=April 2023 Contrary to popular belief, in Mexico these squirrels are not found in eastern coastal lowlands, but they inhabit areas of Jalisco, Guerrero, Mexico, Morelos, Colima and Puebla. In the western edge of the range of these squirrels in the US, they mostly inhabit parts of southeasternmost corners of California, which includes some of the most arid areas in the entire state.

References

{{Reflist, 30em

Sources

* {{cite journal , first1=Emily C. , last1=Oaks, first2=Gordon L. , last2=Kirkland , first3=David F. , last3=Schmidt , first4=Paul J. , last4=Young , title=Spermophilus Variegatus (Erxleben, 1777): Rock Squirrel , journal=Mammalian Species , date=27 February 1987 , publisher=The American Society of Mammalogists , issue=272 , doi=10.2307/3503949, jstor=3503949 , doi-access=free * {{cite book , last=Marsh , first=Rex E. , chapter=Belding's, California, and Rock Ground Squirrels , title=Prevention and Control of Wildlife Damage , editor1-first=Scott E. , editor1-last=Hygnstrom , editor2-first=Robert M. , editor2-last=Timm , editor3-first=Gary E. , editor3-last=Larson , date=1994 , publisher=University of Nebraska-Lincoln , chapter-url=https://digitalcommons.unl.edu/icwdmhandbook/26/

External links

*{{Commons-inline, Otospermophilus variegatus, ''Otospermophilus variegatus''
Smithsonian rock squirrel articleThe American Society of Mammalogists species account

Arizona-Sonora Desert Museum
{{Marmotini nav {{Taxonbar, from=Q21727774, from2=Q1404317 Otospermophilus Rodents of Mexico Rodents of the United States Mammals described in 1777 Taxa named by Johann Christian Polycarp Erxleben Articles containing video clips Taxonomy articles created by Polbot