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

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

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Sciuridae Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrels. Squ ...

and is native to

Mexico Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...

and the

Southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, N ...

, 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.

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 Aestivation ( la, aestas (summer); also spelled estivation in American English) is a state of animal dormancy, similar to hibernation, although taking place in the summer rather than the winter. Aestivation is characterized by inactivity and a ...

. 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, March, p=2 2 They can withstand long periods of time without water, some even up to 100 days. {{sfn, Oaks, p=5 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 adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpar ...

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

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chorda ...

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

mesquite Mesquite is a common name for several plants in the genus '' Prosopis'', which contains over 40 species of small leguminous trees. They are native to dry areas in the Americas. They have extremely long roots to seek water from very far under gr ...

, juniper berries,

agave ''Agave'' (; ; ) is a genus of monocots native to the hot and arid regions of the Americas and the Caribbean, although some ''Agave'' species are also native to tropical areas of North America, such as Mexico. The genus is primarily known for ...

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 its 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.

Predators

A variety of snakes,

birds of prey Birds of prey or predatory birds, also known as raptors, are hypercarnivorous bird species that actively hunt and feed on other vertebrates (mainly mammals, reptiles and other smaller birds). In addition to speed and strength, these predat ...

, 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's very select states in the US where these creatures can sustain themselves. These squirrels inhabit rocky mountains, canyon walls, cliffs, and steep rocky hills and there's only a few areas within North America with such type of landscape. 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.{{Cite journal, last1=Makar, first1=A. B., last2=McMartin, first2=K. E., last3=Palese, first3=M., last4=Tephly, first4=T. R., date=June 1975, title=Formate assay in body fluids: application in methanol poisoning, url=https://www.sciencedirect.com/science/article/abs/pii/0006294475901477 , journal=Biochemical Medicine, volume=13, issue=2, pages=117–126, doi=10.1016/0006-2944(75)90147-7 , pmid=1 Contrary to popular belief, in Mexico these squirrels are not found 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

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 North America Mammals of Mexico Mammals of the United States Fauna of the Rocky Mountains Mammals described in 1777 Taxa named by Johann Christian Polycarp Erxleben Articles containing video clips Taxonomy articles created by Polbot