The round-tailed ground squirrel (''Xerospermophilus tereticaudus''), known as "Ardillón cola redonda" in Spanish, live in the desert of 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, Ne ...
and Northwestern Mexico. They are called "
ground squirrels
Ground squirrels are members of the squirrel family of rodents ( Sciuridae), which generally live on or in the ground, rather than trees. The term is most often used for the medium-sized ground squirrels, as the larger ones are more commonly known ...
" because they burrow in loose soil, often under
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 grou ...
trees and
creosote bushes.
Characteristics
Most round-tailed ground squirrels are very small. Weight at birth is approximately . Adults weigh around .
[AnAge entry for Spermophilus tereticaudus (HAGRID 03372)](_blank)
All have a long round tail and long, hairy hind feet. They have no fur markings, instead having a uniform sandy color, which matches the soil they burrow in. The underside of their body is usually a lighter shade. Round tailed squirrels average in length including the tail which is from long.
[Ernest, K., M. Mares. February 27, 1987. Mammalian Species. The American Society of Mammalogists.]
Xerospermophilus tereticaudus.webm, At Desert Botanical Garden
Desert Botanical Garden is a botanical garden located in Papago Park, at 1201 N. Galvin Parkway in Phoenix, central Arizona.
Founded by the Arizona Cactus and Native Flora Society in 1937 and established at this site in 1939, the garden now has ...
, Phoenix
Phoenix most often refers to:
* Phoenix (mythology), a legendary bird from ancient Greek folklore
* Phoenix, Arizona, a city in the United States
Phoenix may also refer to:
Mythology
Greek mythological figures
* Phoenix (son of Amyntor), a ...
Lifecycle
The
gestation period
In mammals, pregnancy is the period of reproduction during which a female carries one or more live offspring from implantation in the uterus through gestation. It begins when a fertilized zygote implants in the female's uterus, and ends once it ...
is 28 days. An average of 5.4 pups are born in each litter. They reach sexual maturity at 325 days. There is little information on the
longevity
The word " longevity" is sometimes used as a synonym for "life expectancy" in demography. However, the term ''longevity'' is sometimes meant to refer only to especially long-lived members of a population, whereas ''life expectancy'' is always d ...
of these animals but one wild born specimen lived to approximately 8.9 years in captivity.
They are prey animals for coyotes, badgers, hawks and snakes. Round-tailed ground-squirrels have also been found with the
Coccidian parasite ''Eimeria vilasi'', normally found in other rodents and Old World marmotine rodents.
Behavior
Ground squirrels are well-adapted to
desert
A desert is a barren area of landscape where little precipitation occurs and, consequently, living conditions are hostile for plant and animal life. The lack of vegetation exposes the unprotected surface of the ground to denudation. About on ...
life, as they mainly reside in the desert regions of the southwestern United States, northeastern Baja California, and northwestern Mexico, specifically in the state of Sonora.
They can stay active even on the hottest of days, although they do tend to limit their activity during the heat of the afternoon sun. They live underground in the winter, typically from late August or September until January or February. They go into
torpor
Torpor is a state of decreased physiological activity in an animal, usually marked by a reduced body temperature and metabolic rate. Torpor enables animals to survive periods of reduced food availability. The term "torpor" can refer to the time ...
, but do not
hibernate
Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It most ...
. Males are active first in late January as they start mating in March. Ground squirrels' activity cycle makes them not aggressive or competitive. Their main activities include caring for newborn, finding better protection for their resources, and reducing predation. They chase each other and nuzzle each other.
The greatest predator of the ground squirrel is a snake--the type of snake varying by the locality. As a result, ground squirrels have evolved to perform anti-snake displays to defend themselves. These squirrels tend to be put on a prominent display, specifically by moving their tail back-and-forth horizontally. They also approach the predator and sometimes kick some dirt at the snake.
Social structure
They have a semi-colonial social structure, and will alert others of impending danger with a high-pitched alarm call. But they will chase away other ground squirrels who get too close to their own burrow. The males are dominant during the breeding season (January through March). The females dominate during the raising of the young (March and April). However, recent studies suggest that they may have a matrilineal population structure with more socialization than anticipated.
This means that round-tailed ground squirrels may have a greater tendency to socialize within familial groups of female squirrels.
Diet
They are
omnivore
An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutr ...
s. The bulk of their diet is green vegetation, especially in the summer. They also eat seeds and insects (ants, termites, and grasshoppers). Most of their foods are chosen for high water content because of the shortage of available water in their environment. The average water content of the food they eat is 80%.
The squirrels prefer seeds and parts of grasses and flowers, but can climb into shrubs and trees for food.
References
External links
University of Michigan's Animal Diversity Web Spermophilus tereticaudus (round-tailed ground squirrel)
*
{{Taxonbar, from=Q21755532
Xerospermophilus
Mammals of Mexico
Mammals of the United States
Fauna of the Southwestern United States
Fauna of the Mojave Desert
Fauna of the Sonoran Desert
Fauna of the Colorado Desert
Fauna of the Yuma Desert
Natural history of Arizona
Natural history of Sonora
Mammals described in 1858