The Thirteen-lined Ground Squirrel (Ictidomys tridecemlineatus), also known as the striped gopher, leopard ground squirrel, squinney, (formerly known as the leopard-spermophile in the age of Audubon), is a ground squirrel that is widely distributed over grasslands and prairies of North America.

It is brownish, with 13 alternating brown and whitish longitudinal lines (sometimes partially broken into spots) on its back and sides, creating rows of whitish spots within dark lines.

This species has usually been placed in the genus Spermophilus with about 40 other species. As this large genus is paraphyletic to prairie dogs, marmots, and antelope squirrels, Kristofer Helgen and colleagues have split it into eight genera, placing the thirteen-lined ground squirrel in Ictidomys with two other species.

The thirteen-lined ground squirrel is strictly diurnal and is especially active on warm days. A solitary or only somewhat colonial hibernator, it often occurs in aggregations in suitable habitats.

In late summer, it puts on a heavy layer of fat and stores some food in its burrow. It enters its nest in October (some adults retire much earlier), rolls into a stiff ball, and decreases its respiration from between 100 and 200 breaths per minute to one breath about every five minutes. It emerges in March or early April.

The burrow may be 15 to 20 feet (4.6 to 6.1 metres) long, with several side passages. Most of the burrow is within one to two feet (about half a meter) of the surface, with only the hibernation nest in a special deeper section. Shorter burrows are dug as hiding places. This ground squirrel's home range is two to three acres (0.8 to 1.2 ha).

Late in life, naturalist John James Audubon made a final expedition to the western plains in search of four-footed mammals. These striped ground squirrels would be tempting prey for many birds, especially hawks and owls. After the squirrels had left, burrowing owls might take over their underground dens.

Its primary diet includes grass and weed seeds, caterpillars, grasshoppers, and crickets, but it may also eat mice and shrews; it will viciously attack and consume cicadas if able to catch them. This squirrel sometimes damages gardens by digging burrows and eating vegetables, but also devours weed seeds and harmful insects.

It is well known for standing upright to survey its domain, diving down into its burrow when it senses danger, then sometimes poking out its nose and giving a bird-like trill. The "trill" is an alarm call that is most often used by females to warn nearby relatives. It has a maximum running speed of 8 mph (13 km/h) and reverses direction if chased.

Thirteen-lined Ground Squirrel (Ictidomys tridecemlineatus) - Pawnee National Grasslands, Colorado

The Rio Grande Ground Squirrel (Ictidomys parvidens) is a species of squirrel in the family Sciuridae. It is found in the south-western United States (Texas and New Mexico) and in north-eastern Mexico.

The Rio Grande ground squirrel was formerly considered to be a subspecies of the Mexican ground squirrel and, along with the other species of the genus Ictidomys, was classified in the much larger genus Spermophilus, until DNA sequencing of the cytochrome b gene showed that this group was paraphyletic to the prairie dogs and marmots, and could therefore no longer be retained as a single genus. As a result, Ictidomys is now considered as a genus in its own right.

Rio Grande Ground Squirrel (Ictidomys parvidens) - Carlsbad New Mexico

The Spotted Ground Squirrel (Xerospermophilus spilosoma) is a species of ground squirrel in the rodent family Sciuridae. It is found throughout Mexico and the central and western United States. Characterized by a white spotted back, the spotted ground squirrel is one of the smallest squirrels found in North America. They are mainly herbivorous, but also eat insects. A burrowing mammal, the spotted ground squirrel will make tunnels to store its food, as well as shelter and hibernation quarters.

The spotted ground squirrel is one of the smallest squirrels to inhabit the northern hemisphere. It has many white linear dorsal spots, as well as a white underbelly. Coloration of the rest of its body varies greatly and can be different shades of brown, black, gray and white. Its skull resembles that of the thirteen-lined ground squirrel, but is slightly broader in the interorbital and rostral regions. A unique characteristic of the skull is the presence of especially large auditory bullae. X. spilosoma has two pelages and molts each year. Adults emerging from hibernation usually display thicker pelages, which are shed by the springtime. Juveniles tend to have darker pelages than their adult counterparts. Fur color can be influenced by environmental surrounds, and it has been found that populations in soil rich areas tend to have darker colorings than grassland living populations.

The spotted ground squirrel can range from south central South Dakota, through Nebraska where it inhabits sand hills present there. It's also found in eastern Colorado, northwestern Oklahoma, western Texas, eastern Arizona, western Kansas, the large majority of New Mexico and the southeastern part of Utah. Mexico species distribution is limited to south and central Mexico. It is generally found within areas of deep sand soils where vegetation is sparse and scattered, aligning with the environments of the distributive areas it is found in. Being a burrowing animal, the spotted ground squirrel will inhabit sand hills and dunes where it makes it home and has even been found to dwell within abandoned prairie dog burrows. Spotted ground squirrel burrows are usually found on short grass mesa's or along the banks of rivers. They prefer lighter, more sparse soil to create their burrows with and this is why they dwell in arid, dry landscapes that contain this type of soil.

Spotted Ground Squirrel (Xerospermophilus spilosoma) - University of New Mexico Campus Las Cruces, NM

The Round-tailed Ground Squirrel (Xerospermophilus tereticaudus), known as "Ardillón cola redonda" in Spanish, live in the desert of the Southwestern United States and Northwestern Mexico. They are called "ground squirrels" because they burrow in loose soil, often under mesquite trees and creosote bushes.

Ground squirrels are well-adapted to desert 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, but do not hibernate. 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.[6] 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.

Round-tailed Ground Squirrel (Xerospermophilus tereticaudus) - Casa Grande National Monument picnic grounds