Ammospermophilus harrisii (Audubon & Bachman, 1854)

Taxonomy and Etymology

Ammospermophilus harrisii, first described by Audubon & Bachman in 1854, is named after Edward Harris.

Fur Markings

Individuals of this species have distinctive markings on their grey fur, with brown highlights on the sides and legs, a white stripe running down the side of the torso, and a white ring encircling the eyes.

Seasonal Fur Variation

Their fur is longer in winter than in summer.

Adult Size and Weight

Adult A. harrisii weigh around 4–5 ounces (110–140 g), and measure 8.5–10 inches (22–25 cm) excluding the tail, which measures 3–4 inches (7.6–10.2 cm).

Visual Similarity to Other Species

They can be mistaken for chipmunks.

Body Temperature Range

This species has a high body temperature ranging from 97 to 107 degrees Fahrenheit (36.7 to 41.6 °C).

Tail Shade Behavior

To protect itself from the heat of the Sonoran Desert, A. harrisii holds its tail over its body to provide shade.

Heat Dumping Behavior

It also uses a heat reduction method called "heat dumping", where individuals move to shaded spots and lie spread-eagled against the ground.

Activity and Thermoregulation

They are active during the day, do not sweat, and reduce their body temperature by salivating.

Mating Period

The optimal reproductive period for A. harrisii falls between February and March, though mating can occur any time between December and June.

Gestation and Litter Details

Gestation lasts thirty days, and females usually produce one litter per year with an average of 6.5 pups.

Juvenile Development

Newborns reach adult size around 217 days after birth, and both males and females reach sexual maturity within their first year.

US Distribution

The habitat of A. harrisii spans the Southwestern United States, specifically Arizona and southwestern New Mexico.

Mexican Distribution

Its range extends outside the US into northwestern Sonora, Mexico.

Arizona Conservation Designation

The Arizona Game and Fish Department designates A. harrisii as a non-game animal.

Habitat Threats

While the species is not endangered, the size of its habitat range is being reduced by human development.

Herbivorous Diet Components

Its diet includes the fruit and seeds of local cactus plants, and mesquite beans.

Omnivorous Diet Components

It is not exclusively herbivorous, and also consumes insects, small rodents, and carrion.

Predators

Its predators include bobcats, coyotes, local snakes, and domestic animals such as dogs and cats.