Dipodomys ordii Woodhouse, 1853

Species Introduction

Ord's kangaroo rat (Dipodomys ordii) is a species of kangaroo rat native to western North America.

Native Range

Its native range covers the Great Plains and the Great Basin, extending from extreme southern Canada to central Mexico.

Hind Foot Distinguishing Trait

This species has a fifth toe on its hind feet, a trait that distinguishes it from Dipodomys elator.

Body Coloration

It is bicolored, with gold-brown hair along its dorsal side and a white underbelly.

Tail Morphology

It has a long tail with a bushy tip; the tail is dark on both its dorsal and ventral sides, with a white lateral stripe running along it.

Body and Hind Foot Size

Its hind feet are modified for jumping, measure over 35 mm in length, and the species' total body length exceeds 240 mm.

Tail Length Distinguishing Trait

Its tail is typically less than 160 mm long, another feature that distinguishes it from D. elator, which has a tail longer than 160 mm.

Conservation Status

While Ord's kangaroo rat is a common species throughout the United States, the Canadian population of the species is classified as endangered.

Full Geographic Range

The full range of Ord's kangaroo rat extends from southern Alberta and southern Saskatchewan in Canada south to southern Hidalgo, Mexico, and from central Oregon and eastern California in the west east to central Kansas and Oklahoma.

General Habitat Type

Ord's kangaroo rats mostly inhabit semiarid, open habitats.

Nevada Habitat

In Nevada, they have been trapped in desert scrub with gravelly soil, flat pebble desert, and washes.

Utah Habitat

In Utah, they favor open shrublands and grasslands growing on sandy soils.

Idaho Habitat

In the big sagebrush/crested wheatgrass (Agropyron cristatum) range of southeastern Idaho, most Ord's kangaroo rat captures occurred on disturbed sites or areas with sparse vegetation cover: sites dominated by Russian thistle (Salsola kali), cheatgrass (Bromus tectorum), and green rabbitbrush (Chrysothamnus viscidiflorus) had the most captures, followed by disturbed areas seeded to crested wheatgrass, then undisturbed big sagebrush.

South Dakota Habitat

In western South Dakota, the species is associated with black-tailed prairie dog (Cynomys ludovicianus) towns.

Wyoming Habitat

In Wyoming, Ord's kangaroo rats are abundant in sand dune communities where vegetation grows taller than 25 cm (10 inches) and bare ground makes up more than 40% of the area.

Colorado Habitat

In Colorado, the species was captured primarily in open areas with firm soil.

Burrow Soil Requirements

Ord's kangaroo rats need firm or lightly compacted soil to build their burrows; highly compacted soils are too hard for them to dig.

Texas Habitat Restrictions

In areas of desert pavement or tough clay soils in the Trans-Pecos region of Texas, the species is restricted to pockets of windblown sand and alluvial soils along arroyos.

Interspecific and Intraspecific Competition

Among Dipodomys species, Ord's kangaroo rats experience strong intraspecific competition and little interspecific competition.

New Mexico Sympatric Microhabitat Partitioning

In New Mexico, where Ord's kangaroo rats live in sympatry with Merriam's kangaroo rats (D. merriamii), Ord's kangaroo rats were mostly captured in grassy microhabitats, while Merriam's kangaroo rats were captured more often in areas around creosotebush.

Habitat Modification Population Shift

When herbicide defoliation of shrubs (done to improve rangeland) reduced the live canopy cover of creosotebush, it led to an increase in bush muhly (Muhlenbergia porteri). After this treatment, Ord's kangaroo rats replaced Merriam's kangaroo rats as the dominant rodent species. This shift is thought to be caused by the change in habitat structure to open grass.

Removal Experiment Results

Removal experiments designed to establish single-species populations of kangaroo rats were unsuccessful, because many kangaroo rats are transient and quickly occupy any vacated habitats.

Burrow Occupancy

Only one adult Ord's kangaroo rat occupies a given burrow system, except for a brief period during breeding activity.

Territorial Behavior

Little territorial behavior occurs above ground, except near burrow entrances, which are defended.

New Mexico Home Range Size

In New Mexico, the annual home ranges of Ord's kangaroo rats in mesquite habitat averaged 1.36 hectares (3.35 acres).

Nevada Home Range Size

In Nevada sagebrush/grassland, Ord's kangaroo rat home ranges were estimated at 0.62 hectares (1.53 acres) via the circular method and 0.43 hectares (1.06 acres) via the principal component method.

Home Range Movement Patterns

Home range movements increase through spring, and again in late fall and early winter.

Sex-Based Home Range Differences

No significant difference was found between the home ranges of male and female Ord's kangaroo rats; however, female home ranges decrease in size during reproductive periods.

Arizona Movement Distance Data

Recapture data from Ord's kangaroo rats in Arizona shows that the species does not travel far from its home range; most individuals were recaptured within 50 m (165 ft) of their original capture site.

Lifetime Movement Distance Data

Data on lifetime individual movements shows that most individuals were recaptured within 100 m (330 feet) of their original capture site.

Great Basin Population Density

In the sagebrush habitat of the Great Basin, Ord's kangaroo rats reach an average density of 113 rats per 10 ha.

Salt-Desert Shrubland Population Density

In intermountain salt-desert shrublands, average population density is 28 individuals per 10 ha in shadscale communities and 135 individuals per 10 ha in black greasewood (Sarcobatus vermiculatus) communities.

General Diet Type

Ord's kangaroo rats are primarily granivorous and herbivorous.

General Diet Composition

They eat a wide variety of foods, but most commonly consume the seeds of grasses and forbs, along with green vegetation and dry vegetation. They occasionally eat animal material, mostly arthropods.

Colorado Diet Proportions

In Colorado, seeds made up 74% of the species' diet, forbs 13%, grasses and sedges 5%, arthropods 4%, and fungi and mosses 2%.

Idaho Diet Proportions

In the big sagebrush/crested wheatgrass range of southeastern Idaho, Ord's kangaroo rats consumed foods in the following order of proportion: pollen, arthropods, Asteraceae plant parts, and crested wheatgrass seeds.

Texas Primary Diet Items

A study of Ord's kangaroo rat foods in Texas found that the primary foods consumed included seeds of sand paspalum (Paspalum stramineum), honey mesquite, sand bluestem (Andropogon gerardi var. paucipilus), common ragweed (Ambrosia artemisiifolia), and rose-ring gaillardia (Gaillardia pulchella).

Texas Additional Major Diet Items

In Texas, seeds of creosotebush, gramas (Bouteloua spp.) and dropseeds (Sporobolus spp.) make up the major portion of the species' diet. Seeds of mesquite, Russian-thistle, sunflowers (Helianthus spp.), and sandbur (Cenchrus spp.) are also major dietary items.

Seed Transport and Storage

Harvested seeds are carried in cheek pouches back to burrows, where they are either consumed or cached.

Scatter Caching Behavior

Ord's kangaroo rats also cache seeds in scattered shallow holes; this caching activity sometimes leads to seedling emergence. The rats can easily retrieve seeds buried at this shallow depth. A single Ord's kangaroo rat may create tens to hundreds of caches, each holding tens to hundreds of seeds.

Arid Environment Adaptations

Kangaroo rats are physiologically adapted to live in arid environments.

Water Acquisition Strategy

They obtain most of their required water from seeds and succulent plants. They will drink free water when it is available, but do not appear to require it to survive.