Dipodomys compactus
Gulf Coast kangaroo rat

Dipodomys compactus has a limited distribution in the southernmost region of Texas and on the islands in the Gulf of Mexico just off the Texas coast. The islands they inhabit run from the Padre Island region in the North, to the barrier islands of Tamaulipas Mexico in the South. (Baumgardner, 1991)

The habitat of D. compactus remains relatively homogeneous throughout their range. Sandy soils that are disturbed or loose are favored. Along with sandy soils, they have a preference for open, sparsely vegetated dunes. Almost all of these animals are captured on the leeward or sheltered side of the landform they inhabited. It is also noteworthy that very few individuals have been captured in undisturbed brush covered areas. (Baumgardner, 1991)

Dipodomys compactus is of medium size, weighing between 44 and 60 g. Males of the species are larger than females, weighing an average og 53 g compared to the average of 45 g for females. However, males are smaller in cranial comparisons. The total length of these animals is between 203 and 266 mm, with males averaging 228.1 mm and females averaging 227.6 mm. The tail length is between 104 and 135 mm, with males and females both averaging just over 199 mm. (Baumgardner, 1991; Baumgardner, 1999; Davis and Schmidly, 1997)

Pelage coloration varies slightly between individuals. The color can range from a gray phase to a reddish orange tint. The varying color is found underneath the black guard hairs on the back, and more noticeably on the sides. The hairs are short and fairly coarse. All color phases have white cheek patches. (Baumgardner, 1991; Baumgardner, 1999; Davis and Schmidly, 1997)

Dipodomys have lived up to 9.8 years in captivity. However, the average life span in the wild is around 2 years. It is likely that D. compactus compares to other members of the genus. (Eisenburg et al., 1990; Goodwin, 1986)

Little is known about the activity of D. compactus in the wild. One laboratory study showed that most activity was at night, with any daytime activity being short in duration and related to feeding or drinking. It is thought that nocturnal habits can be attributed to both an open habitat with the subsequent risk of predation, as well as increased daytime temperatures. (Eisenburg et al., 1990; Kennedy, 1973)

Locomotion in this genus is by saltation. They can move rapidly by hopping on their hind legs. A single hop may propel an animal more than two meters. Forelegs, which are useless for hopping, are only used when walking very short distances. (Nowak, 1999)

Members of the genus Dipodomys are known to remove oils from their fur by bathing in the dust. Sandbathing may also help to mark territories in some species. (Nowak, 1999)

Kangaroo rats construct elaborate burrow systems, with many chambers and long tunnels. The construction of these burrow systems may be one of the major factors influencing the apparent preference of all members of the genus for well drained, loose soils, as such soils are easier for the animals to excavate. (Nowak, 1999)

Dipodomys species in general are highly solitary, fiercely territorial, and will fight savagely if they encounter conspecifics. Only one adult occupies a burrow system. (Nowak, 1999)

Territories are apparently maintained through aggression and also by foot drumming. Drumming of the hind feet may alert intruders, and thereby avoid an aggressive altercation. Foot drumming may also serve to help males attract females. There are also reports of foot drumming as an alarm response to snakes. (Nowak, 1999)

Home Range

The home range of this species has not been reported. However, for other species in the genus, reports of home ranges just under 0.5 ha are common. It is likely that D. compactus is similar to other members of the genus. (Nowak, 1999)

Research on communication in D. comapctus is not extant. However, it is likely that this species is like other members of the genus. Kangaroo rats are not highly vocal, although they do make sounds. Most communication is through scent cues and foot drumming. Tactile communication occurs between mothers and their young, between mates, and between combatants in territorial aggression. Some visual signals, such as body posture, are probably also used in communication with conspecifics. (Nowak, 1999)

Preferred foods consist of grasses, seeds, annual plants, and shrubs. Insects, fruits, buds, leaves, and stems also make up a part of their diet. Dipodomys have been known to amass up to 50 quarts of seeds and grains in their underground storage chambers. (Davis and Schmidly, 1997; Eisenburg et al., 1990; Goodwin, 1986)

Like other members of the genus, D. compactus does not need to drink water. This is clearly an adaptation to the very dry habitats it occupies. These animals make water metabolically, and obtain some from the moister foods they eat. They conserve water by making really concentrated urine. (Baumgardner, 1991)

As with any North American rodent, common ground dwelling predators include coyotes, foxes, raccoons, and various other carnivores. Rattlesnakes, owls, and hawks also prey on this species. Footdrumming may be a warning signal used when encountering snakes. (Eisenburg et al., 1990; Nowak, 1999)

Gulf Coast kangaroo rats are food for a variety of animals. They also implact the plant community through herbivory and dispersal of seeds. (Baumgardner, 1991; Goodwin, 1986)

Dipodomys compactus has been known to pick seeds from newly planted fields. (Davis and Schmidly, 1997)

There is no evidence that this species produces a postive impact on human economies, although, as food for handsome predators, it may provide some indirect benefit to human populations.

The range of D. compactus is rather small, but the population is healthy and shows no signs of decline. This species is not protected under IUCN, ESA, or CITES as of this time. (Baumgardner, 1991)

Dipodomys compactus is believed to be the most primative of the extant kangaroo rats due to its tooth morphology. Also, many Dipodomys go their entire life without drinking free-standing water. They have developed a way of concentrating their urine more effectively than any other North American mammal. All of their water is metabolic or comes from foods that are ingested. (Baumgardner, 1991; Eisenburg et al., 1990)