Desert kangaroo rats do not generally eat succulent plants. They prefer a diet of dried plant matter from the previous year, particularly leaves of sage, and seeds of the creosote bush and will also eat seeds. D. deserti will drink water when it is available, but can survive long periods of time without water, subsisting on their dry diet (Best et al., 1989).
Plant Foods: leaves; seeds, grains, and nuts
Foraging Behavior: stores or caches food
Primary Diet: herbivore (Folivore )
Desert kangaroo rats serve as prey to snakes, hawks, owls, bobcats, spotted skunks, coyotes and foxes (Best, 1999).
Known Predators:
All of the members of the genus Dipodomys have fur-lined cheek pouches that are used to transport seeds. D. deserti has four toes on each hind foot, and all of the feet are covered with long hairs. The upper parts of the body are pale brown to grayish (depending on the subspecies), and the underside is white. D. deserti has indistinct white spots over the eyes, behind the ears (which extends across the shoulder to the white underbelly), and an indistinct white band across the hips. There is also a darker spot of pelage at the base of facial vibrissae (Best, 1999).
Males average 342 mm in length and females average 331 mm in total length. The tail is usually 201 mm long in males and 195 mm in females, which accounts for more than ½ of the total length. In both sexes, the tail has long, white-tipped guard hairs along the top. D deserti has the thickest hair in their genus. Juvenile pelage resembles that of the adult, but is typically shorter and less dense.
Desert kangaroo rats are one of the most sexually dimorphic species of kangaroo rats, with males being about 2.5% larger than females. Males weigh between 91 and 148 g, whereas females weigh from 83 to 141 g
D. deserti posses huge auditory bullae (which frequently meet in the center of the dorsal surface of the skull, completely hiding the interparietal and supraoccipital bones). The tooth enamel is thick. The sides of the teeth lack grooves, and they have flatter skulls than any other member of the genus Dipodomys.
Populations do not exhibit much geographic variation, possibly because D. deserti inhabit a region that has relatively homogenous terrain and no permanent geographic barriers separating populations (Best 1989).
Range mass: 83 to 148 g.
Range length: 331 to 342 mm.
Sexual Dimorphism: male larger
Other Physical Features: endothermic ; bilateral symmetry
Average basal metabolic rate: 0.517 W.
Although little has been reported on the longevity of wild D. deserti, lifespan in captive individuals has ranged between 5.5 years to 8 years (Brattsrom, 1959; Nader, 1979)
Typical lifespan
Status: captivity: 5.5 to 8 years.
Dipodomys deserti is adapted to live in the lowest, hottest, and most arid regions of North America (Nader, 1978). D. deserti is associated with areas that have substantial accumulations of wind driven sand. The number of sand dunes may limit the distribution of D. deserti, but they may be present in arid regions that have silty ground and are also known to occur at one locality in central Arizona where the soil is gravelly (Best et al., 1989).
In contrast to larger members of the genus, desert kangaroo rats occur in areas that receive little precipitation. To compensate for the extreme and prolonged aridity of the region, they are restricted to sand dunes, which harbor richer food sources.
D. deserti uses mainly un-vegetated mounds for burrow sites. Burrows are typically made in areas which are not highly ephemeral. On the surface, the burrow is lumpy, uneven and has many sloping entrances that lead down into the maze of passages. Some of these may be plugged with dirt. Underground chambers consist of multiple storerooms and a central nest. Within these chambers, D. deserti stores large amounts of mesquite pods and other plant seeds.
Desert kangaroo rats may form widely spaced colonies with clusters of 6-12 large burrows in each colony. However, these colonies rarely last for long periods of time and will be moved when food is scarce (Best et al., 1989).
Range elevation: -60 to 1,710 m.
Habitat Regions: terrestrial
Terrestrial Biomes: desert or dune
Other Habitat Features: agricultural
Desert kangaroo rats inhabit dunes in the most arid regions of southwestern North America. They occur at elevations ranging from 60 meters below sea level in Death Valley, California, to 1,710 meters in Huntoon Valley, Nevada (Best et al., 1989).
Biogeographic Regions: nearctic (Native )
Although the ecosystem roles of this species have not specifically be reported, they are prey to a large number of carnivores, and so the availability of these rodents is likely to affect predator populations. Also, through their seed caching behavior, they disperse seeds.
Ecosystem Impact: disperses seeds
There are no reported positive effects of this species on humans.
There are no reported negative effects of this species on humans.
This species has no special conservation status, but has been reported to suffer from automobile traffic. However, there is a positive impact on this species from agriculture, which may outweigh the negative effect of auto traffic.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
Perception Channels: tactile ; chemical
Although D. deserti is not a species at risk, some interactions with humans can be detrimental. Vehicles on southeastern California highways are reported to have severely impacted populations of desert kangaroo rats, resulting in near elimination of the species along a wide area on both sides of the road (Best et al., 1989).
Conversely, it appears that cultivation favorably alters the habitat for desert kangaroo rats. Cultivation removes vegetative cover, allowing the winds to pile up large quantities of sand and form dunes. Although desert kangaroo rats won’t inhabit areas under immediate cultivation, they quickly colonize a region once farming has ceased.
Dipodomys is a member of one of the most diverse Hetromyid subfamilies, the Dipodomyinae, which contains 9 genera, more than 60 species and has a rich fossil history dating back 20 million years (Carrasco, 2000). However, no fossils of D. deserti have been discovered. Most likely, D. deserti originated in the early part of the Pleistocene in southeastern regions of California and the lower Colorado desert (Nader, 1978).
The mating system has not been reported. However, that the males are larger than the females suggests competition between males for mating. This type of male-male competition is usually associated with some males obtaining matings with more females than other males do. Copulatory plugs are formed after mating, and these are typically a form of post-copulatory competition between males. This suggests that females are likely to mate with multiple males. It seems likely, therefore, that the mating system is polygynadrous.
Mating System: polygynandrous (promiscuous)
D. deserti show no definitive courtship period because of their intense aggressive behavior. However, there is a brief precopulatory period when the male and female halt their aggressive behavior. Reproductive activity begins early in January and continues through early July. Adult females will come into estrus 10-15 days post-partum and accept mating attempts by males. (Best et al., 1989) Females who have mated already typically resist further advances by males. A few hours after copulation, a copulatory plug forms in the vaginal orifice. This persists for several days, preventing or inhibiting further mating.
The gestation period ranges from 29-32 days and the number of embryos ranges from 1-6. One or two litters are produced annually. Young are born headfirst and the mother assists delivery by pulling on the fetal membrane. After parturition, the mother will kick sand on the neonates, perhaps to dry them. (Best, 1999).
Sexual maturity probably occurs around 2 months of age, as is common for other species of Dipodomys.
Breeding season: Reproduction begins in January, and ends in early July.
Range number of offspring: 1 to 6.
Range gestation period: 29 to 32 days.
Average weaning age: 21 days.
Average age at sexual or reproductive maturity (female): 2 months.
Average age at sexual or reproductive maturity (male): 2 months.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); viviparous
Average birth mass: 3.04 g.
Average number of offspring: 3.
The mass of D. deserti at birth ranges between 2.2 and 4.6 g. The neonate is approximately 52 mm in length, and is naked, with thin, pink, transparent skin. Complete pigmentation and furring appear by weaning, around 21 days of age (Best, 1999). Females nurse their young in the nest . Immediately after they are born, a female kicks sand onto her offspring. This may help to dry them off.
Parental Investment: altricial ; female parental care
The desert kangaroo rat (Dipodomys deserti) is a rodent species in the family Heteromyidae that is found in desert areas of southwestern North America.[2] It is one of the large kangaroo rats, with a total length greater than 12 inches (300 mm) and a mass greater than 3.2 ounces (91 g).[3]
The desert kangaroo rat is found in arid parts of southwestern North America, including Death Valley, the Great Basin, the Mojave Desert, and portions of the Sonoran Desert.[4] Though kangaroo rats persist in a variety of soils,[5] desert kangaroo rats live exclusively in areas with loose sand, often dune terrain.[6] The places on this list constitute some of the most extreme deserts in the United States including Death Valley, which has the record for the hottest place on the continent.[7]
Desert kangaroo rats are denizens of desert areas with sandy soil; vegetation is typically sparse and consists of creosote bush, a variety of grasses, and cacti.[8] Desert kangaroo rats live in burrow systems under slight mounds of soil 6-9m across;[8] they sleep in a den, which is sealed off at extreme temperatures, during the day.[4] Groups of 6-12 widely spaced burrows may constitute a colony of this species, which is otherwise solitary.
Seeds are the dominant component of the diet of desert kangaroo rats. The size of the seeds consumed by the species tends to be larger than seeds consumed by other, sympatric heteromyids.[8] When presented with patches with variation in seed sizes and densities—which in combination vary total profitability—desert kangaroo rats tend to choose large-seed patches but reduce profitability of a set of patches to similar levels.[9] Seed selection also appears correlated with nutritional content, with this species choosing seeds with high carbohydrate content.[10] Although some kangaroo rats will consume green vegetation, desert kangaroo rats do not.[8] Feeding occurs in fits and starts of movement and at relatively discrete locations, with an average distance of ~7 m (22 ft.) between stops.[8]
Most kangaroo rat species live in arid environments and are known for their ability to make use of metabolic water rather than requiring it from the environment. While the desert kangaroo rats do consume available water,[8] the vast majority of their water requirements are met from byproducts of metabolic processes. Adaptation to very low quantities of water (free or metabolic) is highlighted by the very long water turnover [11] times for the species, on the order of 2–3 weeks.[12]
Kangaroo rats achieve the ability to be sustained on limited water by having incredibly derived kidneys. To remove waste without losing water, many species have developed mechanisms to concentrate their urine. This happens in the kidneys.[13] There seems to be an inverse correlation of body mass to ability to concentrate urine.[14] So naturally small rodents can persist in much more water deficient environments than larger animals. The desert kangaroo rat has a kidney structure very similar to those of other rodents, but it has much longer papilla (mammalian species). Papilla lengths, along with number of nephrons, play a crucial role in urine concentration.[13]
Desert kangaroo rats have the longest nasal cavity of all the kangaroo rats, which allows for better water conservation. Hot, dry air can remove water from the body. The long nasal cavities reduce this water loss by cooling the air leaving the lungs. Cooling air releases moisture for reabsorption to the body so its loss can be avoided in a situation where water is a precious resource.[5]
Kangaroo rats drum their feet. Many different species of kangaroo rats' drumming pattern have been previously studied. They are thought to have evolved independently. Some use drumming to communicate location and other kangaroo rats respond in kind. This is not the case with the desert kangaroo rat.[15] The desert kangaroo rat, living in a sand dune environment, has the highest level of food scarcity. When the desert kangaroo rat hears a drum from another rat, it comes out of its burrow and chases it away or engages in a rollover fight.[16]
Desert kangaroo rats function under a high risk of predation for a variety of reasons. The first of which is they forage alone. They do not have a community of other rats to watch out for snakes or other predators. Secondly, in the desert, food is scarce and spread out, so desert rodents have to spend a substantial amount of time out of their holes searching for food. Because of these reasons, the desert kangaroo rat has had to evolve a few adaptations to protect itself.[16]
Though the more commonly studied Merriam's kangaroo rat protects itself by predator avoidance, the desert kangaroo rat behaves more aggressively.[16] In the case of a snake, the desert kangaroo rat drums its feet and moves within striking distance of the snake and kicks sand in the air. Though this is an incredibly dangerous activity for a small rodent, it does these things to let the snake know it is alert to its presence.[17] Snakes are less likely to attack a rodent if the prey knows the snake is there. Desert kangaroo rats exclusively kick sand due to their natural environment being characterized by loose sand dunes.[16] The desert kangaroo rat also uses its hind limbs to kick away attacking snakes in order to avoid being injected with venom.[18]
{{cite journal}}: CS1 maint: multiple names: authors list (link) The desert kangaroo rat (Dipodomys deserti) is a rodent species in the family Heteromyidae that is found in desert areas of southwestern North America. It is one of the large kangaroo rats, with a total length greater than 12 inches (300 mm) and a mass greater than 3.2 ounces (91 g).
