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Heermann's kangaroo rat

Heermann's kangaroo rat is a species of kangaroo rat, a rodent in the family Heteromyidae. Their long smooth pelage resembles typical kangaroo rats, with their dorsal side showing a mixed range of olive, black and orange colors. Nine different sub-species of Dipodomys heermanni have been proposed.

Distribution
Dipodomys heermanni is endemic to California in the United States. Even with this small home range, the Heermann's kangaroo rat is listed as a species of least concern according to the IUCN. According to USFWS the sub-species D.h. morroensis is listed as endangered. == Habitat and population ==
Habitat and population
With all the interconnected surface runways within a community composed of individual Heermann's kangaroo rats, it is incredibly difficult to narrow down individual home ranges. Because of this difficulty in distinguishing home ranges, the estimated values fluctuate greatly. Population densities experience many ups and downs and have been shown to range between . There seems to be no way of predicting whether or not emigration has anything to do with these large fluctuations in population density. Typically, it is only the larger rats that take part in emigration, and females have been shown to exhibit this behavior more often than males. == Ecology and behavior ==
Ecology and behavior
Ecology Heermann's kangaroo rats are burrowing animals, and they manipulate the tunnels already made by other burrowing animals to make their own, such as tunnels made by ground squirrels (Spermophilus). The extent of the burrowing behavior depends on the type of soil present: in areas with fine deep soil their tunnels average long and up to beneath the surface, whereas in shallow rocky soils the average length is and they do not extend deeper than . Heermann's kangaroo rats are granivores, and seeds provide a significant nutritional value to their diet. They are also herbivores, especially during seasons of winter and spring. Additionally, in the wild they have been documented capturing insects at night such as moths, beetles, and grasshoppers. Most of the plant material near the burrows in their home ranges are utilized. They achieve necessary water consumption from seeds and dew from the plant material in their diet, and will only drink from a puddle or direct water source if water intake isn't achieved for several weeks. If the dry food matter increases and humidity is decreased, the mean daily activity of the rats drastically declines. High rates of interspecies competition has been observed; however, intraspecies competition between Heermann's kangaroo rats has not been directly observed. They have been observed dust-bathing after foraging. This behavior consists of them lying on their bellies with they hind limbs extended or alternating keeping either their fore or hind limbs straight. It is thought to help withdraw oil and moisture, thus keeping their fur dry and sleek. Traveling is mostly done in a bipedal position with occasional hops that generally reach distances about . When moving slowly they are usually in a plantigrade position. On the other hand, when they are moving more quickly they can become saltatorial and can even become ricochetal. When running rapidly their hops can range from , and their tail aids in providing counterbalance. == Reproduction ==
Reproduction
Heermann's kangaroo rat has a wide window in which it primarily breeds, ranging from February to October. Its highest breeding activity is in April, and this decreases in July. Heermann's kangaroo rat rarely show increased levels of sexual behavior. Copulation is rather quick, and typically only lasts a couple seconds. If the animals are caged, the rats show no increase in sexual behavior. Females rats will even show aggression if her genitalia are swollen and enlarged. During labor, the female rat will assist the delivery of the young with her front paws. The female Heermann's kangaroo rats also fondle her babies after birth with fondling, smelling, and licking. The young are born bright pink, wrinkled, hairless (except for colorless vibrissae), poikilothermic, and with their eyes closed. Within 22 hours of birth, hair is already developing and beginning to obtain adult pigmentation, beginning at the head and eventually reaching the feet by day 7. Before day 9 it is not possible to differentiate sexes because external genitalia appear the same. Weaning is completed around day 25, and young begin hunting and scavenging independently by 4 weeks. == Proposed sub-species ==
Proposed sub-species
Nine different sub-species of Dipodomys heermanni had been proposed: • Dipodomys heermanni arenaeDipodomys heermanni berkeleyensis (Berkeley kangaroo rat)Dipodomys heermanni dixoni (Merced kangaroo rat) • Dipodomys heermanni goldmaniDipodomys heermanni heermanni (Heermann's kangaroo rat) • Dipodomys heermanni jolonensisDipodomys heermanni morroensis, (Morro Bay kangaroo rat) • Dipodomys heermanni swarthiDipodomys heermanni tularensis However, recent mitochondrial DNA and morphometric analyses failed to show support for any genetic differentiation or morphological clustering across geography to support the above subspecies delineations. ==References==
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