Geographic Range
Dark kangaroo mice,
Microdipodops megacephalus
, are found only in the Neartic region, specifically the Great Basin Desert of western
North America. The native range of dark kangaroo mice extends longitudinally from
the easternmost part of northern California, through the majority of Nevada, to parts
of western-central Utah. Latitudinally, dark kangaroo mice range from parts of central
Oregon south to mid-southern Nevada.
Habitat
Dark kangaroo mice inhabit dry desert areas where there is an abundance of loose sand
and gravel. Because they inhabit the Great Basin, sand dunes and other ridges provide
adequate shelter and temperature for dark kangaroo mice. They create an underground
system throughout sand dunes that provide protection from predators and extreme temperatures.
Typical elevation ranges from 1200 to 2050 m.
- Habitat Regions
- temperate
- terrestrial
- Terrestrial Biomes
- desert or dune
Physical Description
Dark kangaroo mice are named for their dark brown and black fur color and elongated hind legs. Their average adult weight is 13.5g (range 10 to 17g), and average total length is 158.5 mm (range 140 to 177 mm). Their average tail length is 84 mm (range 68 to 103) and average hind foot length is 25 mm. Sexes are alike in relative size and weight. Because the ears and head are large, similar in profile to the body is similar, their appearance is like one round shape.
The dark brown and black fur color distinguishes dark kangaroo mice from the closely-related
species,
Microdipodops pallidus
(pale kangaroo mouse), which has a lighter, pale brown fur color. Because dark kangaroo
mice hibernate in the harsh winter, no geographic or seasonal variation in pelage
or mass has been reported.
- Other Physical Features
- endothermic
- homoiothermic
- bilateral symmetry
- Sexual Dimorphism
- sexes alike
Reproduction
There is little information known about the specifics of the dark kangaroo mice mating
systems. After the winter hibernation months, dark kangaroo mice begin the breeding
season. This species is promiscuous, with multiple males mating with multiple females.
- Mating System
- polygynandrous (promiscuous)
Pregnant female dark kangaroo mice have been observed throughout the month of March
extending through the month of October. For this reason, these mice are thought to
have multiple litters per season. Gestation periods have been measured at 24.5 days
(range 22 to 27). Most juvenile captures have been in May and June, but presumably
they could be found later into the summer and fall months. Litter sizes are known
to average 3.9 (range 2 to 7). Additional information about the general behavior of
reproduction is unknown.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- viviparous
The parental investment of the dark kangaroo mouse remains unknown other than the
mother nurses and protects the young until they can survive on their own.
- Parental Investment
- female parental care
-
pre-fertilization
- provisioning
-
protecting
- female
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
protecting
- female
-
provisioning
Lifespan/Longevity
The only information known about the lifespan of dark kangaroo mice is the average
years the species survives in the wild and in captivity. On average, the lifespan
in both captivity and the wild is 5.4 years.
Behavior
Dark kangaroo mice are solitary, living mainly independently from others of their species. They live in underground burrows due to the species' sensitivity to sunlight as well as moonlight. They emerge from these burrows during two hours following the sunset. The main form of movement is bipedally - hopping with their large hind legs.
Foraging behavior of dark kangaroo mice consists of scratch-digging. Scratch-digging is used when there are seeds mixed into the soil that the mice need for food. The seeds from the soil are collected and stuffed into the external cheek pouches of the dark kangaroo mice to be used as a food source during the winter. Dark kangaroo mice exhibit a food-hoarding behavior, only sharing food with dependent young. They are nocturnal, with activity affected by rain, moonlight, and relative humidity.
These mice are through to hibernate but no concrete evidence has been presented.
- Key Behaviors
- fossorial
- saltatorial
- motile
- sedentary
- hibernation
- solitary
Home Range
Individual home ranges of dark kangaroo mice may overlap, and individuals will actively
defend their burrow. Although their home ranges can change seasonally, the annual
average home range was 6613 square meters for males and 3932 square meters for females.
Communication and Perception
Dark kangaroo mice communicate strictly using tactile and chemical means. They perceive
the environment using the same means of touch and smell. No record has been made of
information concerning the communication between potential mates nor on any notable
form of specific communication within the species.
Food Habits
Dark kangaroo mice use external cheek pouches to carry food. Because they are granivores,
the main food source are small seeds from the shrubs and vegetation in the Sagebrush
Scrub zone of the Great Basin. In summer months, these mice are thought to consume
insects, as well. They don’t drink water, but instead meet all of their water needs
through metabolic breakdown of the seeds they consume.
- Animal Foods
- insects
- Plant Foods
- seeds, grains, and nuts
- Foraging Behavior
- stores or caches food
Predation
Anti-predator adaptations found in dark kangaroo mice include the complex burrow underground
as well as a high-pitched squeal they emit when threatened. They are also cryptically
colored to minimize detection by predators. Known predators of this species include
foxes (
Vulpes
species in this range), rattlesnakes in the genus
Crotalus
, owls, and badgers (
Taxidea taxus
) native to the Great Basin Desert.
- Anti-predator Adaptations
- cryptic
Ecosystem Roles
Dark kangaroo mice are prey to mammalian and avian predators foxes and owls This species does not act as predators in their ecosystem. Their burrows serve to function in soil aeration.
These mice are host to ticks (
Dermacentor parumapertus
) and mites (
Ischyropoda furmani
).
- Ecosystem Impact
- soil aeration
- ticks Dermacentor parumapertus
- mites Ischyropoda furmani
Economic Importance for Humans: Positive
Dark kangaroo mice provide detailed information about water conservation when studied
in laboratories. The information gathered from these studies can be used to benefit
human water conservation tactics.
- Positive Impacts
- research and education
Economic Importance for Humans: Negative
There are no known adverse effects of dark kangaroo mice on humans.
Conservation Status
Dark kangaroo mice are a species of "Least Concern" on the IUCN Red List, although
their population is believed to be declining. They have no special status on US Federal
List, State of Michigan list, or CITES. The introduction of non-native grasses has
apparently negatively affected some populations. Habitat alterations, including the
alteration of natural lands to agricultural fields, combined with habitat fragmentation
may also be having a marked impact on these mice. There are no known conservation
efforts in place for this species.
Additional Links
Contributors
Emily Amos (author), Radford University, Alex Atwood (editor), Radford University, Karen Powers (editor), Radford University, Joshua Turner (editor), Radford University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
- Nearctic
-
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- temperate
-
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
- terrestrial
-
Living on the ground.
- desert or dunes
-
in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.
- endothermic
-
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- polygynandrous
-
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- iteroparous
-
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- viviparous
-
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- female parental care
-
parental care is carried out by females
- fossorial
-
Referring to a burrowing life-style or behavior, specialized for digging or burrowing.
- saltatorial
-
specialized for leaping or bounding locomotion; jumps or hops.
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- hibernation
-
the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.
- solitary
-
lives alone
- tactile
-
uses touch to communicate
- chemical
-
uses smells or other chemicals to communicate
- stores or caches food
-
places a food item in a special place to be eaten later. Also called "hoarding"
- cryptic
-
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
- soil aeration
-
digs and breaks up soil so air and water can get in
- herbivore
-
An animal that eats mainly plants or parts of plants.
- granivore
-
an animal that mainly eats seeds
- tactile
-
uses touch to communicate
- chemical
-
uses smells or other chemicals to communicate
References
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