Pale kangaroo mouse (Microdipodops pallidus)

Also known as: Soda Spring Valley kangaroo mouse
KingdomAnimalia
PhylumChordata
ClassMammalia
OrderRodentia
FamilyHeteromyidae
GenusMicrodipodops (1)
SizeTotal length: 15 - 16.9 cm (2)
Tail length: 7.4 - 9.4 cm (2)
Hind foot length: 2.5 - 2.7 cm (2)
Weight10 - 17 g (3) (4)
Top facts

The pale kangaroo mouse is classified as Least Concern (LC) on the IUCN Red List (1).

Named for its pale-furred back and long hind limbs and feet, the pale kangaroo mouse (Microdipodops pallidus) is a large-headed rodent (4) (5) with fur-lined external cheek pouches (2) (4). This species is bipedal, meaning that it generally moves around on its strong hind legs, hopping much like a kangaroo (4) (5).

The soles of the pale kangaroo mouse’s large hind feet are densely furred (2) (4) (5), and each foot is fringed with stiff hairs (4) (5). This increases the surface area of the foot, which prevents this rodent from sinking into the sand (5).

The fur of the pale kangaroo mouse is soft, silky (4) (5) (6), and long (4) (5). The upperparts are creamy or light buff (2) (4) (5), while the underparts are pure white (3) (4) (5) (6). White patches of fur can also be seen behind the ears (2), as well as at the base of the whiskers and above the eyes (4).

As in the similar dark kangaroo mouse (Microdipodops megacephalus), the tail of the pale kangaroo mouse is thickest in the middle (2) (6) (7). However, unlike its close relative, the pale kangaroo mouse has a creamy-buff tail (4), which does not have a dark tip (3) (6).

There are currently five recognised subspecies of the pale kangaroo mouse, one of which is thought to be under threat (8).

The pale kangaroo mouse is endemic to the United States (9), and its patchy distribution encompasses parts of south-western Nevada and south-eastern California (6), comprising several disjunct areas (1).

The pale kangaroo mouse is found at elevations between 1,200 and 1,750 metres (1) (6), although in California the range is generally narrower, from 1,530 to 1,590 metres above sea level (1).

The pale kangaroo mouse prefers lowland areas (1) (2) (10), and is generally found in dry, desert habitats (6) (8), particularly those with fine, sandy substrates (1) (2) (3) (6). Pale kangaroo mouse habitat often borders dried-out, alkaline lakes (1) (8), and this hopping rodent species is also found on sand dunes and in areas with gravelly soils (6).

In terms of vegetation, scrub species tend to dominate the pale kangaroo mouse’s habitat, including shadscale (Atriplex confertifolia) and sagebrush (Artemisia tridentata) (1).

The pale kangaroo mouse is strictly nocturnal (1) (4) (5), only venturing out during the cooler desert nights, and it is extremely sensitive to light (5). A noticeable burst of activity occurs just after sundown (1) (6), and throughout the night the pale kangaroo mouse forages for food away from shrub cover (4) (6). This rodent species moves about its habitat in leaps and bounds, using its strong hind limbs to propel it forwards and its tail for balance (4) (5).

The diet of the pale kangaroo mouse consists mainly of seeds (1) (3) (4) (5) (6), but it also eats a variety of insects (1) (4) (5) (6), particularly during the summer months (5). Seeds collected during a foraging outing are carried back to the burrow in the pale kangaroo mouse’s external cheek pouches (4), and then stored in a cache within the burrow (1).  

Interestingly, the pale kangaroo mouse also stores food as body fat within the bulge in the centre of its tail, a unique feature among small mammals native to North America (4). This fat deposit enlarges during the summer and is then used as an energy source during the colder months (4) (5). Amazingly, the pale kangaroo mouse does not need to drink water to survive. Instead, it obtains the moisture it requires from its food (4) (5), and conserves water by producing concentrated urine and dry faeces (4).

The pale kangaroo mouse lives in a simple burrow (4) (5), which it excavates in soft, wind-blown sand (1). The entrance is usually located near a shrub (4) (5). It is in this burrow that the young are born, with breeding occurring throughout the summer (4). Between two and seven young are born per litter (1) (4) (5) (6), and the female pale kangaroo mouse can produce more than one litter per breeding season (3) (4) (5) (6).

The hibernation patterns of the pale kangaroo mouse are not fully understood. Its close relative the dark kangaroo mouse is known to hibernate from November to March during the harsh, cold winter (4), but the pale kangaroo mouse may only hibernate for a few days at a time (1).

Although the pale kangaroo mouse is not currently considered to be at risk of extinction, it is known to be suffering a population decrease (1).

The introduction of weedy grasses, along with extreme habitat alteration for the purpose of cultivation, has caused a decline in some populations of the pale kangaroo mouse. As well as these human-related habitat changes, natural shifts in the types of vegetation present have resulted in the pale kangaroo mouse being displaced by other rodent species (1) (8). These effects may be amplified by the fact that the distribution of the pale kangaroo mouse is already somewhat fragmented (1), with the patchy and isolated distribution of the most threatened subspecies leaving it particularly vulnerable to habitat alteration (8).

The pale kangaroo mouse is not currently considered to be at risk of extinction, and is not known to occur in any protected areas (1) (8).

Proposed conservation action for the pale kangaroo mouse includes the initiation of a survey and monitoring programme to investigate the human-induced and natural alterations that are affecting the distribution of this species. Further surveys to determine the pale kangaroo mouse’s population status and distribution limits have also been suggested (8).

More information on the conservation of the pale kangaroo mouse and other North American rodents:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

  1. IUCN Red List (July, 2012)
    http://www.iucnredlist.org/
  2. Ingles, L.G. (1947) Mammals of California. Stanford University Press, California.
  3. Jameson, E.W. and Peeters, H.J. (2004) Mammals of California. University of California Press, California.
  4. Rafferty, J.P. (2011) Rats, Bats and Xenarthrans. The Rosen Publishing Group, New York.
  5. Nowak, R.M. (1999) Walker’s Mammals of the World. Johns Hopkins University Press, Baltimore.
  6. Reid, F. (2006) A Field Guide to Mammals of North America, North of Mexico. Houghton Mifflin Harcourt, Boston.
  7. Verts, B.J. and Carraway, L.N. (1998) Land Mammals of Oregon. University of California Press, California.
  8. Hafner, D.J. (1998) North American Rodents: Status Survey and Conservation Action Plan. IUCN/SSC Rodent Specialist Group, IUCN, Gland, Switzerland, and Cambridge, UK. Available at:
    http://data.iucn.org/dbtw-wpd/edocs/1998-039.pdf
  9. MobileReference (2008) The Illustrated Encyclopedia of North American Mammals: A Comprehensive Guide to Mammals of North America. MobileReference, Boston.
  10. Bowers, N., Bowers, R. and Kaufman, K. (2007) Kaufman Field Guide to Mammals of North America. Houghton Mifflin Harcourt, Boston.