scholarly journals Geographic Races Of The Kangaroo Rat Dipodomys Microps

1939 ◽  
Vol 1 (1) ◽  
Author(s):  
E. Raymond Hall ◽  
Frederick Dale
Keyword(s):  
Kangaroo Rat ◽  
Dipodomys Microps

scholarly journals Chiseling Away at the Dogma of Dietary Specialization in Dipodomys Microps

Diversity ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 92
Author(s):  
Sydney Rae Stephens ◽  
Teri J. Orr ◽  
M. Denise Dearing
Keyword(s):  
C3 Plants ◽  
Past Century ◽  
Dietary Specialization ◽  
Natural Diet ◽  
Carbon And Nitrogen ◽  
The Past ◽  
Kangaroo Rat ◽  
Hair Samples ◽  
Field Notes ◽  
Dipodomys Microps

Dipodomys microps, the chisel-toothed kangaroo rat, is heralded as one of few mammalian herbivores capable of dietary specialization. Throughout its range, the diet of D. microps is thought to consist primarily of Atriplex confertifolia (saltbush), a C4 plant, and sparing amounts of C3 plants. Using stable isotopes of carbon and nitrogen as natural diet tracers, we asked whether D. microps is an obligate specialist on saltbush. We analyzed hair samples of D. microps for isotopes from historic and recent museum specimens (N = 66). A subset of samples (N = 17) from 2017 that were associated with field notes on plant abundances were further evaluated to test how local saltbush abundance affects its inclusion in the diet of D. microps. Overall, we found that the chisel-toothed kangaroo rat facultatively specializes on saltbush and that the degree of specialization has varied over time and space. Moreover, saltbush abundance dictates its inclusion in the diet. Furthermore, roughly a quarter of the diet is comprised of insects, and over the past century, insects have become more prevalent and saltbush less prevalent in the diet. We suggest that environmental factors such as climate change and rangeland expansion have caused D. microps to include more C3 plants and insects.

Cochlear Potentials in the Kangaroo Rat, Dipodomys merriami

1971 ◽  
Vol 44 (2) ◽  
pp. 112-118 ◽  
Author(s):  
Jack Vernon ◽  
Paul Herman ◽  
Ernest Peterson
Keyword(s):  
Dipodomys Merriami ◽  
Kangaroo Rat ◽  
Cochlear Potentials

scholarly journals Body mass-specific Na+-K+-ATPase activity in the medullary thick ascending limb: implications for species-dependent urine concentrating mechanisms

2018 ◽  
Vol 314 (4) ◽  
pp. R563-R573 ◽  
Author(s):  
Mun Aw ◽  
Tamara M. Armstrong ◽  
C. Michele Nawata ◽  
Sarah N. Bodine ◽  
Jeeeun J. Oh ◽  
...  
Keyword(s):  
Protein Expression ◽  
Atpase Activity ◽  
Metabolic Rate ◽  
Body Mass ◽  
Whole Body ◽  
Osmotic Gradient ◽  
Thick Ascending Limb ◽  
Rat Strains ◽  
Kangaroo Rat ◽  
Gene And Protein Expression

In general, the mammalian whole body mass-specific metabolic rate correlates positively with maximal urine concentration (Umax) irrespective of whether or not the species have adapted to arid or mesic habitat. Accordingly, we hypothesized that the thick ascending limb (TAL) of a rodent with markedly higher whole body mass-specific metabolism than rat exhibits a substantially higher TAL metabolic rate as estimated by Na+-K+-ATPase activity and Na+-K+-ATPase α1-gene and protein expression. The kangaroo rat inner stripe of the outer medulla exhibits significantly higher mean Na+-K+-ATPase activity (~70%) compared with two rat strains (Sprague-Dawley and Munich-Wistar), extending prior studies showing rat activity exceeds rabbit. Furthermore, higher expression of Na+-K+-ATPase α1-protein (~4- to 6-fold) and mRNA (~13-fold) and higher TAL mitochondrial volume density (~20%) occur in the kangaroo rat compared with both rat strains. Rat TAL Na+-K+-ATPase α1-protein expression is relatively unaffected by body hydration status or, shown previously, by dietary Na+, arguing against confounding effects from two unavoidably dissimilar diets: grain-based diet without water (kangaroo rat) or grain-based diet with water (rat). We conclude that higher TAL Na+-K+-ATPase activity contributes to relationships between whole body mass-specific metabolic rate and high Umax. More vigorous TAL Na+-K+-ATPase activity in kangaroo rat than rat may contribute to its steeper Na+ and urea axial concentration gradients, adding support to a revised model of the urine concentrating mechanism, which hypothesizes a leading role for vigorous active transport of NaCl, rather than countercurrent multiplication, in generating the outer medullary axial osmotic gradient.

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