Comparative niche utilization by two species of kangaroo rats (Genus <i>Dipodomys</i>)

TitleComparative niche utilization by two species of kangaroo rats (Genus Dipodomys)
Publication TypeThesis
Year of Publication1972
AuthorsGaby R
Number of Pages71
Date Published1972
UniversityNew Mexico State University
CityLas Cruces, New Mexico
Thesis TypePh.D. Dissertationpp
Call Number00079
KeywordsDipodomys,diet, Dipodomys,habitat, Dipodomys,niche utilization, Dipodomys,physiology, dissertation, dissertations, kangaroo rat, SEE <DIPODOMYS, mammal, also SEE <RODENT>, rodent, Dipodomys, rodent, kangaroo rat, Dipodomys, theses, thesis
AbstractAspects of the niche requirements of Dipodomys merriami and Dipodomys ordii in southern New Mexico were compared. The parameters investigated included habitat, diet, microenvironment and comparative physiology.D. merriami inhabited rockier sites than D. ordii, and had burrows that were both shallower and simpler than those of D. ordii. A comparison of burrow microclimate revealed that the burrows of D. ordii were significantly more humid in the summer than were those of D. merriami, and that the maximum temperature in D. ordii burrows was lower than that in burrows of D. merriami. A comparison of the diets of these animals, based on the weight per cent, and a synthetic importance value for each food item showed that while there was some dietary overlap, the diets of these two species were quite different. A comparison of the evaporative water loss and metabolism showed that D. ordii was less tolerant to high heat than D. merriami. D. merriami eliminated excessive heat loads by smearing its body with saliva and evaporating its saliva. D. ordii was not observed to eliminate excess body heat in this way.D. merriami was found to have a higher metabolic rate at low temperatures than did D. ordii, as well as less tolerance to cold, which suggests that the physiological characteristics of these species are important factors affecting their overall distribution. It was concluded that these species were well separated ecologically, and that there was little or no reason to consider them to be competing with one another.