TL;DR: In general, the greatest diurnal variation in body temperature appears to occur in the smallest mammals and is probably related to their high energy requirements.
Abstract: DURING our recent efforts to review estivation and relate it to hibernation (Hudson and Bartholomew, 1964) we became convinced of the paucity of data for definition of the normal spectrum of temperature regulation of homeotherms and heterotherms-an essential step prior to differentiation of hibernation, estivation, and heterothermy. While many species of mammals exhibit daily cycles of body temperatures, in some cases the amplitude of the cycle may vary widely enough to be designated as torpidity (Morrison and Ryser, 1959; Tucker, 1962). Some species of small mammals allow their body temperatures to drop below levels considered typical of non-hibernators yet cannot survive body temperatures as low as those routinely tolerated by the hibernators (Kayser, 1961; Tucker, 1962; MacMillen, 1964). In general, the greatest diurnal variation in body temperature appears to occur in the smallest mammals and is probably related to their high energy requirements. Baiomys taylori is a very small cricetid rodent weighing between 6 and 9 g whose origin is subtropical with a distribution extending only to the southern part of the western United States (Blair, 1941). The study of its temperature regulation
TL;DR: A model for the composition of rodent communities in grass/shrublands of the Southwest and Intermountain West, based on ground cover is proposed, which suggests kangaroo rats are abundant in areas with the most bare soil, Muridae dominate areasWith the most and tallest ground cover, and pocket mice are common in areas of intermediate cover.
Abstract: We live-trapped rodents in 2000–2001 at eight sites on a 3160 ha grassland and mesquite-oak savanna in southeastern Arizona that had been ungrazed since 1968, and on eight paired sites on adjacent cattle ranches. There were 917 captures of 14 species during 5760 trap-nights. Four species of Muridae (Sigmodon fulviventer, Baiomys taylori, Reithrodontomys megalotis and R. fulvescens) were significantly more common on ungrazed plots, while no species was more abundant on grazed plots. However, Heteromyidae as a group (especially Chaetodipus hispidus and Perognathus flavus) comprised a significantly higher proportion of total captures on grazed plots, and heteromyids as a percentage of total captures was positively correlated across all plots with amount of bare ground. One of the eight cross-fence sites also had been trapped in 1981–1983. In the 17 y between trapping events at this site: (1) the grass canopy on both grazed and ungrazed plots had become dominated by taller species, (2) a kangaroo rat...
TL;DR: A longitudinal study of Bayou virus, the second-leading agent of hantavirus pulmonary syndrome in the United States, finds patterns in seroprevalence similar to those of SNV and can be used in identification of potentially at-risk areas.
Abstract: What is currently known about the ecology of North American hantaviruses has come largely from studies on Sin Nombre virus (SNV). We conducted a longitudinal study of Bayou virus (BAYV), the second-leading agent of hantavirus pulmonary syndrome in the United States. Antibodies to hantavirus were detected from Oryzomys palustris (most commonly infected species), Sigmodon hispidus, Peromyscus leucopus, Reithrodontomys fulvescens, and Baiomys taylori. However, only O. palustris had viral RNA in tissues and excreta, suggesting that antibodies detected in other species may have resulted from spill-over infection. Seroprevalence rates averaged around 16% for O. palustris and varied seasonally. The heaviest males exhibited the highest levels of seroprevalence. Seroprevalence was higher in coastal prairie (20.0%) than old-fields (10.5%) and was associated with host abundance. These patterns are similar to those of SNV and can be used in identification of potentially at-risk areas.
TL;DR: Both a minimum body weight and a minimum time for development after birth are necessary for homeometabolism, and in all species the ability for sustained increase coincided with the first occurrence of obvious shivering and piloerection.
TL;DR: The response of the northern pygmy mouse to two densities of the red imported fire ant in a 17-month field experiment was examined, indicating burrows were not located randomly with respect to foraging activity of fire ants.
Abstract: We examined the response of the northern pygmy mouse ( Baiomys taylori ) to two densities of the red imported fire ant ( Solenopsis invictd ) in a 17-month field experiment conducted ca. 60 km north of Corpus Christi, Texas. Colonies of fire ants were removed from one-half of each of two sampling grids. In the postremoval period, there were significantly more new captures of Baiomys in areas of low density of ants than in areas of original density. Time required to recruit five worker S. invicta to bait cups placed around burrows used by Baiomys was significantly longer than the time required to recruit to bait around random points, indicating burrows were not located randomly with respect to foraging activity of fire ants.