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The length of gestation is the number of days between fertilization and parturition, and the length of lactation is the number of days between parturition and weaning. Determination of these lengths is difficult for ground-dwelling squirrels such as prairie dogs, marmots, and ground squirrels that usually copulate, give birth, and nurse offspring underground. For Gunnison's prairie dogs (Cynomys gunnisoni), the mean +1 SD length of gestation is 29.3 ? 0.53 days (n = 124). The approximate length of lactation, estimated from the mean +1 SD duration between parturition and the first emergence of juveniles from the natal burrow, is 38.6 ? 2.08 days (n = 112). Published in Journal of Mammalogy, volume 78, issue 1, on...
As part of a captive-breeding program to restore extirpated Columbia Basin pygmy rabbits (Brachylagus idahoensis) to their native habitat in Washington, we documented mating and parental care behavior of these lagomorphs, which was previously unknown. Pygmy rabbits bred from late February through early June, and mating behavior consisted of chasing and brief copulations. Although presented with 1–4 mating partners and 1–6 mating opportunities annually, only 74% of females became pregnant each year. Unlike other lagomorphs, females dug a 16- to 35-cm natal burrow, usually separate from the residential burrow system, an average of 13 days after a successful copulation. Twenty-four days after copulation, females...
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Sexual segregation occurs frequently in sexually dimorphic species, and it may be influenced by differential habitat requirements between sexes or by social or evolutionary mechanisms that maintain separation of sexes regardless of habitat selection. Understanding the degree of sex-specific habitat specialization is important for management of wildlife populations and the design of monitoring and research programs. Using mid-summer aerial survey data for Dall’s sheep (Ovis dalli dalli) in southern Alaska during 1983–2011, we assessed differences in summer habitat selection by sex and reproductive status at the landscape scale in Wrangell-St. Elias National Park and Preserve (WRST). Males and females were highly...
I measured rates of growth of individual Gunnison's prairie dogs (Cynomys gunnisoni) at three towns in the Moreno Valley, New Mexico; at an established prairie dog town (site I) prior to a plague (Yersinia pestis) epizootic and at two towns reestablished after the epizootic (sites 2 and 3). Populations declined by >99% during rile epizootic. After the epizootic, adults had greater mass, and juveniles grew faster than before. At sites 2 and 3, juveniles had high interyear survival (39%), whereas at site I, prior to plague, survival of juveniles was 17%. At sites 2 and 3, yearlings bred, whereas they did not al site 1. Mean litter size near the end of lactation was 1.5 at site 1 and 5.0 at sites 2 and 3. Application...
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This study addressed the initial effects of a reintroduction of Gunnison's prairie dogs (Cynomys gunnisoni) on resident small mammal and plant communities on the Sevilleta National Wildlife Refuge (SNWR), New Mexico. In spring 1997, 60 prairie dogs (36.8 kg live mass) were introduced onto a former prairie dog colony in a desert grassland site. Small mammals and vegetation were sampled on both a treatment (reintroduction site) and a control site (without prairie dogs) before and after the prairie dogs were reintroduced. We tested for differences in small mammal and plant community change during the 1st year of the colony's existence using repeated measures analysis of variance. Although prairie dog biomass was ca....
Because most animals copulate surreptitiously, estimates of male and female copulatory success are elusive. Here I describe six distinctive behaviors that coincide with underground copulations of Gunnison's prairie dogs (Cynomys gunnisoni): the underground consortship itself, inordinate male attention toward the estrous female, self-licking of genitals, dustbathing, the mating call, and late final submergence of the estrous female. These diagnostic behaviors allowed me to identify sexual partners for 308 females that came into estrus during a 7-year study. Published in Journal of Mammalogy, volume 79, issue 3, on pages 887 - 897, in 1998.
Determining occurrence and distribution is an essential 1st step in conservation planning for rare species. Spatial habitat models can be used to increase efficiency of field surveys and to improve understanding about factors influencing animal distributions. We used a modeling approach to identify and prioritize potential habitat for survey efforts for an uncommon mammal, the pygmy rabbit (Brachylagus idahoensis), for which detailed habitat data are limited. A base map of potential habitat in Idaho was defined using vegetation type and soil depth data. Documented locations (n = 164) were used to evaluate additional habitat variables to prioritize the potential habitat for surveys. We conducted field surveys to...
The kit fox, Vulpes macrotis nevadensis Goldman, is perhaps the least known of the Canidae found in Utah, and most of the Utah literature on this animal is concerned with taxonomy and distribution. In his revised account of Utah mammals, Barnes (1927) listed the kit fox as Vulpes velox velox and commented on its abundance in the state. Fautin (1946) mentioned it as a major influent in the northern desert shrub biome in western Utah and included some observations on food habits. Durrant (1952) mapped the kit fox distribution for the state and listed Utah specimens examined by him as referable to Vulpes macrotis nevadensis. This paper presents the results of a kit fox study made from July, 1951, to July, 1955, in...
Of the 3 major factors (habitat loss, poisoning, and disease) that limit abundance of prairie dogs today, sylvatic plague caused by Yersinia pestis is the I factor that is beyond human control. Plague epizootics frequently kill > 99% of prairie dogs in infected colonies. Although epizootics of sylvatic plague occur throughout most of the range of prairie dogs in the United States and are well described, long-term maintenance of plague in enzootic rodent species is not well documented or understood. We review dynamics of plague in white-tailed (Cynomys leucurus), Gunnison's (C gunnisoni), and black-tailed (C ludovicianus) prairie dogs, and their rodent and flea associates. We use epidemiologic concepts to support...
Characterizing circadian activity patterns is one of the essential steps to understanding how a species interacts with its environment. This study documented activity patterns of pygmy rabbits (Brachylagus idahoensis) in free-ranging populations at 5 sites in Nevada and California. Infrared-triggered camera systems were placed within areas occupied by populations of pygmy rabbits and operated for 1 year. The number of photographs obtained per hour was used as an index of aboveground activity. Activity was analyzed for diel and seasonal patterns as well as for differences among populations. All populations showed a bimodal diel activity pattern with most activity occurring at dawn and at dusk during all seasons....
Resting metabolic rate of pygmy rabbits (0.89 ml 02 g-1 h-1) was high compared to other eutherian mammals, but not unusual among lagomorphs. The estimated size of the zone of thermoneutrality was ca. 8-90C, with the lower critical temperature occurring between 15 and 200C, depending on body mass. Minimum thermal conductance was lower and mean body temperature was higher than predicted for similarly sized mammals. Body temperature fluctuated > 1?C within a 24-h period, but showed no circadian patterns. Pygmy rabbits are thermally stressed during harsh winters in Wyoming, but low thermal conductance, a highenergy source of food, and favorable microenvironments enhance survival. Published in Journal of Mammalogy, volume...
Feasibility of assigning parentage using variable microsatellite loci was assessed for 2 species of prairie dogs. Parentage was determined from 7 microsatellite loci for 46% of juveniles born during 1994 in a colony of Gunnison's prairie dogs (Cynomys gunnisoni), and for 53% and for 45% of juveniles born during 1996 and 1997, respectively, in a colony of Utah prairie dogs (C. parvidens). Frequency of multiple paternity estimated for Gunnison's (77%) and Utah (71% and 90%) prairie dogs was greater than that detected previously for black-tailed prairie dogs (5%-10%) but within the range reported for other ground-dwelling squirrels. Of the 84 adult females and 33 adult males present during 1994 in the colony of Gunnison's...
Hibernation and accompanying torpor have not been well documented in the prairie dogs (Cynomys). Members of the subgenus Leucocrossuromys are inactive during winter (Cynomys gunnisoni, Fitzgerald and Lechleitner, 1974; C. leucurus, Clark, 1977; Tileson and Lechleitner, 1966; C. parvidens, Egoscue and Frank, 1984), but some members of the subgenus Cynomys apparently do not hibernate (C. ludovicianus, Hamilton and Pfeiffer, 1977; King, 1955). To determine whether C. gunnisoni displays large drops in body temperature characteristic of torpor (Lyman, 1982), temperature-sensitive biotelemeters were implanted in captive animals so that their body temperatures could be monitored throughout one winter Published in Journal...
The use of molecular techniques for the assessment of familial relationships among social species of mammals has become relatively commonplace. However, some species represent poor candidates for such studies due to naturally low levels of genetic diversity, leading to unacceptably large standard errors associated with estimates of relatedness. Here, we report on a preliminary study of genetic diversity within two populations of a social species of ground squirrel, Gunnison's prairie dog (Cynomys gunnisoni) using DNA fingerprinting. We observed low levels of diversity in the form of large mean coefficients of genetic similarity among individuals occupying the same population. Overall similarity, determined from...
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North American desert rodents in the family Heteromyidae live in an unpredictable environment characterized by extremes in temperature and food availability; therefore, the ability to hoard food is a vital adaptation. Although much laboratory research has investigated food-hoarding tactics of heteromyid rodents, data from natural systems are scarce. We used a combination of fluorescently labeled seeds and observations of focal individuals to evaluate food-hoarding behavior in wild Merriam's kangaroo rats (Dipodomys merriami) living in different competitive environments. There was considerable individual variation within populations in the tendency to larderhoard seeds in a burrow versus scatterhoard seeds in widely...
We monitored movements of small mammals resident on floodplains susceptible to spring floods to assess whether and how these animals respond to habitat inundation. The 2 floodplains were associated with 6th order river segments in a semiarid landscape; each was predictably inundated each year as snowmelt progressed in headwater areas of the Rocky Mountains. Data from live trapping, radiotelemetry, and microtopographic surveys indicated that Peromyscus maniculatus, Microtus montanus, and Dipodomys ordii showed different responses to inundation, but all reflected a common tendency to remain in the original home range until "forced" to leave. The reluctance of Dipodomys ordii to abandon the home burrow often resulted...
ABSTRACT.-Water loss rates (W1) were determined by tritium dilution for free-ranging kit foxes (Vulpesm acrotis), for unrestrained desert coyotes (Canis latrans), and for kit foxes in a naturally landscaped outdoor enclosure Coyote W 1 was much greater in summer than in winter (P < 0.001). Seasonal variation of W1 was not statistically apparent in kit foxes. The weight specific water loss of kit foxes was intermediat beetween summer and winter rates in coyotes. Kit fox WI was 65% of that predicted on the basis of body weight, whereas W1 for summer coyotes was 155% of predicted. Metabolic water was estimated to contribute 18% of total daily water requirements for kit foxes and approximately 10 % for coyotes in summer....
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Habitat use and relative abundance of the spotted bat, Euderma maculatum, were examined in the river canyons of Dinosaur National Monument, Colorado, by monitoring audible echolocation calls. Spotted bats were found at all canyon sites, but were less common than other species of bats. We found no indications of foraging habitat restrictions. Spotted bats foraged ca. 10 m high and were active from dusk into the early morning hours. Published in Journal of Mammalogy, volume 73, issue 3, on pages 547 - 551, in 1992.
Of the five species of prairie dogs (Cynomys), only the black-tailed prairie dog (Cynomys ludovicianus) has been studied extensively. Its life history, ecology, and behavior have been documented by Hoogland (1979a, 1979b, 1981a, 1981b, 1982, 1983), King (1955), Koford (1958), Smith (1958), Tileston and Lechleitner (1966), and Waring (1970). Information regarding the remaining species is scant. The biology of the Gunnison's prairie dog (Cynomys gunnisoni) has been studied by Longhurst (1944) and Fitzgerald and Lechleitner (1974), but the diet of this species has received little attention. Published in Journal of Mammalogy, volume 69, issue 4, on pages 835 - 841, in 1988.
The desert pocket mouse (Chaetodipus penicillatus) comprises 6 nominate subspecies that occupy warm, sandy desert-scrub habitats across the Mojave and Sonoran deserts. The most thorough morphological assessment within the species noted variable levels of distinctiveness, leading to uncertainty regarding the geographic distributions of subspecies. Subsequent genetic assessments using chromosomal, allozymic, and mitochondrial DNA (mtDNA) sequence data detected a general east?west divergence centered on the Colorado River, but few locations were included in these assessments. We investigated phylogeographic structure in C. penicillatus by sequencing regions of mtDNA for 220 individuals from 51 locations representing...
map background search result map search result map Competitive environment affects food-hoarding behavior of Merriam's kangaroo rats (Dipodomys merriami) Responses of small mammals and vegetation to a reintroduction of Gunnison's prairie dogs Observations on the Spotted Bat, Euderma maculatum, in Northwestern Colorado Summer habitat selection by Dall’s sheep in Wrangell-St. Elias National Park and Preserve, Alaska Competitive environment affects food-hoarding behavior of Merriam's kangaroo rats (Dipodomys merriami) Responses of small mammals and vegetation to a reintroduction of Gunnison's prairie dogs Observations on the Spotted Bat, Euderma maculatum, in Northwestern Colorado Summer habitat selection by Dall’s sheep in Wrangell-St. Elias National Park and Preserve, Alaska