| arthropod vectors and vector-borne bacterial pathogens in yosemite national park. | ticks, fleas, and vector-borne pathogens were surveyed in diverse small mammals in yosemite national park, california, from 2005 to 2007. a total of 450 unique captures of small mammals was collected during a 3-yr period and yielded 16 species of fleas and 10 species of ticks, including known vectors of anaplasma phagocytophilum and borrelia burgdorferi and plague. serology was performed for a. phagocytophilum, spotted fever group rickettsia spp., b. burgdorferi, and yersinia pestis. a. phagocyt ... | 2011 | 21337955 |
| ground squirrel shooting and potential lead exposure in breeding avian scavengers. | recreational ground squirrel shooting is a popular activity throughout the western united states and serves as a tool for managing ground squirrel populations in agricultural regions. belding's ground squirrels (spermophilus beldingi) are routinely shot in california, nevada, and oregon across habitats that overlap with breeding avian scavengers. ground squirrels shot with lead (pb)-based bullets may pose a risk to avian scavengers if they consume carcasses containing pb fragments. to assess the ... | 2016 | 27942006 |
| cryptosporidium rubeyi n. sp. (apicomplexa: cryptosporidiidae) in multiple spermophilus ground squirrel species. | previously we reported the unique cryptosporidium sp. "c" genotype (e.g., sbey03c, sbey05c, sbld05c, sltl05c) from three species of spermophilus ground squirrel (spermophilus beecheyi, spermophilus beldingi, spermophilus lateralis) located throughout california, usa. this follow-up work characterizes the morphology and animal infectivity of this novel genotype as the final step in proposing it as a new species of cryptosporidium. analysis of sequences of 18s rrna, actin, and hsp70 genes of addit ... | 2015 | 26543805 |
| eimeria beldingii n. sp. and other coccidia (apicomplexa) of the ground squirrel spermophilus beldingi. | fecal samples of 36 ground squirrels, spermophilus beldingi, from tioga pass (elev. ca. 3315 m) in the sierra nevada, california, yielded oocysts of eimeria beckeri in nine squirrels, e. citelli in four squirrels, e. beldingii n. sp. in two squirrels, and degenerated, unidentifiable oocysts in ten squirrels. eimeria beldingii n. sp. oocysts are ellipsoidal, 30-34 x 24-30 (mean 32 x 26) micron with a two-layered, rough, striated wall, without a micropyle or residuum, with polar granules; they con ... | 1984 | 6470992 |
| plasma glucocorticoid concentrations and body mass in ground squirrels: seasonal variation and circannual organization. | we examined variation in plasma glucocorticoid concentrations of free-living belding's ground squirrels (spermophilus beldingi) and captive golden-mantled ground squirrels (spermophilus lateralis) housed in constant environmental conditions. plasma corticosterone concentrations were not significantly correlated with time held captive in traps prior to collection of blood samples in males or non-breeding females, but these variables were significantly correlated in breeding females during the pre ... | 2006 | 16360155 |
| the ontogeny of kin-recognition mechanisms in belding's ground squirrels. | despite extensive research on the functions and mechanisms of kin recognition, little is known about developmental changes in the abilities mediating such recognition. belding's ground squirrels, urocitellus beldingi, use at least two mechanisms of kin recognition in nepotistic contexts: familiarity and phenotype matching. because recognition templates develop from early associations with familiar kin (and/or with self), familiarity-based recognition should precede phenotype-matching recognition ... | 2017 | 28242467 |
| within-individual correlations reveal link between a behavioral syndrome, condition and cortisol in free-ranging belding's ground squirrels. | animals often exhibit consistent individual differences in behavior (i.e. animal personality) and correlations between behaviors (i.e. behavioral syndromes), yet the causes of those patterns of behavioral variation remain insufficiently understood. many authors hypothesize that state-dependent behavior produces animal personality and behavioral syndromes. however, empirical studies assessing patterns of covariation among behavioral traits and state variables have produced mixed results. new stat ... | 2015 | 25598565 |
| development, maternal effects, and behavioral plasticity. | behavioral, hormonal, and genetic processes interact reciprocally, and differentially affect behavior depending on ecological and social contexts. when individual differences are favored either between or within environments, developmental plasticity would be expected. parental effects provide a rich source for phenotypic plasticity, including anatomical, physiological, and behavioral traits, because parents respond to dynamic cues in their environment and can, in turn, influence offspring accor ... | 2014 | 24820855 |
| chronically raised glucocorticoids reduce innate immune function in belding's ground squirrels (urocitellus beldingi) after an immune challenge. | the hypothalamic-pituitary-adrenal (hpa) axis releases glucocorticoids (gcs), or stress hormones, during the vertebrate stress response. gcs can both enhance and suppress the immune system depending on whether the experienced stressor is acute or chronic and what aspect of immune function is measured. more research is needed to fully understand how the immune system reacts to stressors. in this study, we examined the effects of chronically raised gcs on innate immune function in belding's ground ... | 2013 | 23948370 |
| anthropogenic refugia ameliorate the severe climate-related decline of a montane mammal along its trailing edge. | we conducted detailed resurveys of a montane mammal, urocitellus beldingi, to examine the effects of climate change on persistence along the trailing edge of its range. of 74 california sites where u. beldingi were historically recorded (1902-1966), 42 per cent were extirpated, with no evidence for colonization of previously unoccupied sites. increases in both precipitation and temperature predicted site extirpations, potentially owing to snowcover loss. surprisingly, human land-use change buffe ... | 2012 | 22896652 |
| how habitat features shape ground squirrel (urocitellus beldingi) navigation. | the purpose of this investigation was to determine whether belding's ground squirrels (urocitellus beldingi) from areas rich in beacons perform differently in a task of spatial memory compared with squirrels from beacon-thin areas. to assess the role of environmental experience in spatial memory, wild-born squirrels with several days of experience in the field were compared with squirrels born in a lab and with no experience in their original habitat. over two summers, squirrels captured from be ... | 2010 | 20476817 |
| alarm calls elicit predator-specific physiological responses. | glucocorticoids regulate glucose concentrations and responses to unpredictable events, while also modulating cognition. juvenile belding's ground squirrels (urocitellus beldingi) learn to respond to whistle and trill alarm calls, warning of aerial and terrestrial predators, respectively, shortly after emerging from natal burrows at one month of age. alarm calls can cause physiological reactions and arousal, and this arousal, coupled with watching adult responses, might help juveniles learn assoc ... | 2010 | 20236965 |
| inverted-u shape relationship between cortisol and learning in ground squirrels. | adrenal hormones regulate glucose levels, responses to unpredictable stressors and modulate cognition. glucocorticoids can have an inverted-u shape relationship with cognition, as very low or high levels impair, whereas moderate elevations facilitate, acquisition and retention of memories. to date these relationships have been tested with humans and rodents in laboratory settings rather than with wild animals in biologically relevant contexts. this study examined whether the elevated cortisol ob ... | 2008 | 18164635 |
| ecological and hormonal correlates of antipredator behavior in adult belding's ground squirrels (spermophilus beldingi). | predator-prey relationships provide an excellent opportunity to study coevolved adaptations. decades of theoretical and empirical research have illuminated the various behavioral adaptations exhibited by prey animals to avoid detection and capture, and recent work has begun to characterize physiological adaptations, such as immune reactions, metabolic changes, and hormonal responses to predators or their cues. a 2-year study quantified the activity budgets and antipredator responses of adult bel ... | 2007 | 20336174 |
| development of individually distinct recognition cues. | despite extensive research on the functions of kin recognition, little is known about ontogenetic changes in the cues mediating such recognition. in belding's ground squirrels, spermophilus beldingi, secretions from oral glands are both individually distinct and kin distinct, and function in social recognition across many contexts. behavioral studies of recognition and kin preferences suggest that these cues may change across development, particularly around the time of weaning and emergence fro ... | 2006 | 17016836 |
| developmental and geographic variation in stress hormones in wild belding's ground squirrels (spermophilus beldingi). | extensive research has been conducted on the role of glucocorticoids in regulating growth, mobilizing energy, responding to stressors and modulating learning and memory. however, little is known about the production of corticoids during early development in free-living animals, particularly during sensitive periods of acquisition of important behaviors. in a four-year study of belding's ground squirrels, spermophilus beldingi, a non-invasive assay of glucocorticoids was used to quantify age and ... | 2006 | 16890229 |
| a validation of extraction methods for noninvasive sampling of glucocorticoids in free-living ground squirrels. | fecal hormone assays provide a powerful tool for noninvasive monitoring of endocrine status in wild animals. in this study we validated a protocol for extracting and measuring glucocorticoids in free-living and captive belding's ground squirrels (spermophilus beldingi). we first compared two commonly used extraction protocols to determine which performed better with commercially available antibodies. we next verified the preferred extraction method by correlating circulating and fecal glucocorti ... | 2017 | 16228945 |
| food supplements modulate changes in leucocyte numbers in breeding male ground squirrels. | immunosuppression may be an important cost of reproduction in breeding males. it can result from elevated levels of testosterone or stress hormones and may serve to lower the energetic cost of maintaining immune function at a time of high demand. this suggests that greater access to energy resources could reduce immunosuppression as a cost of reproduction, minimizing the trade-off between energetic investment in current reproductive effort and survival. i examined the impact of food availability ... | 2003 | 12796454 |
| kin-recognition abilities and nepotism as a function of sociality. | despite widespread interest in kin selection and nepotism, relatively little is known about the perceptual abilities of animals to recognize their relatives. here i show that a highly nepotistic species, belding's ground squirrels (spermophilus beldingi), produces odours from at least two sources that correlate with relatedness ('kin labels'), and that ground squirrels can use these odours to make accurate discriminations among never before encountered ('unfamiliar') kin. recognition odours appe ... | 2002 | 11934364 |
| individual acoustic variation in belding's ground squirrel alarm chirps in the high sierra nevada. | | 2002 | 11931291 |
| food availability affects behavior but not circulating gonadal hormones in maternal belding's ground squirrels. | we tested predictions of hypotheses suggesting that the steroid hormones, testosterone (t), progesterone (p), and estradiol (e2), contribute to the energetic regulation of behaviors associated with rearing young in free-living female belding's ground squirrels (spermophilus beldingi). we provisioned some female s. beldingi with food rich in fat and calories, and used unprovisioned females as controls. we observed the behavior of females throughout the reproductive cycle, and regularly collected ... | 2000 | 11239662 |
| retention of social recognition after hibernation in belding's ground squirrels. | the retention of social memory during long periods of separation, such as hibernation or migration, has not been well documented, despite evidence for long-term social relationships in migrating species or in long-lived sedentary species. we investigated the ability of captive belding's ground squirrels, spermophilus beldingi, to remember previously familiar individuals as well as littermates after 9 months of isolation. before hibernation, young ground squirrels discriminated between odours of ... | 2000 | 10715170 |
| endocrine and energetic mediation of play behavior in free-living belding's ground squirrels. | many juvenile mammals play, and rates and patterns of play behavior often differ between young males and females. the sexual dimorphisms typical of mammalian play suggest that it might be influenced by gonadal hormones. moreover, because play competes with growth, physical development, and acquisition of fat reserves for available energy, play behavior should theoretically be influenced by energetic variables. we examined patterns of social play behavior and endocrine and energetic mediation of ... | 1999 | 10506539 |
| energetic and endocrine mediation of natal dispersal behavior in belding's ground squirrels. | natal dispersal, the permanent departure of an individual from its birth site, is sex biased in most mammals, with males dispersing at higher rates or over greater distances than do female conspecifics. because dispersal movements may be energetically expensive, their occurrence should theoretically be influenced by energy availability. moreover, the male bias typical of mammalian dispersal suggests that this behavior might be mediated by gonadal androgens. using free-living belding's ground squ ... | 1999 | 10202119 |
| how mothers influence the development of litter-mate preferences in belding's ground squirrels. | we performed three experiments to examine the role of mothers in the development of litter-mate preferences in captive juvenile belding's ground squirrels, spermophilus beldingi. first, when observed in the absence of mothers, juveniles did not play preferentially with litter-mates, which suggests that mothers somehow influence the ontogeny of litter-mate preferences. second, when mothers were present but unable to intervene in social interactions, juveniles displayed litter-mate preferences, wh ... | 1998 | 9642000 |
| body fat and time of year interact to mediate dispersal behaviour in ground squirrels | behaviour is often influenced by energy availability. hibernation presents an energetic challenge to belding's ground squirrels, spermophilus beldingi, which depend entirely on stored energy for survival during their 8-9 month dormant period each year. dispersal from the natal area may also place energetic demands on s. beldingi. in this study, we assessed the relationship between dispersal behaviour, body mass and body fat of juvenile male s. beldingi over 3 consecutive years, one of which had ... | 1998 | 9515050 |
| development of alarm-call responses in belding's ground squirrels: the role of dams | experiences with adult conspecifics can influence the ontogeny of species-typical behaviours in naive young of many species. two processes of influence, direct and indirect, are proposed to describe the effect of adult behaviours on juvenile development. in belding's ground squirrels, spermophilus beldingiexposure to adults experienced with responding to alarm calls may affect how juveniles respond to calls and/or the rate at which juveniles acquire adult-like responses to calls. because dams an ... | 1997 | 9299037 |
| temporal aspects in the development of belding's ground squirrels' litter-mate preferences | four experiments were conducted to determine how experience around the time of natal emergence affected the development of litter-mate preferences in juvenile belding's ground squirrels, spermophilus beldingisocial preferences were ascertained by observing six captive groups, each housed in outdoor enclosures beginning at natal emergence, and recording the frequency of dyadic play. juveniles preferred their litter-mates as play partners on day 1 above-ground, demonstrating that pre-emergent inte ... | 1997 | 9236028 |
| early auditory experience and the ontogeny of alarm-call discrimination in belding's ground squirrels (spermophilus beldingi). | because young ground squirrels are vulnerable to predation, selection would favor the early ability to respond to alarm calls. this requires discrimination of classes of alarm calls from each other as well as from non-alarm calls. pre-emergent auditory experience may influence the development of discrimination. as a means of determining when belding's ground squirrels (spermophilus beldingi) can discriminate among calls, cardiac responses to alarm calls and control stimuli were recorded from 2 r ... | 1996 | 8681525 |
| mate guarding as paternity insurance in idaho ground squirrels. | following a copulation, males in many species of vertebrates (particularly birds) and invertebrates remain near the inseminated female and repel other suitors with displays or force. guarding males must delay resumption of competitive mate searching, but they may insure their paternity by reducing possibilities for secondary matings and sperm competition. among mammals, post-copulatory mate guarding has been reported in rodents, mongooses, ungulates and primates, including humans, but the effect ... | 1989 | 2927502 |
| vaginal estrus in unmated belding's ground squirrels. | belding's ground squirrels are seasonally breeding rodents that have a single annual mating season (ca. 3 weeks long) which begins shortly after their vernal emergence from a 7-month period of hibernation. in this study, changes in vaginal estrus were assessed among unmated captive females. following a 7-month period in a coldroom, vaginal lavages were taken daily to monitor changes in estrous condition. females were in vaginal estrus within 24-48 hr of removal from the coldroom. rather than exh ... | 1986 | 3721416 |
| ketone body metabolism in a ground squirrel during hibernation and fasting. | hibernating belding's ground squirrels (spermophilus beldingi) are ketotic relative to fed nonhibernators. muscles from torpid individuals, when incubated in media containing physiological concentrations of glucose and ketone, show reduced uptake of glucose in the presence of ketone. the magnitude of the reduction is dependent on ketone concentration and reaches 60% in heart and 100% in pectoralis at 1.4 mm ketone. fasted squirrels are also ketotic. however, ketone does not reduce glucose uptake ... | 1985 | 4051032 |
| body temperatures and heart rates of laboratory rats and belding squirrels (spermophilus beldingi) during behavioral thermoregulation. | | 1975 | 1199 |
| sexual maturation in male belding's ground squirrels: influence of body weight. | the relation between body weight and sexual maturation was examined in a hibernator, belding's ground squirrel, by manipulating the availability of food to weaned juvenile males. following body weight manipulation in the summer, testicular growth, serum testosterone, and spermatogenesis were monitored during the subsequent year, which included 7 mo when males were in the coldroom (ca. 8 degrees c), followed by 5 mo in the laboratory (ca. 20 degrees c). juveniles (less than 1 yr old) maintained o ... | 1985 | 4041521 |
| hormonal influences on natal dispersal in free-living belding's ground squirrels (spermophilus beldingi). | preliminary identification of the physiological causes of natal dispersal in two populations of free-living belding's ground squirrels (spermophilus beldingi) was attempted in the sierra nevada of california. two competing hypotheses, each suggesting a different endocrinological cause for natal dispersal in this species were tested. data collected by observation, trapping, and telemetry during three field seasons (1979-1981) contradict predictions of the hypothesis that concurrent, high levels o ... | 1984 | 6519659 |
| effects of temperature on the duration of arousal episodes during hibernation. | the length of time that the ground squirrels spermophilus beldingi and s. lateralis remained at high body temperatures following periodic arousals from hibernation increased as environmental temperature increased over the range of 5-20 degree c. this trend was evident in comparisons among different animals that hibernated at different temperatures and in individuals that hibernated at different temperatures in successive years. at any one temperature, the duration of these euthermic intervals in ... | 1982 | 7061268 |
| multiple paternity in belding's ground squirrel litters. | sexually receptive female spermophilus beldingi (rodentia: sciuridae) usually mate with several different males. the paternity of 27 litters born in 1977 and 1978 was ascertained by combining field observations of mating with laboratory paternity exclusion analyses. most of the litters (78 percent) were multiply sired, usually by two or three males. this may be the highest frequency of multiple paternity ever directly demonstrated in a natural population. | 1981 | 7209536 |
| seasonal changes in plasma proteins and lipids in the belding ground squirrel (spermophilus beldingi beldingi). | | 1976 | 57024 |
| chromosomal aberrations in a population of ground squirrels. | chromosomes were analyzed from a population of spermophilus beldingi that included an adult female and three juveniles from the same burrow. all animals had a diploid number of 30. the adult and a juvenile female from the burrow had identical aberrant karyotypes containing an unpaired submetacentric and a minute metacentric chromosome. a familial aberration involving an x chromosome, without phenotypic alteration, is most probable. | 1966 | 5903584 |
| chromosomes of the ground squirrel spermophilus beldingi and report of an aberrant karyotype in a phenotypically normal female. | | 1965 | 14291490 |
| efficacy and nontarget impact of zinc phosphide-coated cabbage as a ground squirrel management tool. | effective management of ground squirrels relies on an integrated pest management (ipm) approach. rodenticides may be included in an ipm program, but they must be efficacious with minimal impact on nontarget species. a zinc phosphide-coated green bait may meet these requirements. we established a study in northeastern california to test zinc phosphide-coated cabbage as a management tool for belding's ground squirrels (urocitellus beldingi). we specifically addressed factors that would influence t ... | 2019 | 30632260 |