| the effects of the light:dark cycle and sympathetically-active drugs on pineal n-acetyltransferase activity and melatonin content in the richardson's ground squirrel, spermophilus richardsonii. | when adult richardson's ground squirrels, born in the wild, are kept in the laboratory under light:dark cycles of 14:10 (lights out at 2000 h), pineal n-acetyltransferase (nat) activity and melatonin levels begin to rise shortly after lights out; both reach peak levels by 4 h into the dark phase. the rise in pineal nat activity is partially blocked by phentolamine, an alpha-receptor blocker, and totally blocked by propranolol, a beta-receptor blocker. phentolamine had no inhibitory influence on ... | 1982 | 7202214 |
| hibernation in thyroidectomized ground squirrels, spermophilus richardsoni. | | 1981 | 7227815 |
| absence of evidence for a hibernation "trigger" in blood dialyzate of richardson's ground squirrel. | | 1979 | 477365 |
| effects of central injection of biogenic amines during arousal from hibernation. | simultaneous measurements of heat production (hp) and heat loss (hl) and brain and rectal temperatures were made in richardon's ground squirrels (spermophilus richardsonii) rewarming from hibernation at an ambient temperature of 6.0 +/- 0.5 degrees c. calculations from hp and hl measurements from control animals showed that due to differential rewarming, there was a reduction of apparent specific heat of the animal to 0.59 cal/g. degrees c. this resulted in an energy saving of 30%. three intrace ... | 1979 | 426092 |
| effect of age and parity on weight gain and entry into hibernation in richardson's ground squirrels. | | 1978 | 751708 |
| thyroxine metabolism in active and torpid ground squirrels, spermophilus richardsoni. | | 1978 | 658662 |
| studies on immunoglobulins of richardson's ground squirrel--i. characterization of ground squirrel igg. | | 1978 | 640712 |
| serum t4 and t3 in active and torpid ground squirrels, spermophilus richardsoni. | | 1978 | 566236 |
| seasonal variations in the renal cortical (na+ + k+)-atpase and mg2+-atpase of a hibernator, the ground squirrel (spermophilus richardsonii). | 1. the specific activity of renal cortical (na+ + k+)-atpase of the richardson ground squirrel is markedly reduced during hibernation, in contrast to the specific activity of the accompanying mg2+-atpase which is markedly increased. 2. the sensitivity of (na+ + k+)-atpase to inhibition by ouabain is unchanged by hibernation. 3. both the non-linear thermal dependence of (na+ + k+)-atpase and the linear thermal dependence of mg2+-atpase are also unchanged by hibernation. 4. the energy of activatio ... | 1978 | 233796 |
| mitochondrial alpha-glycerophosphate dehydrogenase activity in active and torpid ground squirrels, spermophilus richardsoni. | 1. mitochondrial alpha-glycerophosphate dehydrogenase (gpd) activity was assayed in liver homogenates from active and torpid ground squirrels. 2. arrhenius plots of gpd activity were linear in non-hibernating animals and discontinuous in hibernators. compared with non-hibernators, the energy of activation in hibernators was reduced between 37 and 25 degrees c, but increased between 25 and 6 degrees c. 3. a dose-response relation between gpd activity and injected thyroxine was determined in activ ... | 1978 | 318284 |
| variations in (na+ + k+)-atpase and mg2+-atpase activity of the ground squirrel brain during hibernation. | 1. the specific activity of brain (na+ + k+)-atpase and mg2+ -atpase of the ground squirrel (spermophilus richardsonii) is significantly increased after long-term hibernation. 2. the markedly non-linear thermal dependence of (na+ + k+)-atpase is unchanged during hibernation whereas the near linear thermal dependence of mg2+-atpase undergoes minor alteration after prolonged hibernation. 3. the sensitivity of (na+ + k+)-atpase to inhibition by ouabain is significantly decreased after 100 days of h ... | 1978 | 233776 |
| thermoregulatory effects of central injection of noradrenaline in the richardson's ground squirrel (spermophilus richardsonii). | | 1978 | 33006 |
| development of adult-young identification in richardson's ground squirrel. | | 1974 | 4421896 |
| a telemetric study of the abdominal temperature of a hibernator, spermophilus richardsonii, maintained under constant conditions of temperature and light during the active season. | | 1974 | 4840658 |
| climatic conditions and breeding in richardson's ground squirrel. | | 1973 | 4706255 |
| maternal behaviour in richardson's ground squirrel (spermophilus richardsonii richardsonii): retrieval of young by non-lactating females. | | 1973 | 4735941 |
| reproduction of richardson's ground squirrel (spermophilus richardsonii) in southern saskatchewan. | | 1972 | 4656825 |
| chromosomes of the nevada ground squirrel spermophilus richardsonii nevadensis (howell). | | 1964 | 14233474 |
| chromosomes and evolution of the ground squirrel, spermophilus richardsonii. | | 1964 | 14196876 |
| effects of scent lure on camera trap detections vary across mammalian predator and prey species. | camera traps are a unique survey tool used to monitor a wide variety of mammal species. camera trap (ct) data can be used to estimate animal distribution, density, and behaviour. attractants, such as scent lures, are often used in an effort to increase ct detections; however, the degree which the effects of attractants vary across species is not well understood. we investigated the effects of scent lure on mammal detections by comparing detection rates between 404 lured and 440 unlured ct statio ... | 2020 | 32396558 |
| richardson's ground squirrel (urocitellus richardsonii) alarm call receivers experience an auditory continuity illusion. | auditory continuity illusions are perceptual illusions in which receivers perceive an auditory signal as continuous when part of the signal has been removed or obfuscated by a louder noise. richardson's ground squirrels (urocitellus richardsonii) communicate alarm acoustically in noisy natural settings. thus, we tested whether they experience an auditory continuity illusion by presenting free-living squirrels with repeated whistle alarm calls within which every second syllable remained unmanipul ... | 2020 | 33090849 |
| pathology of ground squirrels in a research colony. | this paper presents a retrospective review of the postmortem findings in a colony of wild-caught ground squirrels used inmedical research. the species included in this study were richardson's ground squirrel urocitellus richardsonii, columbianground squirrel urocitellus columbianus and golden-mantled ground squirrel callospermophilus lateralis. the pathologicfindings in 160 ground squirrels from this colony demonstrated a wide variety of conditions, with chronic nephritis andhepatic adenomas bei ... | 2020 | 33036668 |
| characterizing the regulation of pyruvate kinase in response to hibernation in ground squirrel liver (urocitellus richardsonii). | the richardson's ground squirrel (urocitellus richardsonii) undergoes numerous changes to its core physiological and metabolic processes over the months it spends hibernating during the winter. winter torpor is characterized by an overall reduction in metabolic rate, a lowering of core body temperature, and a switch to preferential consumption of lipids instead of carbohydrates. the alterations in central metabolic pathways are often accomplished by the regulation of key enzymes within the glyco ... | 2020 | 32592750 |
| regulation of the α-ketoglutarate dehydrogenasecomplex during hibernation in a small mammal, the richardson's ground squirrel (urocitellus richardsonii). | the citric acid cycle (cac) is a central metabolic pathway that links carbohydrate, lipid, and amino acid metabolism in the mitochondria and, hence, is a crucial target for metabolic regulation. the α-ketoglutarate dehydrogenase complex (kgdc) is the rate-limiting step of the cac, the three enzymes of the complex catalyzing the transformation of α-ketoglutarate to succinyl-coa with the release of co2 and reduction of nad to nadh. during hibernation, the metabolic rate of small mammals is suppres ... | 2020 | 32445798 |
| burrowing richardson's ground squirrels affect plant seedling assemblages via environmental but not seed bank changes. | in grassland ecosystems, burrowing mammals create disturbances, providing habitat for animal species and increasing plant community diversity. we investigated whether seedling assemblages on richardson's ground squirrel urocitellus richardsonii mounds result from seed rearrangement or environmental changes that favor germination of certain species over others. to test whether ground squirrels rearrange the seed bank by burrowing, we compared seed compositions among mounds, burrows, and undisturb ... | 2020 | 32440282 |
| call-specific patterns of neural activation in auditory processing of richardson's ground squirrel alarm calls. | richardson's ground squirrels use alarm calls to warn conspecifics about potential predatory threats. chirp calls typically indicate high levels of threat from airborne predators, while whistle calls are associated with lower levels of threat from terrestrial predators. these types of calls primarily elicit escape behaviors and increased vigilance in receivers, respectively. while much is known about the neural mechanisms involved in the production of vocalizations, less is known about the mecha ... | 2020 | 32307882 |
| identification of bacteria in the rocky mountain wood tick, dermacentor andersoni, using single-strand conformation polymorphism (sscp) and dna sequencing. | pcr-based single-strand conformation polymorphism (sscp) analyses combined with dna sequencing of the prokaryotic 16s ribosomal (r) rna gene encompassing the hypervariable v4 region was used to determine the bacterial composition of rocky mountain wood ticks (dermacentor andersoni) attached to richardson's ground squirrels (urocitellus richardsonii) and questing on vegetation in southern saskatchewan, canada. the bacteria present in questing adult ticks from saskatchewan landing provincial park ... | 2020 | 31953633 |
| gone girl: richardson's ground squirrel offspring and neighbours are resilient to female removal. | within matrilineal societies, the presence of mothers and female kin can greatly enhance survival and reproductive success owing to kin-biased alarm calling, cooperation in territory defence, protection from infanticidal conspecifics, joint care of young and enhanced access to resources. the removal of mothers by predators or disease is expected to increase the stress experienced by offspring via activation of their hypothalamic-pituitary-adrenal axis, increasing circulating glucocorticoids and ... | 2019 | 31598313 |
| central distribution of oxytocin and vasopressin 1a receptors in juvenile richardson's ground squirrels. | oxytocin and vasopressin are well-conserved peptides important to the regulation of numerous aspects of social behavior, including sociality. research exploring the distribution of the receptors for oxytocin (oxtr) and for vasopressin (avpr1a) in mammals has revealed associations between receptor distribution, sociality, and species' mating systems. given that sociality and gregariousness can be tightly linked to reproduction, these nonapeptides unsurprisingly support affiliative behaviors that ... | 2019 | 30802986 |
| like mother, like daughter: heritability of female richardson's ground squirrel urocitellus richardsonii cortisol stress responses. | activation of the hypothalamic-pituitary-adrenal (hpa) axis liberates glucocorticoids, which provides an acute indication of an individual's response to stressors. the heritability of the stress response in wild mammals, however, remains poorly documented. we quantified the cortisol stress response of female richardson's ground squirrels (rgss) to handling and physical restraint, testing for: (1) the effects of individual age, time of day, and sample latency; (2) repeatability within individuals ... | 2018 | 30402055 |
| temperature and serine phosphorylation regulate glycerol-3-phosphate dehydrogenase in skeletal muscle of hibernating richardson's ground squirrels. | glycerol-3-phosphate dehydrogenase (g3pdh) bridges carbohydrate and lipid metabolism by interconverting glycerol-3-phosphate (g3p) and dihydroxyacetone phosphate (dhap). this reversible reaction converts g3p derived from triglyceride hydrolysis to dhap that can then enter glycolysis or gluconeogenesis and, in the reverse reaction, makes g3p for use in triglyceride biosynthesis. small hibernating mammals rely almost exclusively on triglyceride reserves as their fuel for energy production during t ... | 2019 | 30253108 |
| a case of rapid recurrence of apocrine ductal carcinoma originating from the oral scent gland of a richardson's ground squirrel (urocitellus richardsonii). | a 3-year-old female richardson's ground squirrel developed a subcutaneous mass at the left oral angle. seven days after removal of the mass, the mass recurred and metastasized to the cervical lymph node. histologically, the primary mass was subdivided by fibrous trabeculae into various-sized neoplastic cell lobules showing a solid growth pattern with frequent mitoses and sometimes forming intracytoplasmic lumina. large to medium-sized lobules formed a central cyst plugged by comedo necrosis. neo ... | 2018 | 30093788 |
| effects of arginine vasopressin on richardson's ground squirrel social and vocal behavior. | in nearly every vertebrate species examined thus far arginine vasopressin (avp) and its homologues modulate behavior; thus, providing rich systems for comparative research. in rodents, avp is best known for its modulation of social behavior; however, to date, research on avps effects on behavior have been limited to laboratory models and a few experiments using large outdoor enclosures. to extend our understanding of avps role in modulating social behavior and communication in an ecologically re ... | 2018 | 29553774 |