| a new hepadnavirus endemic in arctic ground squirrels in alaska. | we present evidence for a novel member of the hepadnavirus family that is endemic in wild arctic ground squirrels (spermophylus parryi kennicotti) in alaska. this virus, designated arctic squirrel hepatitis virus (ashv), was initially detected in the livers of animals bearing large hepatic nodules by nucleic acid hybridization with hepadnavirus probes and in plasma by cross-reactivity with antibodies to hepadnavirus surface and core antigens. the complete nucleotide sequence of the 3,302-bp-long ... | 1996 | 8676441 |
| detection of differential gene expression in brown adipose tissue of hibernating arctic ground squirrels with mouse microarrays. | hibernation is an energy-saving strategy adopted by a wide range of mammals to survive highly seasonal or unpredictable environments. arctic ground squirrels living in alaska provide an extreme example, with 6- to 9-mo-long hibernation seasons when body temperature alternates between levels near 0 degrees c during torpor and 37 degrees c during arousal episodes. heat production during hibernation is provided, in part, by nonshivering thermogenesis that occurs in large deposits of brown adipose t ... | 2006 | 16464973 |
| eimeria species (apicomplexa: eimeriidae) from arctic ground squirrels (spermophilus parryii) and red squirrels (tamiasciurus hudsonicus) in alaska and in siberia, russia. | fecal samples from arctic ground squirrels (spermophilus parryii) collected in alaska (n = 90) and russia (n = 46) and from red squirrels (tamiasciurus hudsonicus) in alaska (n = 35) were examined for the presence of eimeria spp. (apicomplexa: eimeriidae). four species were recovered from arctic ground squirrels, including eimeria callospermophili (prevalence = 18%), eimeria cynomysis (23.5%), eimeria lateralis (19%), and eimeria morainensis (77%). a single species, eimeria tamiasciuri (91%), wa ... | 2005 | 17089755 |
| sex-dependent phenological plasticity in an arctic hibernator. | hibernation provides a means of escaping the metabolic challenges associated with seasonality, yet the ability of mammals to prolong or reenter seasonal dormancy in response to extreme weather events is unclear. here, we show that arctic ground squirrels in northern alaska exhibited sex-dependent plasticity in the physiology and phenology of hibernation in response to a series of late spring snowstorms in 2013 that resulted in the latest snowmelt on record. females and nonreproductive males resp ... | 2017 | 29166160 |
| integrating archaeology and ancient dna analysis to address invasive species colonization in the gulf of alaska. | the intentional and unintentional movement of plants and animals by humans has transformed ecosystems and landscapes globally. assessing when and how a species was introduced are central to managing these transformed landscapes, particularly in island environments. in the gulf of alaska, there is considerable interest in the history of mammal introductions and rehabilitating gulf of alaska island environments by eradicating mammals classified as invasive species. the arctic ground squirrel (uroc ... | 2017 | 27859602 |
| how will the greening of the arctic affect an important prey species and disturbance agent? vegetation effects on arctic ground squirrels. | increases in terrestrial primary productivity across the arctic and northern alpine ecosystems are leading to altered vegetation composition and stature. changes in vegetation stature may affect predator-prey interactions via changes in the prey's ability to detect predators, changes in predation pressure, predator identity and predator foraging strategy. changes in productivity and vegetation composition may also affect herbivores via effects on forage availability and quality. we investigated ... | 2015 | 25666700 |
| diversity and demography in beringia: multilocus tests of paleodistribution models reveal the complex history of arctic ground squirrels. | to assess effects of historical climate change on northern species, we quantified the population history of the arctic ground squirrel (spermophilus parryii), an arctic-adapted rodent that evolved in beringia and was strongly influenced by climatic oscillations of the quaternary. competing hypotheses for the species' population history were derived from patterns of mitochondrial (mtdna) structure and a bioclimatic envelope model (bem). hypotheses invoked (1) sequential isolation of regional popu ... | 2011 | 21729045 |
| phenological variation in annual timing of hibernation and breeding in nearby populations of arctic ground squirrels. | ecologists need an empirical understanding of physiological and behavioural adjustments that animals can make in response to seasonal and long-term variations in environmental conditions. because many species experience trade-offs between timing and duration of one seasonal event versus another and because interacting species may also shift phenologies at different rates, it is possible that, in aggregate, phenological shifts could result in mismatches that disrupt ecological communities. we inv ... | 2011 | 21177687 |
| energetics of arousal episodes in hibernating arctic ground squirrels. | arctic ground squirrels overwintering in northern alaska experience average soil temperature of -10 degrees c. to examine energetic costs of arousing from hibernation under arctic compared to temperate conditions, captive ground squirrels were maintained in ambient temperatures (t(a)) of 2, -5 and -12 degrees c. rates of oxygen consumption and carbon dioxide production were used to estimate metabolic rate and fuel use during the three phases of arousal episodes: rewarming, euthermia, and recooli ... | 2009 | 19277682 |