scholarly journals The secret life of ground squirrels: accelerometry reveals sex-dependent plasticity in above-ground activity

2016 ◽  
Vol 3 (9) ◽  
pp. 160404 ◽  
Author(s):  
Cory T. Williams ◽  
Kathryn Wilsterman ◽  
Victor Zhang ◽  
Jeanette Moore ◽  
Brian M. Barnes ◽  
...  
Keyword(s):  
Activity Patterns ◽  
Ground Squirrels ◽  
Thermal Exchange ◽  
Active Season ◽  
Below Ground ◽  
Overall Dynamic Body Acceleration ◽  
Second Year ◽  
Arctic Ground Squirrels ◽  
Daily Activity Patterns ◽  
Variance Explained

The sexes differ in how and when they allocate energy towards reproduction, but how this influences phenotypic plasticity in daily activity patterns is unclear. Here, we use collar-mounted light loggers and triaxial accelerometers to examine factors that affect time spent above ground and overall dynamic body acceleration (ODBA), an index of activity-specific energy expenditure, across the active season of free-living, semi-fossorial arctic ground squirrels ( Urocitellus parryii ). We found high day-to-day variability in time spent above ground and ODBA with most of the variance explained by environmental conditions known to affect thermal exchange. In both years, females spent more time below ground compared with males during parturition and early lactation; however, this difference was fourfold larger in the second year, possibly, because females were in better body condition. Daily ODBA positively correlated with time spent above ground in both sexes, but females were more active per unit time above ground. Consequently, daily ODBA did not differ between the sexes when females were early in lactation, even though females were above ground three to six fewer hours each day. Further, on top of having the additional burden of milk production, ODBA data indicate females also had fragmented rest patterns and were more active during late lactation. Our results indicate that sex differences in reproductive requirements can have a substantial influence on activity patterns, but the size of this effect may be dependent on capital resources accrued during gestation.

scholarly journals BODY TEMPERATURE AND ACTIVITY PATTERNS IN FREE-LIVING ARCTIC GROUND SQUIRRELS

2005 ◽  
Vol 86 (2) ◽  
pp. 314-322 ◽  
Author(s):  
Ryan A. Long ◽  
Timothy J. Martin ◽  
Brian M. Barnes
Keyword(s):  
Body Temperature ◽  
Activity Patterns ◽  
Ground Squirrels ◽  
Free Living ◽  
Arctic Ground Squirrels

scholarly journals Temporal Dynamics of the Cecal Gut Microbiota of Juvenile Arctic Ground Squirrels: a Strong Litter Effect across the First Active Season

2014 ◽  
Vol 80 (14) ◽  
pp. 4260-4268 ◽  
Author(s):  
Timothy J. Stevenson ◽  
C. Loren Buck ◽  
Khrystyne N. Duddleston
Keyword(s):  
Microbial Community ◽  
Microbial Diversity ◽  
Short Chain Fatty Acid ◽  
Chain Fatty Acid ◽  
Ground Squirrels ◽  
Short Chain ◽  
Active Season ◽  
The Mean ◽  
Arctic Ground Squirrels ◽  
Gut Microbial Community

ABSTRACTArctic ground squirrels (Urocitellus parryii) are active for a scant 3 to 5 months of the year. During the active season, adult squirrels compete for mates, reproduce, and fatten in preparation for hibernation, while juvenile squirrels, weaned in early July, must grow and acquire sufficient fat to survive their first hibernation season. During hibernation, the gut microbial community is altered in diversity, abundance, and activity. To date, no studies have examined the gut microbiota of hibernators across the truncated active season. We characterized trends in diversity (454 pyrosequencing), density (flow cytometry), viability (flow cytometry), and metabolism (short-chain fatty acid analysis) of the gut microbial community of juvenile arctic ground squirrels across their first active season at weaning and at 4, 6, 8, and 10 weeks postweaning. At 8 weeks postweaning, the mean bacterial density was significantly higher than that at weaning, and the mean percentage of live bacteria was significantly higher than that at either weaning or 4 weeks postweaning. No significant differences in microbial diversity, total short-chain fatty acid concentrations, or molar proportions of individual short-chain fatty acids were observed among sample periods. The level of variability in gut microbial diversity among squirrels was high across the active season but was most similar among littermates, except at weaning, indicating strong maternal or genetic influences across development. Our results indicate that genetic or maternal influences exert profound effects on the gut microbial community of juvenile arctic ground squirrels. We did not find a correlation between host adiposity and gut microbial diversity during prehibernation fattening, likely due to a high level of variability among squirrels.

scholarly journals Daily body temperature rhythms persist under the midnight sun but are absent during hibernation in free-living arctic ground squirrels

2011 ◽  
Vol 8 (1) ◽  
pp. 31-34 ◽  
Author(s):  
Cory T. Williams ◽  
Brian M. Barnes ◽  
C. Loren Buck
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Ground Squirrels ◽  
The Arctic ◽  
Constant Light ◽  
Polar Regions ◽  
Free Living ◽  
Active Season ◽  
Temperature Rhythms ◽  
Arctic Ground Squirrels

In indigenous arctic reindeer and ptarmigan, circadian rhythms are not expressed during the constant light of summer or constant dark of winter, and it has been hypothesized that a seasonal absence of circadian rhythms is common to all vertebrate residents of polar regions. Here, we show that, while free-living arctic ground squirrels do not express circadian rhythms during the heterothermic and pre-emergent euthermic intervals of hibernation, they display entrained daily rhythms of body temperature ( T b ) throughout their active season, which includes six weeks of constant sun. In winter, ground squirrels are arrhythmic and regulate core body temperatures to within ±0.2°C for up to 18 days during steady-state torpor. In spring, after the use of torpor ends, male but not female ground squirrels, resume euthermic levels of T b in their dark burrows but remain arrhythmic for up to 27 days. However, once activity on the surface begins, both sexes exhibit robust 24 h cycles of body temperature. We suggest that persistence of nycthemeral rhythms through the polar summer enables ground squirrels to minimize thermoregulatory costs. However, the environmental cues (zeitgebers) used to entrain rhythms during the constant light of the arctic summer in these semi-fossorial rodents are unknown.

Plasticity and repeatability of activity patterns in free-living Arctic ground squirrels

2020 ◽  
Vol 169 ◽  
pp. 81-91
Author(s):  
Helen E. Chmura ◽  
Victor Y. Zhang ◽  
Sara M. Wilbur ◽  
Brian M. Barnes ◽  
C. Loren Buck ◽  
...  
Keyword(s):  
Activity Patterns ◽  
Ground Squirrels ◽  
Free Living ◽  
Arctic Ground Squirrels

Seasonal changes in body composition of the arctic ground squirrel, Citellus undulatus

1976 ◽  
Vol 54 (1) ◽  
pp. 74-78 ◽  
Author(s):  
William Galster ◽  
Peter Morrison
Keyword(s):  
Seasonal Changes ◽  
Ground Squirrel ◽  
Significant Loss ◽  
Ground Squirrels ◽  
The Arctic ◽  
Average Weight ◽  
Active Season ◽  
Loss Of Weight ◽  
Glucose Synthesis ◽  
Arctic Ground Squirrels

The depletion or accumulation of body reserves is followed in terms of the weight and proportion of lipid, protein, water, and minerals in arctic ground squirrels during the entry, deep, and emergent phases of the hibernation season and after the reproductive phase of the active season. Average weight increased slowly through the summer, from a minimum of 346 g, until mid-August when 190 g accumulated in 3 weeks to be used subsequently during the 220-day hibernation season beginning in mid-September. During hibernation, the 325-g loss in weight represents 62% lipid, 26% water, 9% protein, and 2% mineral. Fat in lipid provides most of the energy but insufficient amounts of carbon for glucose synthesis during hibernation. However, protein provides an adequate gluconeogenic reserve. Significant loss of mineral indicates that skeletal reserves of calcium are important during hibernation. After hibernation, continued loss of weight by females indicates further utilization of reserves during gestation and nursing.

Patterns of hibernation in the arctic ground squirrel

1975 ◽  
Vol 53 (9) ◽  
pp. 1345-1355 ◽  
Author(s):  
Peter Morrison ◽  
William Galster
Keyword(s):  
Annual Cycle ◽  
Ground Squirrel ◽  
Ground Squirrels ◽  
The Arctic ◽  
Light Cycle ◽  
Arctic Ground Squirrel ◽  
Active Season ◽  
Cyclic Patterns ◽  
Arctic Ground Squirrels ◽  
Normal Light

Cyclic patterns were defined in subspecies of arctic ground squirrels (Citellus undulatus) from the Brooks and Alaskan Ranges. In the annual cycle a heterothermal (hibernation) season with entry, maintenance, and emergence stages was distinguished from a homeothermal (active) season with reproductive, recovery/growth, maintenance, and fattening stages. The heterothermal season consisted of a series of short hibernation cycles in which heterothermal (hibernation) periods with reentry, refractory, and irritable phases were distinguished from homeothermal (active) periods with arousal, maintenance, and preparation phases. Squirrels in which exposure to darkness at 5 °C was delayed (Nov. vs. Sept.) showed a lesser response but emerged synchronously with the normal group. Entry was attenuated with a normal light cycle at 5 °C (8 vs. 3 weeks). Juveniles showed a 2- to 4-week delay in entry as compared to adults.

Seasonal Variation in Daily Activity Patterns of Free-Ranging European Ground Squirrels (Spermophilus citellus)

2004 ◽  
Vol 21 (1) ◽  
pp. 57-71 ◽  
Author(s):  
Lammina G. Everts ◽  
Arjen M. Strijkstra ◽  
Roelof A. Hut ◽  
Ilse E. Hoffmann ◽  
Eva Millesi
Keyword(s):  
Seasonal Variation ◽  
Daily Activity ◽  
Activity Patterns ◽  
Ground Squirrels ◽  
Spermophilus Citellus ◽  
Free Ranging ◽  
Daily Activity Patterns

Evolutionary Dissipation of an Antisnake System: Differential Behavior By California and Arctic Ground Squirrels in Above- and Below-Ground Contexts

Behaviour ◽  
1990 ◽  
Vol 112 (3-4) ◽  
pp. 246-268 ◽  
Author(s):  
Ronald O. Goldthwaite ◽  
Donald H. Owings ◽  
Richard G. Coss
Keyword(s):  
Ground Squirrels ◽  
Spermophilus Beecheyi ◽  
Motor Patterns ◽  
Norway Rat ◽  
Spermophilus Parryii ◽  
Differential Behavior ◽  
Pituophis Melanoleucus ◽  
Below Ground ◽  
Arctic Ground Squirrels ◽  
California Ground Squirrels

AbstractArctic ground squirrels (Spermophilus parryii ablusus) have been free from snake predation for about 3 million years. To evaluate the effects of this prolonged relaxation of natural selection, lab-born Arctic ground squirrels were compared to snake-inexperienced California ground squirrels (Spermophilus beecheyi fisheri) from a habitat where rattlesnake and gopher snake predation is intense. Their behavior was video taped during 10-min encounters with a Pacific gopher snake (Pituophis melanoleucus catenifer) in a seminatural above-ground setting and in an artificial burrow. In separate trials, a domesticated Norway rat was used as a control for the effects of encountering a novel animate object; this rat was enclosed in a slowly moving opaque nylon bag above ground but was allowed to move freely below ground. No evidence was found that, after prolonged relaxed selection from snakes, Arctic ground squirrels retained the specialized behavioral antisnake defenses evident in California ground squirrels. Although we originally hypothesized that the more constrained burrow context might limit the evolutionary dissipation of behavioral antisnake defenses, we found no evidence of a more intact system in Arctic squirrels below than above ground. Arctic squirrels used many of the same general kinds of motor patterns as California squirrels, but in ways that failed to differentiate the gopher snake from the rat in either above- or below-ground contexts. In contrast, the California squirrels tail flagged only in the presence of the snake above ground and differentially applied substrate-throwing at the snake and rat burrow intruders, harassing the snake more than twice as much as the rat. Above ground, California ground squirrels were more conservative toward both adversaries than Arctic ground squirrels were, keeping their distance and therefore experiencing fewer noxious consequences, such as snake strikes. However, this result was context dependent. Below ground, California ground squirrels were more willing than Arctic ground squirrels to approach and harass both burrow intruders. Although repeated striking evoked occasional snake-directed substrate throwing above ground, Arctic ground squirrels never threw substrate at the snake in the burrow. In comparison with California ground squirrels, Arctic ground squirrels appear to enter their first gopher snake encounter with both a much lower assessment of the risk involved and less clearly defined knowledge about how to deal with these risks. We conclude that 3 million years of genetic drift has altered the cognitive system structuring the meaning of snakes to Arctic ground squirrels in various settings.

scholarly journals Seasonal changes in glucocorticoid and testosterone concentrations in free-living arctic ground squirrels from the boreal forest of the Yukon

2001 ◽  
Vol 79 (1) ◽  
pp. 49-58 ◽  
Author(s):  
Rudy Boonstra ◽  
Anne H Hubbs ◽  
Eileen A Lacey ◽  
Carolyn J McColl
Keyword(s):  
Binding Capacity ◽  
Ground Squirrels ◽  
Base Line ◽  
Adult Males ◽  
Free Living ◽  
Active Season ◽  
Spermophilus Parryii ◽  
Free Cortisol ◽  
Arctic Ground Squirrels ◽  
Juvenile Males

We examined how glucocorticoid and testosterone concentrations changed from spring to summer by livetrapping free-living populations of arctic ground squirrels (Spermophilus parryii). The primary glucocorticoid was found to be cortisol, with corticosterone below measurable concentrations in most individuals. Livetrapping elicited a strong stress response in both sexes: breeding males and females trapped in spring had free cortisol concentrations 4 and 34 times, respectively, those of base-line animals. The maximum corticosteroid-binding capacity (MCBC) was unaffected by trapping and was about 3 times higher in breeding females than in breeding males. Over the active season, MCBC values were lowest in all male classes (juveniles, nonreproductive adults, and reproductive adults), being less than half those in all female classes; pregnant females had values approximately twice those of juvenile females. However, free cortisol concentrations were similar in all female classes and in juvenile males and about half those in adult males. Livetrapping increased testosterone concentrations in males over those found in samples from base-line males, and testosterone concentrations did not affect MCBC values. Testosterone concentrations in livetrapped animals differed significantly among male classes, with nonreproductive males maintaining concentrations 64% of those in breeding males and 10 times those in juveniles.

scholarly journals Activity patterns of the soprano pipistrelle Pipistrellus pygmaeus throughout the year in southern Norway

BMC Zoology ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Karl Frafjord
Keyword(s):  
Activity Patterns ◽  
Late Summer ◽  
Active Season ◽  
Male Song ◽  
Oceanic Climate ◽  
Social Calls ◽  
Southern Norway ◽  
Winter Hibernation ◽  
Small Valley ◽  
Made In

Abstract Background Most temperate bats are regular hibernators in the winter. Knowledge about the length of their active season and how they adjust their nightly activity throughout the season, is critical to conservation. The characteristics of these are likely to vary with climate as well as latitude. This study investigated the flight activity of the soprano pipistrelle Pipistrellus pygmaeus in Frafjord, a small valley in the south-western corner of Norway (58° 50′N 6° 18′E) with an oceanic climate. Results Activity was recorded with an ultrasound recorder throughout April 2018 to June 2019 at one site, with supplemental recordings in March to June 2020, i.e., covering all months of the year. Recordings at other nearby sites were made in the summers (June–August) of 2016, 2017, 2019 and 2020, as well as some of the last days in December 2019 to the first days of January 2020. Overall, soprano pipistrelles were recorded flying in all months of the year, but very few in December–March. Regular activity was recorded from late April or early May until late October, and some recordings were also made in November. The highest numbers of recordings were made in August and September. Social calls, i.e. male song flights, were recorded from April to November, with the vast majority in August and September. Nearly all recordings were made between sunset and sunrise. Conclusions The soprano pipistrelle in this region showed regular activity through 6–7 months of the year. It adjusted its activity to the changing night length throughout the year, closely following sunset and sunrise. It was rarely recorded flying before sunset and almost never after sunrise. Most activity was recorded in the middle of the night, and social calls also followed this trend closely. Harems in late summer and autumn were confirmed in a bat box, which was also used for winter hibernation.

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