Over-Winter Weight Loss by Richardson's Ground Squirrels in Relation to Sexual Differences in Mating Effort

1990 ◽  
Vol 71 (4) ◽  
pp. 489-499 ◽  
Author(s):  
G. R. Michener ◽  
L. Locklear
Keyword(s):  
Weight Loss ◽  
Ground Squirrels ◽  
Sexual Differences ◽  
Mating Effort

Influence of Hibernation on Survival Time and Weight Loss of X-Irradiated Ground Squirrels.

1953 ◽  
Vol 84 (2) ◽  
pp. 367-370 ◽  
Author(s):  
J. Doull ◽  
K. P. DuBois
Keyword(s):  
Weight Loss ◽  
Survival Time ◽  
Ground Squirrels

Sexual differences in over-winter torpor patterns of Richardson's ground squirrels in natural hibernacula

Oecologia ◽  
1992 ◽  
Vol 89 (3) ◽  
pp. 397-406 ◽  
Author(s):  
Gail R. Michener
Keyword(s):  
Ground Squirrels ◽  
Sexual Differences

Seasonal patterns and sexual differences in the feeding ecology of arctic ground squirrels (Spermophilus parryii plesius)

1985 ◽  
Vol 63 (6) ◽  
pp. 1298-1301 ◽  
Author(s):  
Ian G. McLean
Keyword(s):  
Feeding Ecology ◽  
Ground Squirrels ◽  
Sexual Differences ◽  
Seasonal Patterns ◽  
Spermophilus Parryii ◽  
Feeding Sites ◽  
Arctic Ground Squirrels ◽  
Selection Of

Arctic ground squirrels (Spermophilus parryii plesius) were studied in southwestern Yukon during the summers of 1977, 1978, and 1979. Samples of feces were collected from every adult captured every 2 weeks in 1978. Legumes were predominant in the diet until the fall, when squirrels switched to Artemisia. Females switched to Artemisia 1 month earlier than males, which correlates with the females' earlier entry into hibernation. Low abundance of legumes in areas in which squirrels preferred to feed indicated that squirrels fed selectively, although proximity of burrows also influenced selection of feeding sites.

Effect of age and parity on weight gain and entry into hibernation in Richardson's ground squirrels

1978 ◽  
Vol 56 (12) ◽  
pp. 2573-2577 ◽  
Author(s):  
Gail R. Michener
Keyword(s):  
Weight Loss ◽  
Weight Gain ◽  
Survival Rate ◽  
Weight Maintenance ◽  
Ground Squirrels ◽  
Winter Survival ◽  
Delayed Entry ◽  
Spermophilus Richardsonii ◽  
Southern Alberta ◽  
Effect Of Age

Weight gain and time of entry into hibernation were recorded for nonparous yearling, parous yearling, and parous 3-year-old Spermophilus richardsonii in southern Alberta in 1977. Nonparous squirrels steadily gained weight over the 12-week period between emergence from hibernation and immergence into hibernation. The weight pattern of parous squirrels exhibited a sub-cycle of weight gain, weight loss, and weight maintenance associated with pregnancy, parturition, and lactation resulting in delayed attainment of prehibernation peak weights and delayed entry into hibernation. There was no difference in time of emergence of parous and nonparous females in the subsequent spring. Age affected rates of post lactation weight gain such that the oldest mothers remained active longest but attained the lowest prehibernation weights. Oldest mothers had the lowest over-winter survival rate.

Sexual differences in weight loss upon eclosion are related to life history strategy in Lepidoptera

2011 ◽  
Vol 57 (6) ◽  
pp. 712-722 ◽  
Author(s):  
Freerk Molleman ◽  
Juhan Javoiš ◽  
Toomas Esperk ◽  
Tiit Teder ◽  
Robert B. Davis ◽  
...  
Keyword(s):  
Weight Loss ◽  
Life History ◽  
Life History Strategy ◽  
Sexual Differences

Sexual Differences in Body Weight Patterns of Richardson's Ground Squirrels during the Breeding Season

1984 ◽  
Vol 65 (1) ◽  
pp. 59-66 ◽  
Author(s):  
G. R. Michener
Keyword(s):  
Body Weight ◽  
Breeding Season ◽  
Ground Squirrels ◽  
Sexual Differences

Sexual differences in interyear survival and life-span of Richardson's ground squirrels

1989 ◽  
Vol 67 (7) ◽  
pp. 1827-1831 ◽  
Author(s):  
Gail R. Michener
Keyword(s):  
Sex Ratio ◽  
Life Span ◽  
Older Adult ◽  
Litter Size ◽  
Ground Squirrels ◽  
Sexual Differences ◽  
Maximum Life Span ◽  
Southern Alberta ◽  
Males And Females ◽  
Size At Birth

Although equal numbers of males and females were weaned in a population of Richardson's ground squirrels studied in southern Alberta, interyear survival was lower for males than for females in each year of life. Consequently, the sex ratio was biased toward females in both the yearling and older adult cohorts (overall ≤ 23 males per 100 females), and maximum life-span of males was 4 years, whereas that of females was 6 years. Compared with several other species of Spermophilus, Richardson's ground squirrels have a larger litter size at birth and a shorter life-span.

Adipose tissue dynamics during cyclic weight loss and weight gain of ground squirrels

1989 ◽  
Vol 256 (6) ◽  
pp. R1286-R1292 ◽  
Author(s):  
J. Dark ◽  
J. S. Stern ◽  
I. Zucker
Keyword(s):  
Weight Loss ◽  
Cell Size ◽  
Body Mass ◽  
Total Lipid ◽  
Subcutaneous Fat ◽  
Ground Squirrels ◽  
Fat Cell ◽  
Fat Depots ◽  
Fat Cell Size ◽  
Second Peak

Ad libitum fed golden-mantled ground squirrels undergo marked annual fluctuations in body mass; during the first cycle, peak and trough masses were approximately 291 and approximately 192 g, respectively. Peak masses were significantly higher (9%) during the second than the first cycle, reflecting a 15% increase in fat-free dry mass and a 12% increase in lipid reserves. The reduction in body mass during the weight loss phase was almost entirely due to an 84% decrease in total lipid reserves and reflected a decrease in adipocyte size but not number. All measured fat depots decreased at similar rates, and there was no evidence of preferential utilization or sparing of individual depots. Fat cell size decreased progressively in each depot during the transition from peak to trough masses and did not vary among the several depots at any stage of annual cycle. Adipocyte number increased in parametrial and retroperitoneal depots but not in the subcutaneous fat between the first and second body mass peaks; fat cell size in these two depots decreased by 28 and 20%, respectively, from the first to the second peak in body mass. Reduced lipid filling of adipocytes at the second peak mass, concomitant with adipocyte hyperplasia, suggests that total lipid mass, not simply fat cell size, is regulated during the annual body mass cycle. Maturation of the subcutaneous fat depot before the initial entry into hibernation may be adaptive in providing insulation during dormancy.

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