Circannual cycles in golden-mantled ground squirrels: Experiments with food deprivation and effects of temperature on periodicity

1980 ◽  
Vol 136 (4) ◽  
pp. 355-360 ◽  
Author(s):  
N. Mrosovsky
Keyword(s):  
Food Deprivation ◽  
Ground Squirrels ◽  
Circannual Cycles ◽  
Effects Of Temperature

Accelerated circannual cycles in ground squirrels, Spermophilus richardsonii, kept in constant conditions

1983 ◽  
Vol 61 (8) ◽  
pp. 1765-1770 ◽  
Author(s):  
Roman B. Melnyk
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Food Intake ◽  
Ground Squirrels ◽  
Food Utilization ◽  
Metabolic Processes ◽  
Reproductive Condition ◽  
Spermophilus Richardsonii ◽  
Upper Limit ◽  
Circannual Cycles

Six- to 8-month cycles of food intake, body weight, moult and reproductive condition in captive Richardson's ground squirrels (Spermophilus richardsonii) kept in 12 h light: 12 h dark and 23 ± 3 °C for over a year are described. A decrease in efficiency of food utilization towards the end of the weight gain period may be associated with metabolic processes which determine an upper limit for body weight. The advantages of this species as a model for the study of spontaneous obesity are discussed.

Meal patterns and food intakes of ground squirrels during circannual cycles

Appetite ◽  
1986 ◽  
Vol 7 (2) ◽  
pp. 163-175 ◽  
Author(s):  
N. Mrosovsky ◽  
Michael Boshes
Keyword(s):  
Ground Squirrels ◽  
Meal Patterns ◽  
Circannual Cycles

Circannual cycles of molt in ground squirrels

1982 ◽  
Vol 60 (12) ◽  
pp. 3227-3231 ◽  
Author(s):  
Janet E. Joy ◽  
N. Mrosovsky
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Ground Squirrels ◽  
The Body ◽  
Spermophilus Tridecemlineatus ◽  
Laboratory Conditions ◽  
Circannual Cycles ◽  
Later Phase

Molt was studied in thirteen-lined ground squirrels (Spermophilus tridecemlineatus) from Kansas and Michigan. In constant laboratory conditions molt showed circannual cycles and generally occurred during the weight gain phase of the circannual body weight cycle. Molt in the Kansas ground squirrels began at a slightly later phase of the body weight cycle and ended at an earlier phase of the body weight cycle than in the Michigan ground squirrels. The relative portions of the body weight cycle spent molting was close to 35% in both populations. Molt is not dependent on the circannual body weight cycle, but is under control of the same circannual system.

Effects of temperature on the duration of arousal episodes during hibernation

1982 ◽  
Vol 52 (1) ◽  
pp. 216-220 ◽  
Author(s):  
A. R. French
Keyword(s):  
Environmental Temperature ◽  
Ground Squirrels ◽  
Adult Males ◽  
Body Temperatures ◽  
High Body ◽  
Different Temperatures ◽  
Effects Of Temperature ◽  
Spermophilus Beldingi ◽  
Chemical Imbalance ◽  
Large Adult

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 S. beldingi was correlated with body size. Large adult males remained at high body temperatures longer than adult females, which in turn remained euthermic longer than small juveniles. In addition, these squirrels spent less time at high body temperatures following bouts of torpor that were interrupted prematurely by environmental disturbances. These results are consistent with an amplify the theory that arousals are initiated by, and necessary for the elimination of, some chemical imbalance, which develops while hibernators metabolize at low body temperatures.

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