Circannual cycles in golden-mantled ground squirrels: Lengthening of period by low temperatures in the spring phase

1983 ◽  
Vol 150 (2) ◽  
pp. 233-238 ◽  
Author(s):  
J. E. Joy ◽  
N. Mrosovsky
Keyword(s):  
Low Temperatures ◽  
Ground Squirrels ◽  
Circannual Cycles

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

scholarly journals Pulmonary Surfactant Membranes of Hibernating Ground Squirrels Possess Increased Fluidity but are Capable of Maintaining an Ordered Membrane Structure at Low Temperatures

2011 ◽  
Vol 100 (3) ◽  
pp. 628a
Author(s):  
Lakshmi N.M. Suri ◽  
Lynda McCaig ◽  
Victoria Picardi ◽  
Ruud Veldhuizen ◽  
James Staples ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Pulmonary Surfactant ◽  
Membrane Structure ◽  
Ground Squirrels

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.

Myocardial metabolic and electrical properties of rabbits and ground squirrels at low temperatures

1959 ◽  
Vol 197 (2) ◽  
pp. 494-498 ◽  
Author(s):  
Benjamin G. Covino ◽  
John P. Hannon
Keyword(s):  
Low Temperatures ◽  
Ground Squirrel ◽  
Coronary Flow ◽  
Rabbit Heart ◽  
Ground Squirrels ◽  
The Body ◽  
Perfusion Fluid ◽  
Flow Rates ◽  
Ventricular Tissue

When perfused in vitro with Krebs-Henseleit solution both rabbit and arctic squirrel hearts exhibit similar contraction rates in a temperature range of 35°–25°C. Below 25° the rabbit heart was more susceptible to the present effect of cold. A reduction in temperature produced a much more pronounced depression in diastolic ventricular excitability in the rabbit than in the ground squirrel. At any given temperature, both species had quite similar in vitro coronary flow rates. As the perfusion fluid was cooled, however, flow rates of both species were markedly lowered. Ventricular tissue removed from rabbits with rectal temperatures of 15°C showed that a conversion of ATP to ADP had occurred. Lowering of the body temperature to 15°C in squirrels had no effect on ventricular ATP levels. At both normal and hypothermic temperatures, the total ventricular nucleotide content was much higher in squirrels than in rabbits. At 38° and at 15° squirrels exhibited a higher glutamic but a lower ß-hydroxybutyric, malic and succinic oxidase activity than rabbits.

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