Sarcocystis campestris from Naturally Infected 13-Lined Ground Squirrels, Spermophilus tridecemlineatus tridecemlineatus, from Nebraska

Small hibernating mammals show regular oscillations in their heart rate and body temperature throughout the winter. Long periods of torpor are abruptly interrupted by arousals with heart rates that rapidly increase from 5 beats/min to over 400 beats/min and body temperatures that increase by ∼30°C only to drop back into the hypothermic torpid state within hours. Surgically implanted transmitters were used to obtain high-resolution electrocardiogram and body temperature data from hibernating thirteen-lined ground squirrels ( Spermophilus tridecemlineatus ). These data were used to construct a model of the circulatory system to gain greater understanding of these rapid and extreme changes in physiology. Our model provides estimates of metabolic rates during the torpor-arousal cycles in different model compartments that would be difficult to measure directly. In the compartment that models the more metabolically active tissues and organs (heart, brain, liver, and brown adipose tissue) the peak metabolic rate occurs at a core body temperature of 19°C approximately midway through an arousal. The peak metabolic rate of the active tissues is nine times the normothermic rate after the arousal is complete. For the overall metabolic rate in all tissues, the peak-to-resting ratio is five. This value is high for a rodent, which provides evidence for the hypothesis that the arousal from torpor is limited by the capabilities of the cardiovascular system.

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Expression of Nrf2 and its downstream gene targets in hibernating 13-lined ground squirrels, Spermophilus tridecemlineatus

Molecular and Cellular Biochemistry ◽

10.1007/s11010-008-9727-3 ◽

2008 ◽

Vol 312 (1-2) ◽

pp. 121-129 ◽

Cited By ~ 51

Author(s):

Pier Jr Morin ◽

Zhouli Ni ◽

David C. McMullen ◽

Kenneth B. Storey

Keyword(s):

Ground Squirrels ◽

Spermophilus Tridecemlineatus

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Changes in Thermal Conductivity of the Integument in Nonhibernating 13-Lined Ground Squirrels (Spermophilus tridecemlineatus) in Relation to Ambient Temperature

Physiological Zoology ◽

10.1086/physzool.43.2.30155519 ◽

1970 ◽

Vol 43 (2) ◽

pp. 98-108 ◽

Cited By ~ 3

Author(s):

Thomas F. Ogle

Keyword(s):

Thermal Conductivity ◽

Ambient Temperature ◽

Ground Squirrels ◽

Spermophilus Tridecemlineatus

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Antioxidant defense in hibernation: Cloning and expression of peroxiredoxins from hibernating ground squirrels, Spermophilus tridecemlineatus

Archives of Biochemistry and Biophysics ◽

10.1016/j.abb.2007.01.035 ◽

2007 ◽

Vol 461 (1) ◽

pp. 59-65 ◽

Cited By ~ 46

Author(s):

Pier Jr Morin ◽

Kenneth B. Storey

Keyword(s):

Antioxidant Defense ◽

Ground Squirrels ◽

Cloning And Expression ◽

Spermophilus Tridecemlineatus

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Helminth parasites of squirrels (Sciuridae) in Saskatchewan

Canadian Journal of Zoology ◽

10.1139/z80-280 ◽

1980 ◽

Vol 58 (11) ◽

pp. 2040-2050 ◽

Cited By ~ 8

Author(s):

Steven G. McGee

Keyword(s):

Ground Squirrels ◽

Tamiasciurus Hudsonicus ◽

Glaucomys Sabrinus ◽

Helminth Parasites ◽

Spermophilus Tridecemlineatus ◽

New Host ◽

Marmota Monax ◽

The Family ◽

Spermophilus Franklinii ◽

New Host Records

During the period March 1976 to November 1977, 377 mammals of the family Sciuridae (Rodentia) were collected in Saskatchewan and examined for helminths. Species and numbers of each were as follows: Spermophilus richardsonii (Sabine), 209; Spermophilus franklinii (Sabine), 46; Spermophilus tridecemlineatus (Mitchill), 31; Tamiasciurus hudsonicus (A. H. Howell), 64; Glaucomys sabrinus (Shaw), 12; Eutamias minimus (J. A. Allen), 11; and Marmota monax (Erxleben), 4.Ten species of cestodes, 2 species of trematodes, 11 species of nematodes, and 1 acanthocephalan were represented in the collections made. New host records and (or) geographic range extensions were indicated for 10 species of helminths.In addition to taxonomic considerations of the helminths, attention has been given to parasite–host relationships involving ground squirrels. In general, male Spermophilus spp. were significantly more commonly infected than were females, and older squirrels were significantly more commonly infected than were younger ones. However, adult squirrels did not have significantly more worms than did juveniles.

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