The squirrel that cried wolf: reliability detection by juvenile Richardson's ground squirrels ( Spermophilus richardsonii )

2001 ◽  
Vol 51 (1) ◽  
pp. 108-112 ◽  
Author(s):  
James Hare ◽  
Brent Atkins
Keyword(s):  
Ground Squirrels ◽  
Spermophilus Richardsonii

Effects of central injection of biogenic amines during arousal from hibernation

1979 ◽  
Vol 236 (3) ◽  
pp. R162-R167 ◽  
Author(s):  
J. D. Glass ◽  
L. C. Wang
Keyword(s):  
Ambient Temperature ◽  
Specific Heat ◽  
Biogenic Amines ◽  
Heat Production ◽  
Ground Squirrels ◽  
Spermophilus Richardsonii ◽  
Simultaneous Measurements ◽  
Apparent Specific Heat ◽  
Intracerebroventricular Injections ◽  
Made In

Simultaneous measurements of heat production (HP) and heat loss (HL) and brain and rectal temperatures were made in Richardon's ground squirrels (Spermophilus richardsonii) rewarming from hibernation at an ambient temperature of 6.0 +/- 0.5 degrees C. Calculations from HP and HL measurements from control animals showed that due to differential rewarming, there was a reduction of apparent specific heat of the animal to 0.59 cal/g. degrees C. This resulted in an energy saving of 30%. Three intracerebroventricular injections of 5-hydroxytryptamine (5-HT) of 56 microgram each at brain temperatures of 10, 20, and 30 degrees C caused initial suppression of HP and a greater overall HL, which resulted in a slower rate of arousal as compared to the controls. Injections of norepinephrine (NE) of 12.5 microgram each at similar brain temperatures caused a greater rate of HP, which resulted in a faster rate of arousal as compared to the controls. The respective actions of 5-HT and NE on thermoregulation during rewarming are similar to those in some euthermic hibernators and nonhibernating species. Our data indicated that these substances evoke thermoregulatory responses during arousal in much the same manner as during normothermia.

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.

Description of Sarcocystis campestris sp. n. (Protozoa: Sarcocystidae): a parasite of the badger Taxidea taxus with experimental transmission to the Richardson's ground squirrel, Spermophilus richardsonii

1983 ◽  
Vol 61 (2) ◽  
pp. 370-377 ◽  
Author(s):  
Richard J. Cawthorn ◽  
Gary A. Wobeser ◽  
Alvin A. Gajadhar
Keyword(s):  
Ground Squirrel ◽  
Prepatent Period ◽  
Ground Squirrels ◽  
Intermediate Hosts ◽  
Patent Period ◽  
Sporocyst Residuum ◽  
Experimental Transmission ◽  
Taxidea Taxus ◽  
Spermophilus Richardsonii ◽  
Large Round

Sarcocystis campestris sp. n. (Protozoa: Sarcocystidae) is an heteroxenous coccidium with badgers (Taxidea taxus) as natural and experimental definitive hosts and Richardson's ground squirrels (Spermophilus richardsonii) as experimental intermediate hosts. Free sporocysts (10.2 × 8.0 μm with a large, round sporocyst residuum consisting of a single refractile granule), obtained from intestinal scrapings of badgers (carcasses frozen 2 years at −20 °C), were orally administered to juvenile Richardson's ground squirrels. Acute fatal sarcocystosis developed in some squirrels at 11–13 days postinoculation (p.i.). Meronts (second generation) were present 9–12 days p.i. in the vascular endothelium of many tissues (especially the lungs). Cysts developed in skeletal muscle, contained metrocytes (7 × 5 μm) 30 days p.i., and beginning 46 days p.i., bradyzoites (12.0 × 3.5 μm) were present. Cysts were macroscopic as early as 258 days p.i. Squirrel carcasses containing cysts (76 days p.i.) of S. campestris sp. n. were fed to Sarcocystis-free badgers. The prepatent period was 9 days and the patent period at least 13 days. Both badgers were ill early in the patent period and passed unformed feces during the patent period. Free sporocysts were 10.2 × 8.0 μm and each had an elongate sporocyst residuum containing numerous small refractile granules.

scholarly journals Hepatocellular carcinoma in Richardson's ground squirrels(Spermophilus richardsonii): Evidence for association with hepatitis B–like virus infection

Hepatology ◽  
1991 ◽  
Vol 13 (6) ◽  
pp. 1215-1221 ◽  
Author(s):  
Bud C. Tennant ◽  
N. Mrosovsky ◽  
Kirsteen McLean ◽  
Paul J. Cote ◽  
Brent E. Korba ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Virus Infection ◽  
Hepatitis B ◽  
Ground Squirrels ◽  
Spermophilus Richardsonii

Killing technique of North American badgers preying on Richardson's ground squirrels

2001 ◽  
Vol 79 (11) ◽  
pp. 2109-2113 ◽  
Author(s):  
Gail R Michener ◽  
Andrew N Iwaniuk
Keyword(s):  
North American ◽  
Prey Size ◽  
Ground Squirrels ◽  
Thoracic Cavity ◽  
Internal Organs ◽  
Small Prey ◽  
Taxidea Taxus ◽  
Spermophilus Richardsonii ◽  
Southern Alberta

Carcasses of 13 Richardson's ground squirrels (Spermophilus richardsonii) cached during autumn by North American badgers (Taxidea taxus) in southern Alberta, Canada, were inspected to determine the capture and killing technique. Regardless of prey size (251–651 g) or torpor status (normothermic or torpid), badgers killed ground squirrels with a single grasping bite directed dorsally or laterally to the thorax. The canines and third upper incisors of badgers generally bruised the skin without puncturing it, but caused extensive hematomas on the thoracic musculature and penetrated between the ribs, with associated breakage of ribs and hemorrhaging in the thoracic cavity. Internal organs and bones other than ribs were usually not damaged. Thoracic bites, rather than nape or throat bites, are used by several mustelids, including North American badgers, when capturing small prey (<10% of the predator's mass).

Copulatory behaviour of Richardson's ground squirrels (Spermophilus richardsonii) in the wild

1982 ◽  
Vol 60 (11) ◽  
pp. 2953-2955 ◽  
Author(s):  
Lloyd S. Davis
Keyword(s):  
Ground Squirrels ◽  
Spermophilus Richardsonii ◽  
In The Wild ◽  
High Degree ◽  
Copulatory Behaviour

In this paper I give the first authenticated account of copulation occurring above ground in Richardson's ground squirrels. Copulation occurs in a dorso-ventral position with both animals lying on their sides, and is characterized by a high degree of agonism between the pair.

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