Camp.
Biochem.
Physiol.
Vol.
IOIA, No. 4,
pp.
853-855,
0300-9629/92
1992
Q 1992
Printed in Great Britain
$5.00
+ 0.00
PergamonPressplc
THE EFFECTS OF DIETARY DEPRIVATION ON BODY TEMPERATURE AND OXYGEN CONSUMPTION IN BLACK-TAILED PRAIRIE DOGS (CYNOMYS LUDOVICIANUS) Northwest College,
M. WALLACE E. W. West 6th Powell, WY U.S.A. Telephone, University Montana, Missoula, 59812, U.S.A.
754-5569;
(Received 30 Jury 1991)
Abstract-l. Body temperature (Tb) and oxygen consumption (VO,) were compared between fed (Control), food and water deprived (FWD), and water deprived (WD) black-tailed prairie dogs, in the month of January. 2. Mean X’,of Control black-tailed prairie dogs (36.2”C)was significantly different from FWD (33.4”C) and WD (30.4”C) black-tailed prairie dogs. 3. VOz was not significantly different between FWD and Control black-tailed prairie dogs (4.4 and 4.0 ml O,/kg/hr, respectively), while VO, was significantly different between WD and Control animals (2.9 and 4.0 ml O,/kg/hr, respectively). 4. These findings are discussed as possible mechanisms for conserving body water.
INTRODUCTION
Black-tailed prairie dogs (Cyno~ys ~~~#vic~ffnus) are well-adapted to xeric environments. Reinking et al. (1977) found that black-tailed prairie dogs exhibit heat stress adaptations when exposed to high ambient temperatures: heat storage increased and oxygen consumption and evaporative water loss decreased. Pfeiffer et al. (1979) found that black-tailed prairie dogs maintained normal blood composition after prolonged starvation, with neither hypoglycemia nor ketosis resulting from deprivation of food and water. Respiratory exchange ratios are reduced in black-tailed prairie dogs when fasted (Pfeiffer et nl. 1979; Wallace et al., 1984) indicating that these animals metabolize primarily fats when subjected to this stress. Urea hydrolysis occurs in black-tailed prairie dogs and apparently increases in starved animals (Wallace et al., 1984). These physiological adaptations may reduce water loss. White-tailed prairie dogs (Cynomys leucurus) are known to be obligate hibe~ators (Tileston and Lechleitner, 1966; Hoogland, 1981; Bakko and Nahorniak, 1986; Harlow and Menkens, 1986). Although black-tailed prairie dogs are not considered true hibernators, they have been reported to enter torpor. Anthony (1955) observed what he referred to as “cold narcosis” in black-tailed prairie dogs. Hamilton and Pfeiffer (1977) found that black-tailed prairie dogs maintained at an ambient temperature of 6”C, had T,, ranging from 8 to 13°C. Harlow and Menkens (1986) observed bouts of torpor in laboratory black-tailed prairie dogs kept at 7°C. Fluctuations in r, of these animals have been reported diurnally (Bakko et al., 1988; Reinking et ai., 1977), as well as seasonally (Bakko et al., 1988). Thomas and Riedesel (1975) suggested that black-tailed prairie dogs are capable of hibernation, based on the results of ECG’s performed on perfused hearts at
10°C. Some authors have suggested that the lack of hibernation in black-tailed prairie dogs may contribute to the high degree of sociality in these communal animals (Tileston and Lechleitner, 1966; Michener, 1983). White-tailed prairie dogs have been observed entering periods of summer estivation while blacktailed prairie dogs remain active all summer (Tileston and Lechleitner 1966). It is the purpose of this study to determine the effects of dietary deprivations on T, and VO, in a laboratory colony of black-tailed prairie dogs. MATERIALS AND METHODS Twenty black-tailed prairie dogs, captured at the C. M. RusseIl Wildlife Refuge in eastern Montana, were used in this study. These animals were caged singly and fed three Wayne lab blocks, i carrot, and i head of lettuce each day. Free water was not provided. Normal photoperiod was maintained with natural lighting. Animals were assigned to one of the following categories. Control: animals mainline as stated above; FWD: animals given no food or water; WD: animals deprived of their water source (carrots and lettuce) and provided with three lab blocks daily. Data collection started after 1-2 weeks of fasting. Prairie dogs were weighed to the nearest gram regularly, using a Torbal torsion balance. Body temperature During the experiment, deep rectal temperatures were taken regularly on prairie dogs, using a Yellow Springs tele-the~ometer (YSI Model 44TD) calibrated with a mercury thermometer traceable to the National Bureau of Standards. These measurements were taken between 1400 and 1600 hr.
During the month of January, VO, was measured using a flow-through, steady state system, according to Hill (1972). Observed and expected VO, values were calculated
GAMY M. WALLACEand E. W.
854
and allometrically standardized for body weight according to Reinking et al. (1977). Statistical procedures
One-sided Mann-Whitney T statistics compared r, between the Control and experimental groups. Expected VO, values were compared to observed VO, values using the sign test based on the binomial distribution. One-sided Mann-Whitney T statistics were calculated for VO, data between Control and experimental groups. RESULTS Body temperature
Table 1 shows body weight, Tb (“C), observed and expected VOZ (ml O,/kg/hr), and days fasted for Control, FWD, and WD black-tailed prairie dogs. Control black-tailed prairie dogs had a mean T, of 36.2”C, while FWD and WD animals had mean T, of 33.4 and 30.4”C, respectively. FWD and WD blacktailed prairie dogs had significantly lower Tb than Control animals (P < 0.05 and P < 0.005, respectively). Oxygen consumption Control black-tailed prairie dogs had observed mean VO1 of 4.0 ml O,/kg/hr with expected mean VOz of 4.4 ml O,/kg/hr. FWD and WD animals had observed mean VOr of 4.4 and 2.9 ml O,/kg/hr, respectively while FWD and WD animals had expected mean VOXof 4.8 and 4.4 ml O,/kg/hr, respectively. There was no significant difference between observed VOr of Control and FWD prairie dogs, P > 0.05; while WD black-tailed prairie dogs had significantly lower observed VO, than Control prairie dogs, P = 0.05. Fifteen out of 20 observed VOr values were lower than expected for animals of their body weight. The sign test comparing observed and expected VO, values showed that observed VOr (all groups combined) was significantly lower than expected, P = 0.02.
Table
Animal no. Control
mean (SD) FWD
mean (SD) WD
mean (SD1
3 4 11 12 23 5 7 IS I8 22 1 10 14 17 19 21 13
DISCUSSION
Black-tailed prairie dogs range from northern Mexico to southern Canada, through the semi-arid great plains of the United States (Harlow and Menkens, 1986). Despite these conditions, blacktailed prairie dogs withstand this stress and apparently proliferate (Merriam 1901). Unlike the white-tailed prairie dog that hibernates during winter in the field (Bakko and Nahorniak, 1986) and hibernates in the laboratory (Harlow and Menkens, 1986), black-tailed prairie dogs do not hibernate (Tileston and Lechleitner, 1966; Hoogland, 1981) although Thomas and Riedesel (1975) concluded on the basis of ECG results of perfused hearts kept at 10°C that black-tailed prairie dogs have the ability to hibernate. FWD and WD black-tailed prairie dogs of this study did enter periodic bouts of torpor. Harlow and Menkens (1986) concluded that black-tailed prairie dogs are not induced into a state of torpor simply through an interaction with environmental cues, which induce torpor in other animals. These authors stated that a combination of winter photoperiod, decrease in temperature, and food deprivation, however, does induce torpor in some black-tailed prairie dogs. FWD and WD black-tailed prairie dogs of this study reduced metabolism as indicated in the depressed V02 and Tb values when compared to Controls (Table 1). When comparing allometrically standardized VOZ levels among all black-tailed prairie dogs combined (Control, FWD and WD), observed values were significantly lower than expected, during the month of January. Bakko et al. (1988) observed significantly lower T, during the month of January in field black-tailed prairie dogs. Although these authors did not observe torpor in these animals, they did record Tb as low as 31°C. They suggested that lowered Tb results in energy and water savings. Rubsamen (1980) observed that the rock hyrax, a resident of semi-arid conditions, decreased VO, with concomitant decreases in evaporative water loss and
1. Body weight, body temperature Body weight (g) 1065 1182 1306 1226 1183 1195(101) 1127 1292 1066 1187 1024 1139(105) IOCIO 1004 1124 1430 1163 845 1007 1081(184)
(G, 35.0 36.5 36.4 36.0 37.0 36.2 (0.8) 36.0 35.4 25.6 35.2 34.9 33.4 (4.4) 33.0 25.5 32.9 30.3 21.4 29.0 34.6 30.4 (3.3)
PFEIFFER
and oxygen consumption
w observed (ml %I kg/hr)
vo, expected (ml 0,l kg/hr)
3.8 5.4 3.7 3.6 3.7 4.0 (0.8) 4.2 3.5 8.1 2.5 3.5 4.4 (2.2) 3.9 2.5 2.3 2.9 2.0 1.9 5.0 2.9(1.1)
4.0 4.3 4.7 4.8 4.4 4.4 (0.3) 4.7 5.2 4.7 5.0 4.5 4.8 (0.3) 4.3 4.2 4.4 5.2 4.6 3.8 4.3 4.4 (0.4)
Days fasted 0 0 0 0 0 0 I2
12 17 12 I2 13 (2) 9 9
9 9 9 8 (2)
Prairie dog T, and VO, Tb in response to water restriction. The lowered Tb decreased the need for heat dissipation through the evaporation of water, thus reducing water loss. Bakko et al. (1988) stated that lowered r, has adaptive potential for body water conservation by reducing evaporative water loss. WD black-tailed prairie dogs in this study had the lowest Tb and VOZ values of any group. It may be hypothesized that because WD animals were provided with a dry food source that was consumed in small amounts, these animals then produced metabolic waste products, necessitating increased urination, thereby putting themselves into a greater water stress than FWD animals. This could explain why WD animals had depressed Tb and VO, values below those of Control and FWD animals. Harlow and Menkens (1986) showed that the number of torpid black-tailed prairie dogs increased with the removal of water fr6m their diets. Harlow and Menkens (1986) stated that enhanced urea recycling capacity could provide black-tailed prairie dogs with an additional means to cope with water deprivation and decreased the need to engage in torpor until conditions become extreme. Wallace et al. (1984) showed that black-tailed prairie dogs did exhibit urea hydrolysis, and when comparing the ratio of relative urea hydrolysis to urea excretion in the urine between FWD and Control black-tailed prairie dogs, FWD animals apparently increased urea hydrolysis over that of Controls (2.6 and 1.8, respectively). Urea recycling provides an advantage of reducing the amount of urinary water loss needed to dilute and flush urea from the body (Hochachka and Somero, 1984) in light of the fact that black-tailed prairie dogs do not concentrate urine to the same level as do other arid-living species (Hamilton and Pfeiffer, 1976; Reinking et al., 1977). Reinking et al. (1977) stated that metabolic and temperature responses seem to play a major role in black-tailed prairie dog water balance. This study has shown that laboratory FWD and WD black-tailed prairie dogs decrease body temperature and oxygen consumption when compared to Control animals. Water restriction (WD regime) apparently accentuates these responses over that of FWD animals. Torpor was observed in some animals. These physiological responses to dietary deprivation provide black-tailed prairie dogs with a possible means to conserve body water when food and water are limited.
855 REFERENCES
Anthony A. (1955) Behavior patterns in a laboratory colony of prairie dogs, Cynomys ludovicianus. J. Mammal. 36, 69-78.
Bakko E. B., Porter W. P. and Wunder B. A. (1988) Body temperature patterns in black-tailed prairie dogs in the field. Can. J. Zool. 66, 1783-1789. Bakko E. B. and Nahorniak J. (1986) Torpor patterns in captive white-tailed prairie dog, Cynomys leucurus. 1. Mammal. 67, 516-578.
Hamilton J. D. and Pfeiffer E. W. (1977) Effects of cold exposure and dehydration on renal function in blacktailed prairie dogs. J. appl. Physiol. Resp. Environ. Exercise Physiot. 42, 295-299.
Harlow H. J. and Menkens G. E. Jr (1986) A comparison of hibernation in the black-tailed prairie dog, white-tailed prairie dog, and Wyoming ground squirrel. Can. J. Zool. 64, 793-796.
Hill R. W. (1972) Determination of oxygen consumption by use of the paramagnetic oxygen analyzer. J. appl. Physiol. 33, 261-263.
Hochachka P. W. and Somero G. N. (1984) Biochemical Adaptations. pp. 239-241. Princeton University Press, Princeton, NJ. Hoogland T. L. (1981) The evolution of coloniality in whitetailed orairie dogs and black-tailed orairie dogs (Cvnomvs leucurus and C.-ludovicianus). Ecology 62, 252-272. ’ Merriam C. H. (1901) The Prairie Dog of the Great Plains. pp. 257-270. Yearbook, U.S. Department of Agriculture. Michener G. R. (1983) Kin identification, matriarchies, and the evolution of sociality in ground-dwelling s&rids. In Recent Advances in the Study of Mammalian Behavior
(Edited by Eisenberg J. F. and Kleiman D. G.), No. 7. pp. 528-572. Spec. Publ. Am. Sot. Mammal. Pfeiffer E. W., Reinking L. N. and Hamilton J. D. (1979) Some effects of food and water deprivation on metabolism in black-tailed prairie dogs Cynomys ludovicianus. Comp. Biochem. Physiol. 63, 19-22.
Rubsamen K. and Kettembeil S. (1980) Effect of water restriction on oxygen uptake, evaporative water loss and body temperature of the rock hyrax. J. camp. Physiot. 138, 3 15-320.
Reinking L. N., Kilgore D. L., Fairbanks E. S. and Hamilton J. D. (1977) Temperature regulation in normothermic black-tailed prairie dogs, Cynomys ludovicianus. Comp. Biochem. Physiol. 5lA, 161-165. Tileston J. V. and Lechleitner R. R. (1966) Some comparisons of the black-tailed and white-tailed prairie dogs in north-central Colorado. Am. Midt. Nat. 75, 292-316. Thomas T. H. and Riedesel M. L. (1975) Evidence of hibernation in the black-tailed prairie dog Cynomys ludovicianus. Cryobiology 12, 559.
Wallace G. M., Fevold H. R. and Pfeiffer E. W. (1984) Urea hydrolysis in black-tailed prairie dogs (Cynomys ludovicianus). Comp. Biochem. Physiol. 78A, 219-283.
Biochem.
Physiol.
Vol.
IOIA, No. 4,
pp.
853-855,
0300-9629/92
1992
Q 1992
Printed in Great Britain
$5.00
+ 0.00
PergamonPressplc
THE EFFECTS OF DIETARY DEPRIVATION ON BODY TEMPERATURE AND OXYGEN CONSUMPTION IN BLACK-TAILED PRAIRIE DOGS (CYNOMYS LUDOVICIANUS) Northwest College,
M. WALLACE E. W. West 6th Powell, WY U.S.A. Telephone, University Montana, Missoula, 59812, U.S.A.
754-5569;
(Received 30 Jury 1991)
Abstract-l. Body temperature (Tb) and oxygen consumption (VO,) were compared between fed (Control), food and water deprived (FWD), and water deprived (WD) black-tailed prairie dogs, in the month of January. 2. Mean X’,of Control black-tailed prairie dogs (36.2”C)was significantly different from FWD (33.4”C) and WD (30.4”C) black-tailed prairie dogs. 3. VOz was not significantly different between FWD and Control black-tailed prairie dogs (4.4 and 4.0 ml O,/kg/hr, respectively), while VO, was significantly different between WD and Control animals (2.9 and 4.0 ml O,/kg/hr, respectively). 4. These findings are discussed as possible mechanisms for conserving body water.
INTRODUCTION
Black-tailed prairie dogs (Cyno~ys ~~~#vic~ffnus) are well-adapted to xeric environments. Reinking et al. (1977) found that black-tailed prairie dogs exhibit heat stress adaptations when exposed to high ambient temperatures: heat storage increased and oxygen consumption and evaporative water loss decreased. Pfeiffer et al. (1979) found that black-tailed prairie dogs maintained normal blood composition after prolonged starvation, with neither hypoglycemia nor ketosis resulting from deprivation of food and water. Respiratory exchange ratios are reduced in black-tailed prairie dogs when fasted (Pfeiffer et nl. 1979; Wallace et al., 1984) indicating that these animals metabolize primarily fats when subjected to this stress. Urea hydrolysis occurs in black-tailed prairie dogs and apparently increases in starved animals (Wallace et al., 1984). These physiological adaptations may reduce water loss. White-tailed prairie dogs (Cynomys leucurus) are known to be obligate hibe~ators (Tileston and Lechleitner, 1966; Hoogland, 1981; Bakko and Nahorniak, 1986; Harlow and Menkens, 1986). Although black-tailed prairie dogs are not considered true hibernators, they have been reported to enter torpor. Anthony (1955) observed what he referred to as “cold narcosis” in black-tailed prairie dogs. Hamilton and Pfeiffer (1977) found that black-tailed prairie dogs maintained at an ambient temperature of 6”C, had T,, ranging from 8 to 13°C. Harlow and Menkens (1986) observed bouts of torpor in laboratory black-tailed prairie dogs kept at 7°C. Fluctuations in r, of these animals have been reported diurnally (Bakko et al., 1988; Reinking et ai., 1977), as well as seasonally (Bakko et al., 1988). Thomas and Riedesel (1975) suggested that black-tailed prairie dogs are capable of hibernation, based on the results of ECG’s performed on perfused hearts at
10°C. Some authors have suggested that the lack of hibernation in black-tailed prairie dogs may contribute to the high degree of sociality in these communal animals (Tileston and Lechleitner, 1966; Michener, 1983). White-tailed prairie dogs have been observed entering periods of summer estivation while blacktailed prairie dogs remain active all summer (Tileston and Lechleitner 1966). It is the purpose of this study to determine the effects of dietary deprivations on T, and VO, in a laboratory colony of black-tailed prairie dogs. MATERIALS AND METHODS Twenty black-tailed prairie dogs, captured at the C. M. RusseIl Wildlife Refuge in eastern Montana, were used in this study. These animals were caged singly and fed three Wayne lab blocks, i carrot, and i head of lettuce each day. Free water was not provided. Normal photoperiod was maintained with natural lighting. Animals were assigned to one of the following categories. Control: animals mainline as stated above; FWD: animals given no food or water; WD: animals deprived of their water source (carrots and lettuce) and provided with three lab blocks daily. Data collection started after 1-2 weeks of fasting. Prairie dogs were weighed to the nearest gram regularly, using a Torbal torsion balance. Body temperature During the experiment, deep rectal temperatures were taken regularly on prairie dogs, using a Yellow Springs tele-the~ometer (YSI Model 44TD) calibrated with a mercury thermometer traceable to the National Bureau of Standards. These measurements were taken between 1400 and 1600 hr.
During the month of January, VO, was measured using a flow-through, steady state system, according to Hill (1972). Observed and expected VO, values were calculated
GAMY M. WALLACEand E. W.
854
and allometrically standardized for body weight according to Reinking et al. (1977). Statistical procedures
One-sided Mann-Whitney T statistics compared r, between the Control and experimental groups. Expected VO, values were compared to observed VO, values using the sign test based on the binomial distribution. One-sided Mann-Whitney T statistics were calculated for VO, data between Control and experimental groups. RESULTS Body temperature
Table 1 shows body weight, Tb (“C), observed and expected VOZ (ml O,/kg/hr), and days fasted for Control, FWD, and WD black-tailed prairie dogs. Control black-tailed prairie dogs had a mean T, of 36.2”C, while FWD and WD animals had mean T, of 33.4 and 30.4”C, respectively. FWD and WD blacktailed prairie dogs had significantly lower Tb than Control animals (P < 0.05 and P < 0.005, respectively). Oxygen consumption Control black-tailed prairie dogs had observed mean VO1 of 4.0 ml O,/kg/hr with expected mean VOz of 4.4 ml O,/kg/hr. FWD and WD animals had observed mean VOr of 4.4 and 2.9 ml O,/kg/hr, respectively while FWD and WD animals had expected mean VOXof 4.8 and 4.4 ml O,/kg/hr, respectively. There was no significant difference between observed VOr of Control and FWD prairie dogs, P > 0.05; while WD black-tailed prairie dogs had significantly lower observed VO, than Control prairie dogs, P = 0.05. Fifteen out of 20 observed VOr values were lower than expected for animals of their body weight. The sign test comparing observed and expected VO, values showed that observed VOr (all groups combined) was significantly lower than expected, P = 0.02.
Table
Animal no. Control
mean (SD) FWD
mean (SD) WD
mean (SD1
3 4 11 12 23 5 7 IS I8 22 1 10 14 17 19 21 13
DISCUSSION
Black-tailed prairie dogs range from northern Mexico to southern Canada, through the semi-arid great plains of the United States (Harlow and Menkens, 1986). Despite these conditions, blacktailed prairie dogs withstand this stress and apparently proliferate (Merriam 1901). Unlike the white-tailed prairie dog that hibernates during winter in the field (Bakko and Nahorniak, 1986) and hibernates in the laboratory (Harlow and Menkens, 1986), black-tailed prairie dogs do not hibernate (Tileston and Lechleitner, 1966; Hoogland, 1981) although Thomas and Riedesel (1975) concluded on the basis of ECG results of perfused hearts kept at 10°C that black-tailed prairie dogs have the ability to hibernate. FWD and WD black-tailed prairie dogs of this study did enter periodic bouts of torpor. Harlow and Menkens (1986) concluded that black-tailed prairie dogs are not induced into a state of torpor simply through an interaction with environmental cues, which induce torpor in other animals. These authors stated that a combination of winter photoperiod, decrease in temperature, and food deprivation, however, does induce torpor in some black-tailed prairie dogs. FWD and WD black-tailed prairie dogs of this study reduced metabolism as indicated in the depressed V02 and Tb values when compared to Controls (Table 1). When comparing allometrically standardized VOZ levels among all black-tailed prairie dogs combined (Control, FWD and WD), observed values were significantly lower than expected, during the month of January. Bakko et al. (1988) observed significantly lower T, during the month of January in field black-tailed prairie dogs. Although these authors did not observe torpor in these animals, they did record Tb as low as 31°C. They suggested that lowered Tb results in energy and water savings. Rubsamen (1980) observed that the rock hyrax, a resident of semi-arid conditions, decreased VO, with concomitant decreases in evaporative water loss and
1. Body weight, body temperature Body weight (g) 1065 1182 1306 1226 1183 1195(101) 1127 1292 1066 1187 1024 1139(105) IOCIO 1004 1124 1430 1163 845 1007 1081(184)
(G, 35.0 36.5 36.4 36.0 37.0 36.2 (0.8) 36.0 35.4 25.6 35.2 34.9 33.4 (4.4) 33.0 25.5 32.9 30.3 21.4 29.0 34.6 30.4 (3.3)
PFEIFFER
and oxygen consumption
w observed (ml %I kg/hr)
vo, expected (ml 0,l kg/hr)
3.8 5.4 3.7 3.6 3.7 4.0 (0.8) 4.2 3.5 8.1 2.5 3.5 4.4 (2.2) 3.9 2.5 2.3 2.9 2.0 1.9 5.0 2.9(1.1)
4.0 4.3 4.7 4.8 4.4 4.4 (0.3) 4.7 5.2 4.7 5.0 4.5 4.8 (0.3) 4.3 4.2 4.4 5.2 4.6 3.8 4.3 4.4 (0.4)
Days fasted 0 0 0 0 0 0 I2
12 17 12 I2 13 (2) 9 9
9 9 9 8 (2)
Prairie dog T, and VO, Tb in response to water restriction. The lowered Tb decreased the need for heat dissipation through the evaporation of water, thus reducing water loss. Bakko et al. (1988) stated that lowered r, has adaptive potential for body water conservation by reducing evaporative water loss. WD black-tailed prairie dogs in this study had the lowest Tb and VOZ values of any group. It may be hypothesized that because WD animals were provided with a dry food source that was consumed in small amounts, these animals then produced metabolic waste products, necessitating increased urination, thereby putting themselves into a greater water stress than FWD animals. This could explain why WD animals had depressed Tb and VO, values below those of Control and FWD animals. Harlow and Menkens (1986) showed that the number of torpid black-tailed prairie dogs increased with the removal of water fr6m their diets. Harlow and Menkens (1986) stated that enhanced urea recycling capacity could provide black-tailed prairie dogs with an additional means to cope with water deprivation and decreased the need to engage in torpor until conditions become extreme. Wallace et al. (1984) showed that black-tailed prairie dogs did exhibit urea hydrolysis, and when comparing the ratio of relative urea hydrolysis to urea excretion in the urine between FWD and Control black-tailed prairie dogs, FWD animals apparently increased urea hydrolysis over that of Controls (2.6 and 1.8, respectively). Urea recycling provides an advantage of reducing the amount of urinary water loss needed to dilute and flush urea from the body (Hochachka and Somero, 1984) in light of the fact that black-tailed prairie dogs do not concentrate urine to the same level as do other arid-living species (Hamilton and Pfeiffer, 1976; Reinking et al., 1977). Reinking et al. (1977) stated that metabolic and temperature responses seem to play a major role in black-tailed prairie dog water balance. This study has shown that laboratory FWD and WD black-tailed prairie dogs decrease body temperature and oxygen consumption when compared to Control animals. Water restriction (WD regime) apparently accentuates these responses over that of FWD animals. Torpor was observed in some animals. These physiological responses to dietary deprivation provide black-tailed prairie dogs with a possible means to conserve body water when food and water are limited.
855 REFERENCES
Anthony A. (1955) Behavior patterns in a laboratory colony of prairie dogs, Cynomys ludovicianus. J. Mammal. 36, 69-78.
Bakko E. B., Porter W. P. and Wunder B. A. (1988) Body temperature patterns in black-tailed prairie dogs in the field. Can. J. Zool. 66, 1783-1789. Bakko E. B. and Nahorniak J. (1986) Torpor patterns in captive white-tailed prairie dog, Cynomys leucurus. 1. Mammal. 67, 516-578.
Hamilton J. D. and Pfeiffer E. W. (1977) Effects of cold exposure and dehydration on renal function in blacktailed prairie dogs. J. appl. Physiol. Resp. Environ. Exercise Physiot. 42, 295-299.
Harlow H. J. and Menkens G. E. Jr (1986) A comparison of hibernation in the black-tailed prairie dog, white-tailed prairie dog, and Wyoming ground squirrel. Can. J. Zool. 64, 793-796.
Hill R. W. (1972) Determination of oxygen consumption by use of the paramagnetic oxygen analyzer. J. appl. Physiol. 33, 261-263.
Hochachka P. W. and Somero G. N. (1984) Biochemical Adaptations. pp. 239-241. Princeton University Press, Princeton, NJ. Hoogland T. L. (1981) The evolution of coloniality in whitetailed orairie dogs and black-tailed orairie dogs (Cvnomvs leucurus and C.-ludovicianus). Ecology 62, 252-272. ’ Merriam C. H. (1901) The Prairie Dog of the Great Plains. pp. 257-270. Yearbook, U.S. Department of Agriculture. Michener G. R. (1983) Kin identification, matriarchies, and the evolution of sociality in ground-dwelling s&rids. In Recent Advances in the Study of Mammalian Behavior
(Edited by Eisenberg J. F. and Kleiman D. G.), No. 7. pp. 528-572. Spec. Publ. Am. Sot. Mammal. Pfeiffer E. W., Reinking L. N. and Hamilton J. D. (1979) Some effects of food and water deprivation on metabolism in black-tailed prairie dogs Cynomys ludovicianus. Comp. Biochem. Physiol. 63, 19-22.
Rubsamen K. and Kettembeil S. (1980) Effect of water restriction on oxygen uptake, evaporative water loss and body temperature of the rock hyrax. J. camp. Physiot. 138, 3 15-320.
Reinking L. N., Kilgore D. L., Fairbanks E. S. and Hamilton J. D. (1977) Temperature regulation in normothermic black-tailed prairie dogs, Cynomys ludovicianus. Comp. Biochem. Physiol. 5lA, 161-165. Tileston J. V. and Lechleitner R. R. (1966) Some comparisons of the black-tailed and white-tailed prairie dogs in north-central Colorado. Am. Midt. Nat. 75, 292-316. Thomas T. H. and Riedesel M. L. (1975) Evidence of hibernation in the black-tailed prairie dog Cynomys ludovicianus. Cryobiology 12, 559.
Wallace G. M., Fevold H. R. and Pfeiffer E. W. (1984) Urea hydrolysis in black-tailed prairie dogs (Cynomys ludovicianus). Comp. Biochem. Physiol. 78A, 219-283.
