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Field Evaluation of Telazolr and Ketamine-Xylazine for Immobilizing Black Bears Author(s): Thomas H. White, Jr., Madan K. Oli, Bruce D. Leopold, Harry A. Jacobson, John W. Kasbohm Source: Wildlife Society Bulletin, Vol. 24, No. 3, Predators (Autumn, 1996), pp. 521-527 Published by: Allen Press Stable URL: http://www.jstor.org/stable/3783337 Accessed: 04/08/2009 09:47 Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/action/showpublisher?publishercode=acg. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission. JSTOR is a not-for-profit organization founded in 1995 to build trusted digital archives for scholarship. We work with the scholarly community to preserve their work and the materials they rely upon, and to build a common research platform that promotes the discovery and use of these resources. For more information about JSTOR, please contact support@jstor.org. Allen Press is collaborating with JSTOR to digitize, preserve and extend access to Wildlife Society Bulletin. http://www.jstor.org

EVALUATION OF BEAR IMMOBILANT 521 Field evaluation of Telazol? and ketamine- xylazine for immobilizing black bears Thomas H. White, Jr., Madan K. Oli, Bruce D. Leopold, Harry A. Jacobson, and John W. Kasbohm Abstract Telazol? and ketamine-xylazine have become the 2 most frequently used chemical immobilants for black bear (Ursus americanus). We compared effects of Telazol and ketaminexylazine (KX) in 60 black bear immobilizations in relation to 5 response parameters during summers of 1992-1994 in southeastern Arkansas. Induction times did not differ (P = 0.99) between immobilants, and no induction-dosage relationship was observed with either Telazol (P = 0.52) or KX (P = 0.70). Heart rates did not differ (P = 0.28) between immobilants, and both induced mild tachycardia. With use of Telazol, respiration rate increased (r = 0.53, P = 0.06) with increasing body temperature. No correlation (r = -0.54, P = 0.34) between respiration rate and body temperature was detected with use of KX. Compared to Telazol, use of KX resulted in higher (P = 0.06) incidence of hyperthermia (i.e., body temperature >400C), with more than twice as many KX-treated bears becoming hyperthermic as Telazol-treated bears. Increased pulmonary ventilation may have been a factor in minimizing heat stress in Telazol-immobilized bears. With use of KX, there were 4 episodes of sudden spontaneous recovery by immobilized bears. Recovery of Telazol-immobilized bears was gradual and predictable, although restraint time was 2.5 times longer than with KX due to lack of an effective antagonist to Telazol. Based on our observations, we recommend use of Telazol over ketamine-xylazine as a safe and effective immobilant for black bears. Key words black bear, chemical immobilization, hyperthermia, ketamine, rectal temperature, Telazol?, Ursus americanus, xylazine During the last decade, Telazol? (1:1 mixture of tiletamine hydrochloride [HCL] and zolazepam HCL; Elkins-Sinn, Inc., Cherry Hill, NJ 08003) and ketamine HCL-xylazine HCL (2:1 mixture) have become the 2 principal drugs used for chemical immobilization of black bears (Ursus americanus; Cook 1984, Hellgren and Vaughan 1989, Jonkel 1993, McLaughlin 1993). Detailed pharmacological descriptions of these compounds are reported in Cook (1984) and Massopust et al. (1973) for ketamine-xylazine (KX) and Telazol, respectively. Previous reports on the physiological responses of immobilized black bears to KX (Addison and Kolenosky 1979, Cook 1984, Hellgren and Vaughan Captured black bear before immobilization. Address for Thomas H. White, Jr., Madan K. Oli, Bruce D. Leopold, and Harry A. Jacobson: Department of Wildlife & Fisheries, Mississippi State University, Mississippi State, MS 39762, USA. Address for John W. Kasbohm during this research: Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA. Current address for John W. Kasbohm: Okefenokee National Wildlife Refuge, Rt. 2, Box 3330, Folkston, GA 31537, USA. Wildlife Society Bulletin 1996, 24(3):521-527 Peer refereed

522 Wildlife Society Bulletin 1996, 24(3):521-527 1989) and Telazol (Stewart et al. 1977, McLaughlin 1993) involved singular administration of either compound to black bears in populations in different regions or under dissimilar environmental conditions. Differences in reported response parameters may be attributed to geographic or temporal variations in environmental conditions that affect physiological responses of immobilized animals (Stewart et al. 1977, Hellgren and Vaughan 1989). For example, Hellgren and Vaughan (1989) reported rectal temperatures ranging from 35.5?C to 43.0?C for black bears snaretrapped and immobilized with KX in the Great Dismal Swamp of Virginia, while Addison and Kolenosky (1979) reported temperatures from 36.5?C to 41.0?C for black bears in central Ontario. Rectal temperatures of bears immobilized with Telazol in California have ranged from 36.9?C to 39.2?C (Stewart et al. 1977). Variations in induction times, as well as heart and respiration rates, also have been reported for both immobilants (Stewart et al. 1977, Addison and Kolenosky 1979, Cook 1984, Jonkel 1993, McLaughlin 1993). Because of the inherent danger to humans in handling black bears and the need to minimize capture-related injuries and mortalities, selection of an appropriate immobilant is essential (Jonkel 1993). Selection should be based on a comparison of empirical data on immobilants administered to a given popula- tion under similar environmental conditions. Researchers and managers currently select an immobilant without knowledge of the comparative performance of the 2 drugs under given conditions. Therefore, our objectives were to: (1) compare responses of black bears under similar field conditions in the same population to chemical immobilization by Telazol and KX, (2) evaluate reliability of measured parameters for detecting differences between Telazol and KX, and (3) provide recommendations for selecting Telazol or KX for immobilizing black bears. Methods Sixty black bears (29 males, 31 females) were captured with modified spring-activated cable snares (Johnson and Pelton 1980) during June through August 1992-1994 on the White River National Wildlife Refuge (WRNWR) and adjacent private lands in Desha, Phillips, and Arkansas counties, Arkansas. Trap sites were checked every morning (>0700 hrs) and afternoon (>1600 hrs). Captured bears were immobilized with either a 2:1 mixture of KX (n = 33) at a concentration of 200 mg/cc ketamine: 100 mg/cc xylazine, or Telazol (n = 27) at concentrations ranging from 100 to 250 mg/cc. Dosages of KX ranged from 4:2 to 16:8 mg/kg (x = 8:4, SE = 0.4:0.2); and dosages Female black bear being darted at White River National Wildlife Refuge. of Telazol from 2.6 to 10.3 mg/kg body weight (x = 5.4, SE = 0.4). Ketamine-xylazine was administered to all bears captured during 1992. Telazol was administered during 1993 and alternated with KX during 1994. Dosage varied because of a tendency to overestimate weights of bears with thick pelage, and because of occasional animals that required secondary injections. Drugs were administered intramuscularly in the shoulder or rump by a jabstick or CO2-powered dart pistol and disposable darts (Pneu- Dart, Inc., Williamsport, Pa.). We recorded time of drug administration to the nearest minute. Following drug administration, we observed bears from a distance of approximately 30 m until they were recumbent. We considered bears tractable when we observed no head-lifting response to auditory or tactile stimuli (Stewart et al. 1977, Addison and Kolenosky 1979, Jonkel 1993). Induction time was time from initial drug administration to tractability measured to the nearest minute. Once tractable, bears were immediately positioned into shade and kept out of direct sunlight. We then sexed, weighed, and measured bears and took a rectal temperature to the nearest 0.05?C (0.1?F) using a standard digital medical thermometer. We separated adults (>4 yrs) from subadults (<4 yrs) by extracting an upper first premolar for aging (Willey 1974). Reproductive status (estrus or lactation) was recorded for all females. Heart and respiration rates were recorded for most bears beginning in 1993. Behavioral and other responses (e.g., staggering, vomiting, salivation, vocalization) were noted. Following handling procedures, bears immobilized with KX were administered yohimbine HCL intra-

Researchers check temperature of large male black bear. venously at 0.8-6.0 (x = 2.0, SE = 0.2) cc/45 kg body weight as an antagonist to xylazine (Ramsay et al. 1985, Garshelis et al. 1987). Bears immobilized with Telazol were allowed to remain recumbent until ambulatory, as there is currently no antagonist to Telazol (Jonkel 1993). Restraint time was time from initial tractability to time of voluntary ambulation measured to the nearest minute. All trapping and handling procedures were conducted in accordance with Mississippi State University Animal Care and Use Protocol No. 93-042. Drug treatment (Telazol or KX) and sex were considered as independent variables, with induction time, rectal temperature, heart rate, respiration rate and restraint time as dependent variables. Respiration and heart rates were normalized by natural log transformation and compared between drug treatments with t- tests (Sokal and Rohlf 1981:226). Induction times were normalized by square-root transformation and compared by 2-way analysis of variance (ANOVA; Sokal and Rohlf 1981:321) with interaction with sex and drug as main effects. Telazol restraint times also were normalized by square-root transformation and compared between sexes with t-tests. Rectal temperatures and normalized induction and restraint times were compared between lactating and nonlactating females with t-tests. Because yohimbine HCL was administered to KX-immobilized bears at the end of handling procedures, restraint time for those bears was a function of handling time. Therefore, a statistical comparison with Telazol restraint time was not done. No transformations of body weight, ambient temperature, rectal temperature or dosage were performed because Shapiro-Wilk normality statistics were high (>0.95) in relation to sample sizes. Body weights were compared between sexes with t-tests. Ambient temperatures during immobilizations were recorded at the WRNWR weather station (Natl. Weather Serv. Stn. Index No. 03-6376-6) and compared between treatments by t-tests. Rectal tem- Evaluation of bear immobilant * White et al. 523 perature was analyzed by 2-way ANOVA, with interaction with sex and drug as main effects. Because of the potential influence of body weight on physiological responses to immobilization (Larsen 1971, Stewart et al. 1974, Cook 1984), analysis of covariance (ANCOVA; Sokal and Rohlf 1981:509) was used to compare induction times and rectal temperatures between drug treatments, using body weight as the covariate. Pearson product-moment correlations and linear regressions were used to detect any significant positive relationships between measured parameters. Because of the biological importance of physiological parameters during chemical immobilizations, we considered differences significant at a = 0.10 to reduce Type II error (3) and maximize statistical power (1 - /) relative to observed sample sizes (Tacha et al. 1982, Taylor and Gerrodette 1993, Conroy et al. 1995). When no difference was detected, power was calculated according to Cohen (1977) to assess probability of Type II error. Results and discussion Body weights Although body weights of KX-treated bears did not differ between sexes, there was a difference by sex for bears immobilized with Telazol (Tables 1 and 2). Among sexes, males differed in weight between drug treatments (Table 2). Seventy-three percent of male bears captured during 1992 were subadult. Conversely, 56% of males captured during 1993-1994 were adult. Because Telazol was not used in the study until 1993, a larger number of smaller males were immobilized with KX than with Telazol. However, body weights of Telazol-treated bears (n = 18) that were < the largest KX-treated bear (125 kg) did not differ from bears in the KX sample (Table 2). Induction time Mean overall induction time for KX (x = 17.7 min, SE = 2.4) and Telazol (x = 16.5 min, SE = 2.0) did not differ (F = 0.01; 1, 56 df; P = 0.99; 1 - P = 0.79) and was not affected by body weight (F = 2.09; 1, 57 df; P = 0.17; 1 - /3 = 0.69). No differences in induction times for adults and subadults were observed with Telazol or KX (Table 2). Induction times of lactating females (i.e., with cubs) versus nonlactating females did not differ with Telazol or KX (Table 2). Appar- ently, presence of cubs did not act as a significant factor affecting drug action in maternal females. There was no observed relationship between induction time and dosage for either Telazol (P = 0.52, r = 0.05, 1-3 = 0.11) or KX (P= 0.70, r= 0.10, 1-3 = 0.12). Secondary injections to effect initial tractability were required in 15 (44.1%) instances with KX and 7

524 Wildlife Society Bulletin 1996, 24(3):521-527 Table 1. Parameters measured on 60 black bears immobilized using Telazol? or ketamine-xylazine during June-August 1992-1994 in southeastern Arkansas. Telazol? (n = 27) ketamine-xylazine (n = 33) Male Female Male Female Parameter ix SE n i SE n i SE n x SE n Weight (kg) 154.0 12.0 11 64.6 2.4 16 66.4 7.1 18 59.1 3.7 15 Induction time (min) 18.6 3.4 11 15.1 2.4 16 17.5 3.2 18 17.9 3.7 15 Rectal temperature (C) 38.8 0.4 11 39.7 0.2 16 39.9 0.3 12 39.6 0.4 12 Restraint time (min) 164.6 21.1 6 131.8 25.2 14 61.9 6.0 18 60.3 6.9 15 Heart rate1 (per min) (101.0 9.0 10) (88.8 4.3 4) Respiration' rate (per min) (41.0 7.4 13) (32.0 7.3 5) t Pooled across sexes due to low sample size. (25.9%) with Telazol; we examined induction-dosage relationships using only those bears that required a single injection to effect tractability to avoid possible bias from multiple injections. Lack of response to initial injection could have resulted from subcutaneous injections, injections into nonvascularized adipose tissue, or different stress levels in captured animals (Stewart et al. 1974, Addison and Kolenosky 1979, Stirling et al. 1985, Loughlin and Spraker 1989). Rectal temperature Ambient temperatures during immobilizations ranged from 27.8?C to 37.2?C, averaging 32.4?C with little variation (SE = 0.4?C; Natl. Oceanic and Atmos. Adm. 1992, 1993, 1994) and did not differ between treatments (Table 2). Rectal temperatures of bears administered Telazol (n = 27) ranged from 37.1?C to 41.3?C (x = 39.3?, SE = 0.37?) and of bears administered KX (n = 24) from 37.2?C to 41.9?C (x = 39.7?, SE = 0.42?) and did not differ (F = 0.13; 1, 48 df; P = 0.73; 1-3 = 0.58) between treatments, but showed some influence of body weight (F = 3.41; 1, 48 df; P = 0.08), with Telazol-treated males averaging lower temperatures in conjunction with greater body weights (Table 1). Rectal temperatures of lactating and nonlactating females did not differ for KX or Telazol (Table 2). Temperatures above 40?C require corrective actions such as artificial cooling of the animal or premature reversal of the immobilant (Hellgren and Vaughan 1989), which may be impractical or undesirable under some field conditions. There are 2 probable and synergistic causes of the observed relationships. First, Telazol does not alter thermoregulatory ability as xylazine does (Stirling et al. 1985, Jonkel 1993). Thus, bears immobilized with Telazol may be less prone to hyperthermia than those immobilized with KX. Secondly, because of greater mass, larger bears may be less likely than smaller bears to experience sudden or drastic changes in body temperature. According to Hellgren and Vaughan (1989), black bears become hyperthermic when rectal temperatures reach 40?C. Temperatures above 40?C require corrective actions such as artificial cooling of the animal or premature reversal of the Table 2. Parameter comparisons based on t-tests for 60 black bears immobilized with Telazol? (TL) and ketamine-xylazine (KX) during June-August 1992-1994 in southeastern Arkansas. Test statistics Comparisons t df P 1 -_ Weight KX? c 0.91 25 0.37 0.24 TL? 2 7.38 10 <0.001 KX-TL, 6.17 16 <0.001 KX-TL (<125 kg) 0.12 48 0.90 0.10 Induction time KX adult-subadult 0.95 25 0.35 0.25 TL adult-subadult 0.23 4 0.83 0.11 KX lactating-nonlactating 0.67 8 0.52 0.17 TL lactating-nonlactating 1.17 13 0.26 0.32 Ambient temperature KX-TL 0.51 37 0.61 0.13 Rectal temperature KX lactating-nonlactating 0.20 7 0.85 0.11 TL lactating-nonlactating 0.57 13 0.58 0.15 Heart rate KX-TL 1.14 11 0.28 0.28 Respiration rate KX-TL 0.43 11 0.68 0.18 Restraint time (TL only) '$- 1.07 15 0.30 0.28 Adult-subadult 0.81 1 0.57 0.16 Lactating-nonlactating 0.64 11 0.53 0.40 a Statistical power of test. a

Evaluation of bear immobilant * White et al. 525 immobilant (Hellgren and Vaughan 1989), which may be impractical or undesirable under some field conditions. A G-test (Sokal and Rohlf 1981:735) of independence of immobilant and incidence of hyperthermia detected a higher (G = 3.48, 1 df, P = 0.06) incidence of hyperthermia with KX immobilization. Of 18 bears immobilized with Telazol, 4 (22.2%) experienced rectal temperatures >40?C. However, of 24 bears immobilized with KX, 12 (50%) had rectal temperatures >40?C. Because of the observed influence of body weight on rectal temperature, only Telazol-treated bears weighing < the largest KX bear (125 kg) were compared with the KX sample. More than twice as many bears immobilized by KX became hyperthermic and, thus, in need of corrective actions than those immobilized by Telazol. Heart and respiration rates Normal heart rate for black bears is 60-90 beats/ minute (bpm; Jonkel 1993), with adults tending toward the lower part of the range. Heart rates for Telazol-treated bears (n = 10) ranged from 72 to 172 bpm. For KX-treated bears, heart rates (n = 4) ranged from 80 to 100 bpm. Both immobilants induced mild tachycardia (Table 1), with no difference detected between drug treatments (Table 2), possibly due to low sample size. Respiration rates for Telazol-treated bears (n = 13) ranged from 10 to 92/minute and for KX-treated bears (n = 5) ranged from 17 to 60/minute (Table 1) and did not differ between treatments (Table 2). With Telazol, respiration increased with increasing body temperatures (r = 0.53, P = 0.06); with KX, respiration was not correlated with body temperature (r = -0.54, P = 0.34, 1 - /3 = 0.26). Other researchers have reported that KX causes respiratory depression in bears (Addison and Kolenosky 1979, Cook 1984, Jonkel 1993). However, Telazol does not alter respiratory function at anesthetic dosages (onkel 1993, McLaughlin 1993). Of the 6 cases of hyperthermia with Telazol, mean respiration rate (60/min) was higher (t = 3.24, 10 df, P = 0.009) than that of nonhyperthermic bears (25/min). Thus, the lower incidence of hyperthermia observed with Telazol may have been partially attributable to increased pulmonary ventilation in response to increasing body temperature (Stirling et al. 1985). Panting, indicative of acute heat stress in black bears at rectal temperatures >42.0?C (Hellgren and Vaughan 1989), was not observed. The highest rectal temperature recorded during this study was 41.9?C for a KX-immobilized female. Our use of frozen "blue ice" packs applied to the inguinal area of bears as a prophylactic measure may have prevented excessive heat stress. Restraint time Because restraint times were not statistically comparable between treatments, ranges and means are reported for comparative purposes only. With use of KX, restraint time ranged from 21 to 145 minutes (x = 61.2, SE = 4.6), while with Telazol, restraint time ranged from 45 to 420 minutes (x = 150.5, SE = 18.6), with only 1 observation >236 minutes. Because Telazol is metabolized and excreted primarily by the kidneys, preexistent renal pathology or impairment may result in increased restraint times (Stewart et al. 1977). For the Telazol treatment, no difference in restraint time between sexes was detected (Table 2). Restraint time for adults (137.6 min) and subadults (176.1 min) did not differ (Table 2). Restraint time for lactating (134.0 min) and nonlactating (112.0 min) females also did not differ (Table 2). There was no apparent relationship between body weight (R = 0.1, P = 0.63, 1 - / = 0.14) or dosage (R = 0.09, P = 0.95, 1 - / = 0.13 ) and Telazol restraint times. Behavioral responses Induction of both immobilants was characterized by gradual loss of coordination in a posterior to anterior sequence, followed by either lateral or sternal recumbency. Swaying of the head preceded tractability in virtually all cases. Vocalizations (e.g., groans, sighs) occurred only with administration of KX. Mild salivation occurred with both immobilants and normal swallowing reflexes were not inhibited. One KX-immobilized female experienced convulsions soon after immobilization on 2 July 1992. Her rectal temperature was 41.9?C and yohimbine HCL was immediately administered. Recovery was rapid (<3 min) and the bear trotted off in circles. Because this animal was not radiocollared, her fate is unknown. Vomiting occurred in 1 Telazol-immobilized female during the recovery phase. Recovery phase of Telazol-immobilized bears was gradual and predictable, characterized by increasing coordination in an anterior to posterior sequence, coupled with head swaying and persistent licking of the tongue. Twitching of the facial musculature and pedal-reflex response characterized the early recovery phase of KXimmobilized bears following yohimbine HCL injection. With use of KX, there were 4 instances of sudden and violent recovery not attributable to antagonist administration. During these episodes, bears attempted to run away, stumbling into trees and other obstacles. Statistical power and parameter reliability Low statistical power, encountered in several comparisons (Table 2), was primarily a function of large

526 Wildlife Society Bulletin 1996, 24(3):521-527 variability relative to the magnitude of differences between means (Table 1). This was particularly evident for within-treatment comparisons due to reduced sample sizes. However, for between-treatment comparisons (i.e., Telazol vs. KX), induction time and rectal temperature parameters yielded greater statistical power (>0.58) and reliability to detect actual differences than other measured responses, given observed sample sizes. Heart and respiration rates, although yielding lower power and reliability in this study, are nonetheless important response parameters which may have been more statistically reliable had sample sizes for these parameters been comparable to those of rectal temperature and induction time (Table 1). Recommendations Based on our observations, we believe that Telazol has specific advantages over KX for immobilizing black bears. During hot, humid conditions the incidence of hyperthermia can be significantly reduced by use of Telazol, as suggested by Hellgren and Vaughan (1989). Because Telazol does not affect thermoregulatory ability, hypothermia may be avoided with use of Telazol during cold conditions (Stirling et al. 1985, Loughlin and Spraker 1989). Telazol is available in free-base powdered form in 500-mg vials. It can be reconstituted in the field by adding 1-5 ml of sterile isotonic water, allowing for various concentrations of the immobilant. This flexibility allows for high dosages to be administered in small volumes and with single injections, a distinct advantage over the static concentration of liquid KX when immobilizing large bears. However, reconstituted Telazol should be used within 4 days, or within 2 weeks if refrigerated (Jonkel 1993). When used in extremely cold weather, Kreeger et al. (1990) recommended reconstitution using a water and propylene glycol mixture to prevent freezing of the aqueous preparation in darts and needles. Behavior of Telazol-immobilized bears is extremely predictable during recovery phase, although total restraint time is lengthy compared to KX. We agree with Jonkel's (1993) recommendation for the use of Telazol over KX in situations where longer restraint time is desired (e.g., translocating bears, lengthy handling procedures). Further, we recommend Telazol for immobilization of large bears for safety reasons considering the episodes of sudden and explosive arousal of animals we experienced with use of KX. A disadvantage of Telazol is the often unnecessarily long restraint time. Consequently, we recommend KX for situations in which restraint time needs to be minimized, such as when handling females with cubs. For all other situations, we recommend a Telazol dosage of 4.4-5.5 mg/kg body weight (200-250 mg/100 lbs) for safe and effective immobilizations. Although not yet commercially available, RO 15-1788 (an antagonist to zolazepam HCL) has been suggested as a potential antagonist to Telazol (Jonkel 1993); this may eliminate the disadvantage of lengthy restraint times with the use of Telazol. Dopram? (Doxapram HCL), a respiratory stimulant, has been used to counter the effect of Telazol in grizzly bears (Ursus arctos horribilis), but arousal was soon followed by relapse to a tractable state (Jonkel 1993). Acknowledgments. We thank the U.S. Department of Agriculture Forest Service-Southern Forest Experiment Station, Boone and Crockett Club, Arkansas Nature Conservancy, Mississippi Department of Wildlife, Fisheries and Parks (MDWFP), National Council of the Paper Industry for Air and Stream Improvement, Inc., and the U.S. Department of Interior Fish and Wildlife Service-National Fish and Wildlife Foundation for providing funding. Accommodations, equipment, and field assistance were provided by the WRNWR, Anderson-Tully Company, Montgomery Island Hunting Club, and the Norris Hunting Club. We thank B. Wade, S. Snowden, P. Hudson, and S. Kaplan for donating fish for trap bait. Special thanks are due N. Hunter and L. Smith for assistance with trapping activities at WRNWR and the many graduate students and others who have assisted in the field, especially D. A. Miller, T. H. Eason, C. C. Shropshire, V. Woshner, D. Miller, M. D. Weinstein, L. M. Connor, C. D. Lovell, D. C. Jackson, S. Couch, C. Fikes, W. McKinley, M. Staten, A. J. Dolan, Q. J. Kinler, and L. Wade. Discussions with C. R. McLaughlin, M. R. Vaughan, and R. M. Pace provided helpful insight. We thank T. K. Day, K. B. Swenson, F. J. Vilella, E. C. Hellgren, and 2 anonymous reviewers for constructive comments on improving the manuscript. Literature cited ADDISON, E. M., AND G. B. KOLENOSKY. 1979. Use of ketamine hydrochloride and xylazine hydrochloride to immobilize black bears (Ursus americanus). J. Wildl. Dis. 15:253-258. COHEN, J. 1977. Statistical power analyses for the behavioral sciences. Academic Press, New York, N.Y. 474pp. CONROY, M. J., M. D. SAMUEL, AND G C. WHITE. 1995. Joural news. J. Wildl. Manage. 59:196-198. COOK, B. 1984. Chemical immobilization of black bears in Great Smoky Mountains National Park. Proc. East. Conf. Black Bear Res. Manage. 7:79-81. GARSHELLS, D. L., K. V. NOYCE, AND P.. DK. IAS. 1987. Yohimbine as an antagonist to ketamine-xylazine immobilization in black bears. Int. Conf. Bear Res. Manage. 7:323-327.

Evaluation of bear immobitant * White et al. 527 HELLGREN, E. C., AND M. R. VAUGHAN. 1989. Rectal temperatures of immobilized, snare-trapped black bears in Great Dismal Swamp. J. Wildl. Dis. 25:440-443. JOHNSON, K. G., AND M. R. PELTON. 1980. Prebaiting and snaring techniques for black bears. Wildl. Soc. Bull. 8:46-54. JONKEL, J. J. 1993. A manual for handling bears for managers and researchers. T. J. Thier, ed. Office of Grizzly Bear Recovery, U.S. Fish and Wildl. Serv., Missoula, Mont. 175pp. KREEGER, T. J., U. S. SEAL, M. CALLAHAN, AND M. BECKEL. 1990. Physiological and behavioral responses of gray wolves (Canis lupus) to immobilization with tiletamine and zolazepam. J. Wildl. Dis. 26:90-94. LARSEN, T. 1971. Capturing, handling, and marking polar bears in Svalbard. J. Wildl. Manage. 32:27-36. LOUGHLIN, T. R., AND T. SPRAKER. 1989. Use of Telazol? to immobilize northern sea lions (Eumetopias jubatus) in Alaska. J. Wildl. Dis. 25:353-358. MASSOPUST, L. C., L. R. WOLIN, AND M. S. ALBIN. 1973. The effects of a new phencyclidine derivative and diazepinone derivative on the electroencephalographic and behavioral responses in the cat. Life Sci. 3:1-10. MCLAUGHLIN, C. R. 1993. Notes on the use of Telazol? on denned black bears. Int. Bear News 2(1): 1. NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION. 1992. Climatological data: Arkansas, annual summary. Natl. Climatic Data Cent., Asheville, N.C. NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION. 1993. Climatological data: Arkansas, annual summary. Natl. Climatic Cent., Asheville, N.C. NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION. 1994. Climatological data: Arkansas, annual summary. Natl. Climatic Cent., Asheville, N.C. RAMSAY, M. A., I. STIRLING, L. O. KNUTSEN, AND E. BROUGHTON. 1985. Use of yohimbine hydrochloride to reverse immobilization of polar bears by ketamine hydrochloride and xylazine hydrochloride. J. Wildl. Dis. 21:396-400. SOKAL, R. R. AND F. J. ROHLF. 1981. Biometry. W. H. Freeman and Co., New York, N.Y. 859pp. STEWART, G. R., J. M. SIPEREK, AND V. R. WHEELER. 1977. Use of the cataleptoid anesthetic CI-744 for chemical restraint of black bears. Int. Conf. Bear Res. Manage. 4:57-61. STIRLING, I., E. BROUGHTON, L. O. KNUTSEN, M. A. RAMSAY, AND D. S. ANDRIASHEK. 1985. Immobilization of polar bears with Telazol? on the western coast of Hudson Bay during summer 1984. Canadian Wildl. Serv. Prog. Notes No. 157, Canadian Wildl. Serv., Edmonton, Alberta. 7pp. TACHA, T. C., W. D. WARDE, AND K. P. BURNHAM. 1982. Use and interpretation of statistics in wildlife journals. Wildl. Soc. Bull. 10:355-362. TAYLOR, B. L., AND T. GERRODETTE. 1993. The use of statistical power in conservation biology: the vaquita and the northern spotted owl. Conserv. Biol. 7:489-500. WILLEY, C. H. 1974. Aging black bears from first premolar tooth sections. J. Wildl. Manage. 38:97-100. Thomas (Tom) H. White, Jr. (photo) is a Ph.D. candidate in the Department of Wildlife and Fisheries at Mississippi State University. He received his B.S. in Natural Resources Management from the University of Tennessee at Martin and his M.S in Wildlife Management from Louisiana State University. From 1986 through 1992, Tom was employed with the Law Enforcement Division of the Tennessee Wildlife Resources Agency, where he worked several years as an undercover Wildlife Officer and later as Assistant Chief of Law Enforcement. His research interests include landscape ecological aspects of carnivore ecology, river floodplain ecosystems, tropical ecology, and human dimensions of resource management. Madan K. Oli, formerly a Ph.D. candidate in the Department of Wildlife and Fisheries at Mississippi State University, received his B.S in Zoology from Tribhuvan University in Kathmandu, Nepal, and his M.S. in Ecology from the University of Edinburgh. His research interests include wildlife ethology and endangered species conservation. Bruce D. Leopold is an Associate Professor of Wildlife Ecology in the Department of Wildlife and Fisheries at Mississippi State University. He received his B.S. in Forest Science from Pennsylvania State University, his M.S. in Forestry from Mississippi State University, and his Ph.D. in Wildlife Ecology from the University of Arizona. His research interests include predator-prey ecology and interactions and habitat assessment and management. Harry A. Jacobson is a Professor of Wildlife Ecology in the Department of Wildlife and Fisheries at Mississippi State University. He received his B.S. in Wildlife and Fisheries Biology from Michigan State University and his M.S. in Wildlife Management and Ph.D. in Fisheries and Wildlife from Virginia Polytechnic Institute and State University. His research interests encompass ecology and management of ungulates and harvest management strategies for cervids on private lands. John W. Kasbohm is an Ecosystem Ecologist for the U.S. Fish and Wildlife Service at the Okefenokee National Wildlife Refuge in Folkston, Georgia. Formerly, he held a postdoctoral position at Virginia Polytechnic Institute and State University, where he coordinated a taxonomy and genetics investigation of black bear populations throughout the southeastern United States. He received his Ph.D. in Wildlife Sciences from Virginia Tech and his M.S. in Entomology from the University of Wisconsin at Madison. Associate Editor: Brennan