Journal of Wildlife Management 74(1):174–180; 2010; DOI: 10.2193/2008-502
Tools and Technology Article
Technique, Safety, and Efficacy of Intra-
Abdominal Transmitters in
SONIA M. HERNANDEZ,1,2 Zoological Medicine Service, Department of Small Animal Medicine and Surgery, College of Veterinary Medicine,
and the Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
DANIEL J. GAMMONS, Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA
NICOLE GOTTDENKER, Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
MICHAEL T. MENGAK, Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA
L. MIKE CONNER, Joseph W. Jones Ecological Research Center, Route 2, Box 2324, Newton, GA 39870, USA
STEPHEN J. DIVERS, Zoological Medicine Service, Department of Small Animal Medicine and Surgery, College of Veterinary Medicine,
University of Georgia, Athens, GA 30602, USA
ABSTRACT The future management of nine-banded armadillos (Dasypus novemcinctus) requires solid space-use and activity data,
which are currently lacking and which radiotelemetry can provide. External radiotransmitters have not been successful applied with this
species. To make recommendations for intra-abdominal radiotransmitter placement in nine-banded armadillos, we 1) evaluated 4 different
anesthetic protocols for safety, efficiency, and cost-effectiveness; 2) evaluated a surgical technique for the intra-abdominal placement of
radiotransmitters that addresses problems described in previous studies; and 3) evaluated the physiologic and behavioral effects of such a
technique. We captured and surgically implanted 37 nine-banded armadillos using either butorphanol and isoflurane, ketamine alone,
ketamine and xylazine, or a combination of butorphanol, ketamine, and medetomidine for anesthesia. We recovered and necropsied
armadillos after the completion of the study. The objective and subjective assessment of butorphanol, ketamine, and medetomidine
combination protocol, followed by reversal of the anesthesia with atipamezole, showed that it was the best overall anesthetic protocol for
field use, providing both a smooth induction and fast recovery. We evaluated the fate and effects of radiotransmitters on 13 recovered
animals at the end of the study and found no adverse effects. We recommend the implantation of radiotransmitters that are allowed to free-
float within the abdominal cavity and specifically emphasize the need for strict aseptic technique. Wildlife managers and wildlife
veterinarians aiming to implant nine-banded armadillos with radiotransmitters will benefit from using the recommended anesthetic protocol
and surgical technique in future studies.
KEY WORDS Anesthesia, Dasypus novemcinctus, Georgia, intra-abdominal radiotransmitter, nine-banded armadillos,
Until the mid-1850s, nine-banded armadillos (Dasypus which are currently lacking. Radiotelemetry could provide
novemcinctus; hereafter, armadillo) were restricted within the necessary data; however, external transmitters, a
the United States to southern Texas. Through natural common radiotelemetry device, are impractical because of
dispersal and translocations, nine-banded armadillos are the armadillo’s compact body, flexible carapace, and
now common throughout 12 of the southeastern states burrowing behaviors (Jacobs 1979, Herbst 1991b).
(Humphrey 1974, Taulman and Robbins 1996, Engeman et Our objectives were to develop and evaluate 1) an
al. 2003), where sometimes they are classified as an invasive anesthetic protocol that was safe, efficacious, and cost-
species or as pests (Hawthorne 1994, Taulman and Robbins effective for field conditions; 2) a surgical procedure for the
1996). Armadillos can cause landscape damage, which may intra-abdominal placement of radiotransmitters that ad-
lead to conflicts with landowners (Mengak 2003) and may dressed problems previously described (Bond et al. 2000);
be significant predators for ground-nesting birds and and 3) the physiologic effects and utility of intra-abdominal
endangered species (Drennen 1989, Engeman et al. 2003, radiotransmitters. Previous studies have described anesthetic
Staller et al. 2005). Despite these concerns, most of the protocols for xenarthrans (Fournier-Chambrillon et al.
ecological information regarding armadillo home range, 2000, West 2007); however, we specifically evaluated a
habitat use, and activity patterns has been derived from protocol that would allow for surgical procedures under field
indirect studies or radiotelemetry investigations with small conditions.
sample sizes (Thomas 1980, Herbst 1991b, Zimmerman
1992, Schnell 1994, Bond et al. 2000). STUDY AREA
The future management of armadillos (e.g., recommen- We conducted our study at the 11,735-ha research facility of
dations for decreasing population numbers, eradication, or the Joseph W. Jones Ecological Research Center at Ichau-
translocation) requires solid space-use and activity data, way (JWJERC) near Newton, Georgia, USA, in the
1 southeastern Gulf Coastal Plain. Armadillos have been
Present address: Daniel B. Warnell School of Forestry and Natural reported in this location for approximately 50 years (Fitch
Resources, and the Southeastern Cooperative Wildlife Disease Study, 1952). Historically, JWJERC was managed as a quail
University of Georgia, Athens, GA 30602, USA (Colinus virginianus) hunting preserve; however, 40% of
174 The Journal of Wildlife Management N 74(1)
JWJERC is currently managed to conserve the natural MI), penicillin G (300,000 units [U]/mL [75,000 U/kg]
longleaf pine ecosystem, whereas the remaining 60% is SC; Aspen Veterinary Resources, Liberty, MO), and 0.09%
managed as multiple-use zones integrating wildlife and saline (60 mL SC; Hospira, Lake Forest, IL).
timber management. We delineated a 3,610-ha section of We evaluated the anesthetic protocols by recording 5
JWJERC for this study. lengths of time: 1) time to induction (i.e., time from
anesthetic administration to a surgical level of anesthesia,
METHODS which we defined as lateral recumbency and a lack of
We captured 37 adult armadillos (9 ad and 3 juv M, 23 ad response to a toe-pinch); 2) total time of surgery from
and 2 juv F, weighing 2.3–5.2 kg) either by visually incision to application of the last skin suture; 3) time of
locating them at night with an infrared camera (IR250; reversal administration; 4) time to spontaneous movement
Raytheon, Las Vegas, NV) and netting them by hand or by (i.e., time from ending anesthesia to sternal recumbency);
unbaited, wire cage traps (Tomahawk Live Trap Company, and 5) time to complete recovery (i.e., time from first
Tomahawk, WI; Hawthorne 1994). Captures took place spontaneous movement to preanesthetic status).
between 22 May 2005 and 20 March 2006. We transported We determined the subjective quality of each protocol by
armadillos to a laboratory, allowed them to acclimatize to recording 3 scores: 1) we termed the induction smooth if the
indoor temperatures (20–25u C), provided them with animal became anesthetized without thrashing or paddling
water, and did not handle them again until the following (score 5 1) and rough if we observed the contrary (score 5
day, when we weighed, sexed, and aged them according to 0); 2) we termed the anesthetic level and quality appropriate
established criteria (McDonough 1994). Because we were if the animal displayed adequate muscle relaxation for
interested in determining survival rates and sources of surgery, did not move or wake up before finishing surgery,
mortality, we did not permanently mark animals because and if cardiopulmonary parameters monitored were stable
permanent markings are known to potentially bias hunter (score 5 1), and we termed the anesthetic level and quality
and predator behavior (Kaine 1992). inadequate if additional drugs were needed to maintain
surgical anesthesia or if cardiopulmonary parameters were
Anesthetic Protocol not within expected limits (score 5 0); and 3) we termed the
We captured, handled, and performed anesthetic and recovery smooth if the animal regained consciousness without
surgical procedures on armadillos in compliance with the thrashing or paddling, and the animal completely recovered
University of Georgia’s Animal Care and Use Committee in a reasonable amount of time (,3 hr; score 5 1) and rough
(project A2004-10138-0). For all cases, the handler reached if we observed the contrary or the complete recovery was
inside the carrier, restrained the animal by the base of the lengthy (.3 hr; score 5 0).
tail, and delivered injections into either the quadriceps or
the semimembranosus muscle group of the hind limb. Surgical Technique
We evaluated 4 field anesthetic protocols with 4 groups Once we achieved a surgical level of anesthesia, we placed the
of armadillos: butorphanol and isoflurane (BI), ketamine animals in dorsal recumbency on a heating mat and prepared
alone (K), ketamine and xylazine (KX), or a butorphanol, the ventral abdomen surgically from the xiphoid process of
ketamine, and medetomidine combination (BKM). In the the sternum to the pubis, by first shaving the fine abdominal
BI group, we administered an intramuscular (IM) hairs and then using a 70% isopropyl alcohol and 2%
injection of butorphanol (0.1 mg/kg; Torbugesic [10 mg/ chlorhexidine scrub solution (ChlorhexiDerm; DVM Phar-
mL]; Fort Dodge Animal Health, Madison, NJ), and maceuticals, Saint Joseph, MO) as described in standard
30 minutes later, we physically restrained the armadillos surgical texts (Slatter 2003). The transmitters were crystal
and used a face-mask to induce them with isoflurane gas controlled, 2 stage, and powered by a lithium battery, and
(Isoflo; Abbott Laboratories, Abbott Park, IL). In the K they were cylindrical (79 mm long, 20 mm wide, weighing
group, we administered ketamine alone (65–89 mg/kg IM; 32 g) and encapsulated in electrical resin (model M1240;
Ketaset [100 mg/mL]; Fort Dodge Animal Health). In Advanced Telemetry Systems, Isanti, MN). We sterilized the
the KX group, we administered a combination of ketamine transmitters by submersion in 2% glutaraldehyde solution
and xylazine (40 mg/kg and 1 mg/kg IM, respectively; (Cidex; Advanced Sterilization Products, Irvine, CA) for
xylazine: Rompun [100 mg/mL]; Bayer Health Care, 30 minutes and aseptically rinsed them with 0.9% sterile
Shawnee Mission, KS). In the BKM group, we adminis- saline solution. To implant the transmitter, we first made a 4-
tered a combination of butorphanol, ketamine, and cm incision through the skin and subcutaneous tissue
medetomidine (0.1 mg/kg, 15 mg/kg, and 0.07 mg/kg overlying and immediately caudal to the umbilical scar,
IM, respectively; medetomidine: Domitor [1 mg/mL]; which exposed the thick, fibrous umbilical tissue. We sharply
Pfizer Animal Health, Exton, PA), and upon conclusion dissected the umbilical tissue with scissors, exposing the
of surgery, we administered atipamezole (administered at fragile union of the rectus abdominis muscles, which we also
the same volume as medetomidine, IM; Antisedan [5 mg/ bluntly dissected. Immediately medial to these muscles, we
mL]; Pfizer) to reverse the effects of medetomidine. identified the thin peritoneal membrane, lifted it with
Once anesthetized, all animals received meloxicam forceps, and incised it with scissors, gaining access to the
(0.1 mg/kg subcutaneously [SC]; Metacam [5 mg/mL] abdominal cavity. We inserted the transmitter into the
injection; Boehringer Ingelheim Vetmedica, St. Joseph, abdominal cavity and allowed it to free-float (Hernandez-
Hernandez et al. N Armadillo Transmitter Safety 175
Figure 1. We surgically implanted intra-abdominal radiotransmitters into 37 nine-banded armadillos (Dasypus novemcinctus) at the Joseph W. Jones
Ecological Research Center at Ichauway, near Newton, Georgia, USA, in the southeastern Gulf Coastal Plain, 2005-2006. We placed the armadillo in dorsal
recumbency and aseptically prepared the area immediately caudal to the umbilicus. (inset) The surgical skin incision was made immediately caudal to the
umbilical scar. The junction of the rectus abdominis muscles, which is merged with the umbilical scar, was surgically incised, followed by an incision through
the peritoneal membrane to a length that allowed placement of the transmitter in the abdominal cavity.
Divers et al. 2001; Fig. 1). We closed the surgical incision in translocated animals), and we released the remaining animals
2 layers, suturing the rectus abdominis muscles with at their capture site (i.e., resident animals). We located the
absorbable suture (2-0 gauge polydioxanone; Ethicon, Piscat- animals by triangulation 3–4 times per week. To determine
away, NJ) in a simple, interrupted pattern and then the the utility of the transmitter, we recorded the range of the
subcutaneous tissue with a simple, continuous pattern. We signal and our ability to locate animals. To determine
brought the skin into apposition by the subcutaneous closure transmitter effects, we compared the home range and survival
and closed it with surgical glue (Vetbond Tissue Adhesive; of the implanted animals to published values from other
3M, St. Paul, MN). We monitored heart rate, respiratory armadillo populations. To determine whether the transmitter
rate, and body temperature throughout the surgical proce- interfered with internal organ structure and function, we
dure. We noted hypoxemia (i.e., relative oxyhemoglobin described the fate and location of the transmitter on all
saturation ,90% by pulse oximeter) in the first 5 animals; animals found dead. In addition, we recaptured 9 animals
thereafter, we used supplemental oxygen by face mask (4 M, 5 F), euthanized them, and performed a full, gross
(0.5 mL/min) for the rest of the animals. On completion, examination in which we noted the location of the transmitter
we maintained the animals indoors in carriers until as well as whether it was free-floating or adhered to abdominal
completely recovered (i.e., back to preanesthesia status) while viscera. Euthanasia was achieved by IM administration of
monitoring their respiratory rate. 2 mL of a 50:50 combination of ketamine and xylazine and,
once deeply anesthetized, intracardiac administration of 2 mL
Transmitter Safety and Utility of pentobarbital euthanasia solution (Beuthanasia; Schering
We released armadillos within 24 hours after surgery. We Plough Animal Health, Kenilworth, NJ). We harvested
released 6 animals in areas away from their capture site (i.e., several sections of all major organs, fixed the samples in
176 The Journal of Wildlife Management N 74(1)
Table 1. We implanted radiotransmitters into 37 nine-banded armadillos (Dasypus novemcinctus) to evaluate 4 anesthetic protocols at the Joseph W. Jones
Ecological Research Center at Ichauway near Newton, Georgia, USA, from 22 May 2005 to 20 March 2006.a We divided armadillos into 4 anesthetic
groups. The mean anesthetic parameters measured to objectively and subjectively assess the utility of the 4 anesthetic protocols are summarized.
BI (n = 2, M) BMK (n = 19; 7 M, 12 F) KX (n = 14; 6 M, 8 F) K (n = 4; 1 M, 3 F)
stage Parameter BI SD BMK SD KX SD K SD
Induction Mean body wt (kg) 4.39 0.41 4.15 0.38 4.38 0.58 3.35 1.49
Drug doses (mg/kg) B: 0.09 0.01 B: 0.15 0.05 X: 4.2 1.3 K: 73 11
Isoflurane (%) I: 1.5–2.5 M: 0.07 0.01 K: 40 7
K: 17 7
Induction time (min) 17.5 3.5 12.2 6.9 10.3 4.3 16b
Proportion (%) of armadillos 0 94 1 0
receiving score of 1 for subjective
quality of induction
Surgery Respiratory rate (per min) 37 5.2 40 10.2 NR NR
Heart rate (per min) 88 2.3 79 5.0 NR NR
Mean temp (uC) 34.5 0.1 34.1 2.0 34.7 1.8 33.2 2.4
Mean surgery time (min) 41.0 30.1 18.3 25.7
Proportion (%) of armadillos 100 88 84 0
receiving score of 1 for subjective
quality of anesthesia
Recovery Atipamezole reversal (mg/kg) NA 0.31 0.03 NA NA
Mean complete recovery time (min) 32 2.1 13.7 5.4 .3 hr .3 hr
Proportion (%) of armadillos 100 100 0 0
receiving score of 1 for subjective
quality of recovery
Abbreviations: B, butorphanol; I, isoflurane; K, ketamine; M, medetomidine; NA, not applicable; NR, not recorded; X, xylazine.
Only recorded in a single animal.
10% neutral-buffered formalin, and submitted them for the other 2 groups, whereas it was .3 hours in the K and
histopathologic examination. KX group, yielding low qualitative scores. No animals died
upon capture or before, during, or within 24 hours of
RESULTS surgery, and all animals were completely recovered at the
Anesthetic Protocol time of release. We did not note any adverse effects
The BKM and KX groups yielded the best subjective quality sometimes associated with the drugs (e.g., excessive
of induction scores (1 or nearest 1); the shortest induction salivation, vomiting, regurgitation, or bloating). For each
was in the K group. The 2 animals in the BI group struggled animal, total surgical time averaged 20 minutes (range, 18–
significantly, and armadillos in the K group displayed 40 min), with the longest times reflecting the first 5
dissociative movements, causing their inductions to be procedures and the learning curve of the surgeon.
classified as rough and yielding low scores (Table 1).
All of the K group armadillos either required further doses Transmitter Safety and Utility
for adequate muscle relaxation or experienced negative The 6 translocated armadillos exhibited erratic movements
cardiopulmonary effects, yielding low subjective scores. The immediately after release, and their fates are unknown
level of anesthesia was adequate for surgery in all but 2 (Gammons et al. 2009). Excluding those animals, we obtained
animals in the BKM group: one required additional enough data to confidently evaluate transmitter safety and
ketamine IM to achieve surgical anesthesia, and one animal utility from 31 resident armadillos, of which, 6 died, 13
began recovering before the end of the surgical procedure, disappeared, and 12 survived until the end of the study. No
although no further drugs were needed. One animal moved resident armadillos died as a result of the surgical procedure.
slightly before the completion of the surgical procedure in Only one animal, which had sustained severe wounds from a
the KX group, without needing additional drugs. The best predator within days before her recapture, failed to survive .30
subjective scores for quality of anesthesia were in the BI, days after implantation. We monitored animals that died an
BKM, and KX groups. average of 107 days (range, 15–206), animals that disappeared
Return to spontaneous movement was smooth in the BI an average of 260 days (range, 118–377), and animals that
and BKM. We did not record return to spontaneous survived until the end of the study an average of 270 days
movement for the K or KX group because armadillos in (range, 89–360). The mean minimum convex polygon home
those groups generally remained in a sleep-like state range size of 27 armadillos with .30 locations was 8.7 ha.
(presumptively because of defense behavior) unless we Including both translocated and resident armadillos, we
applied vigorous external stimulus (e.g., shaking carrier), lost radiocontact with 17 animals (7 M, 10 F), and their
which made it difficult for us to determine when the time to transmitter fate was unavailable. We found 8 animals (3 M,
spontaneous movement occurred. The time to complete 5 F) dead; we recaptured and euthanized 9 animals (4 M, 5
recovery for the BI and BKM group was much shorter than F) at the completion of the study, and 3 animals continued
Hernandez et al. N Armadillo Transmitter Safety 177
transmitting an active signal, but we could not recapture Consequently, we abandoned this method early in the study
them. Of the 8 animals found dead, the causes of death were and do not recommend it.
unknown (n 5 1), gunshot (n 5 2), predation (n 5 3), We used ketamine alone in some animals because it is
vehicular collision (n 5 1), and crushed by a tractor (n 5 1). cost effective and commonly used by field researchers.
We examined the abdominal cavity of all animals when Ketamine alone may suffice for short procedures and those
possible (9 euthanized and 3 found dead) and found no that do not require muscle relaxation (Plumb 2008).
transmitter adhesions to abdominal organs or significant However, high doses (.60 mg/kg) were required to
inflammation. Histopathologic examination of the tissues achieve surgical planes of anesthesia, which can cause
from the armadillos found dead was not possible because of significant respiratory depression and lengthy, rough
extensive tissue autolysis. recoveries because of ketamine’s dissociative effect on the
central nervous system (Plumb 2008). In the K group,
DISCUSSION recoveries were considered very lengthy and the procedure
Anesthetic Protocol impractical for future use.
Because armadillos are solitary, primarily nocturnal, occupy The a2-adrenoreceptor agonist anesthetics, such as
thickly vegetated habitats, and are difficult to permanently xylazine and medetomidine, have gained popularity in
mark (Loughry and McDonough 2001), research on their wildlife immobilization, including for armadillos, because
space use using radiotelemetry could provide more reliable they synergize the effects of dissociative agents, such as
estimates than currently available. To our knowledge, this ketamine, and produce excellent muscle relaxation (Four-
study provides the largest sample size and longest duration nier-Chambrillon et al. 2000, Grimm 2007). Adding an a2-
of any radiotelemetry study on armadillos to date and the adrenoreceptor agonist to the drug protocol considerably
first attempt to objectively assess the effects and utility of lowers the dose of ketamine needed, compared with using
abdominal radiotransmitters in armadillos. Anesthetic ketamine alone, and simultaneously decreases the negative
combinations used in xenarthrans have recently been side effects associated with ketamine. We evaluated the use
reviewed (West 2007), but only one publication, to our of ketamine and xylazine because the combination is likely
knowledge, details modern anesthetic techniques for free- to serve the realistic budget and drug availability limitations
ranging armadillos (Fournier-Chambrillon et al. 2000). In often confronting field biologists (Fournier-Chambrillon et
general, the ideal anesthetic for field use is 1) easily applied; al. 1997). For example, based on our doses, the cost of
2) does not require specialized equipment; 3) provides rapid, butorphanol, ketamine, and medetomidine, reversed with
smooth inductions; 4) has a wide margin of safety; 5) can be atipamezole, is significantly higher than a combination of
reversed; and 6) results in smooth, rapid recoveries. We were ketamine and xylazine (US$4.14 vs. $1.24/5 kg of armadillo,
particularly interested in the overall quality of anesthesia and respectively).
the time to complete recovery. Rough recoveries require An added advantage to using combinations of a2-
confinement and can lead to unnecessary trauma for an adrenoreceptor agonists is the recent development of specific
animal. Lengthy recoveries (.3 hr) are not practical in field antagonists or reversal agents. We used atipamezole to
situations when an animal needs to be released quickly, can reverse the medetomidine portion of the BKM combination.
lead to hypothermia, and are associated with other adverse Atipamezole reverses medetomidine through competitive
anesthetic complications, such as organ damage from inhibition at the receptor site, whereas the comparatively
hypoxemia and low blood pressure, among others. The lower dose of ketamine used with this combination is
time to complete recovery for the BKM group was much metabolized quickly, which results in an animal that
shorter than any other group. This was expected because recovers faster. Adding the mixed agonist–antagonist opioid
atipamezole is a highly specific antagonist for medetomi- butorphanol to the ketamine and medetomidine combina-
dine, and thus, any remaining sedation after reversal can be tion provided both added relaxation and acted as a short-
attributed to ketamine and butorphanol. term analgesic. Butorphanol is commonly combined with
Face-mask induction with a gas inhalant, with or without other anesthetics in animals to ensure short-term pain
a premedicant such as butorphanol, is widely used to control upon recovery and to lower the dose of the other
anesthetize animals (Heath 2007) and has a wide margin of agents (Grimm et al. 1998, Carroll et al. 2005). We aimed
safety. However, face-mask induction requires specialized to release the armadillos within 24 hours after surgery and
equipment and physical restraint of an animal. We expected specifically did not want the surgical procedure to interfere
that administering butorphanol 30 minutes before face- with the animal’s behavior; thus, we aimed to minimize
mask induction would produce enough sedation to safely pain, using butorphanol for short-term relief and meloxicam
administer inhalant anesthesia (Grimm 2007). This was not for longer analgesia.
the case, and the armadillos struggled excessively. This type
of stress has been shown to adversely affect physiologic Transmitter Safety and Utility
parameters (i.e., heart rate, blood pressure, and oxygen We lost radiocontact with most of animals implanted with
demand), which can directly affect survival (Arnemo 2007). radiotransmitters. This could be due to a variety of factors,
In addition, armadillos can cause serious injury with their including dispersal, transmitter failure, or transmitters
claws, including deep skin lacerations, putting the handler at destroyed by gunshots, vehicle collisions, or predators.
risk for disease with Mycobacterium leprae (Williams 2001). Destruction of the transmitters is unlikely because 1) the
178 The Journal of Wildlife Management N 74(1)
leading biologist was generally notified when and where starvation and adhesions to internal organs in at least 2 more
armadillos on the property were killed by hunters, 2) cases.
vehicle-struck armadillos would have likely been found
while conducting telemetry, and 3) transmitters were not MANAGEMENT IMPLICATIONS
affected in 2 animals that were scavenged during the study. We recommend the butorphanol, ketamine, and medeto-
It is unlikely that most missing animals were the result of midine anesthetic combination, reversed with atipamezole.
transmitter failure; thus, we speculate that most of the Additionally, we recommend the implantation of radio-
missing animals dispersed, and we have no reason to believe transmitters that are allowed to free-float within the
that physiologic effects caused by the transmitter are related abdominal cavity and specifically emphasize the need for
to loss of radiocontact. Recapture rates in previous studies strict aseptic technique, which is likely to minimize infection
have been low (Jacobs 1979, Loughry and McDonough and adhesion rates. We conclude that the aforementioned
2001), leading those authors to suspect dispersal of a large anesthetic, surgical, and implantation techniques are safe
percentage of animals. Other studies on the movement of and should be considered for future radiotelemetry studies.
armadillos also suggest highly mobile patterns (Thomas
1980, Herbst 1991b, Zimmerman 1992, Schnell 1994, Bond ACKNOWLEDGMENTS
et al. 2000). We were able to collect data on the fate and We thank the wildlife laboratory at JWJERC, the numerous
effects of 13 of the 37 implanted radiotransmitters. There volunteers for assistance with data collection, particularly J.
was no macroscopic evidence of transmitter-related injury. Keenan, D. Temple, M. Blasier, and E. Mackey, and D.
All histopathologic lesions observed were consistent with Mulcahy for review of this manuscript. Funding was
parasites, pathogens, and conditions routinely described in provided in part by Jack H. Berryman Institute, the Jones
armadillos (Cheadle et al. 2001, Leighton 2001, DeLucia et Ecological Research Center, and a University research
al. 2002). assistantship to D. Gammons. Permanent surgical equip-
Although we did not have a control group to compare ment was loaned by the College of Veterinary Medicine,
with (e.g., from a direct observation study), it seems unlikely University of Georgia.
that the transmitters had negative effects on the behavior of
armadillos. Implanted armadillos generally began foraging
immediately upon release, and their mean home range size Arnemo, J. M., and N. Caulkett. 2007. Stress. Pages 103–111 in G. West,
G. Heard, and N. Caulkett, editors. Zoo animal and wildlife
was similar to what has been reported elsewhere (see table 4
immobilization and anesthesia. Blackwell, Ames, Iowa, USA.
in McDonough 2000) where other monitoring techniques Bond, B. T., M. I. Nelson, and R. J. Warren. 2000. Home range dynamics
have been used. We cannot rule out the possibility that and den use of nine-banded armadillos on Cumberland Island, Georgia.
habitat use was influenced by the surgical procedure, but a Proceedings of the Annual Conference of the Southeastern Association
of Fish and Wildlife Agencies 54:415–423.
comparison with other populations to evaluate this effect is
Bond, B. T., R. J. Warren, and M. I. Nelson. 2002. Winter mortality of
impractical. Habitat use in other armadillo populations has adult nine-banded armadillos (Dasypus novemcinctus) on Cumberland
been studied primarily using direct observation, and this Island, Georgia. Georgia Journal of Science 60:209–215.
technique can produce biased results because of differential Carroll, G. L., L. B. Howe, and K. D. Peterson. 2005. Analgesic efficacy of
preoperative administration of meloxicam or butorphanol in onychecto-
detection probabilities between habitats, whereas detection mized cats. Journal of the American Veterinary Medical Association
probability did not vary in our radiotelemetry study 226:913–919.
(McDonough 2000). More important, however, is the Cheadle, M. A., S. M. Tanhauser, J. B. Dame, D. C. Sellon, M. Hines, P.
indication that the surgical procedure did not appear to E. Ginn, R. J. MacKay, and E. C. Greiner. 2001. The nine-banded
armadillo (Dasypus novemcinctus) is an intermediate host for Sarcocystis
influence armadillo survival rates. Six of the 31 resident neurona. International Journal for Parasitology 31:330–335.
armadillos died of a variety of causes, but that is within the DeLucia, P. M., M. A. Cheadle, and E. C. Greiner. 2002. Prevalence of
rate of loss reported for this species (Bond et al. 2002). A Sarcocystis sarcocysts in nine-banded armadillos (Dasypus novemcinctus)
potential concern when speculating about survival is the from Florida. Veterinary Parasitology 103:203–205.
Drennen, D., D. Cooley, and J. E. Devore. 1989. Armadillo predation on
high number of animals that disappeared and whose fates loggerhead turtle eggs at two national wildlife refuges in Florida, USA.
are undetermined. However, given the length of time we Marine Turtle Newsletter 45:7–8.
monitored them before the loss of transmitter signals, we are Engeman, R. M., R. E. Martin, B. Constantin, R. Noel, and J. Woolard.
confident that the surgical procedure did not cause these 2003. Monitoring predators to optimize their management for marine
turtle nest protection. Conservation Biology 113:171–178.
animals to vacate their home ranges. Fitch, H. S., P. Goodrum, and C. Newman. 1952. The armadillo in the
Radiotransmitter implantation can have pathologic effects southwestern United States. Journal of Mammalogy 33:21–37.
on surrounding tissues (Guynn 1987, Mulcahy and Esler Fournier-Chambrillon, C., P. Fournier, and J. C. Vie. 1997. Immobiliza-
1999). Herbst (1991a) evaluated the effects of abdominal tion of wild collared anteaters with ketamine- and xylazine-hydrochlo-
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