Darting terrestrial primates in the wild: A primer

While a goal of many field primatologists is to observe subjects in as undisturbed a setting as possible, it is often necessary to anesthetize animals for any of a variety of reasons. In this paper, we review techniques for anesthetizing wild primates, based on our experience with more than a thousand such procedures carried out on baboons in East Africa. We consider the following: 1) rationales for anesthetizing a wild primate; 2) systems for the delivery of anesthetic and choice of anesthetic; 3) the darting process itself and issues relevant to the period between darting and the safe removal of the animal; 4) handling of an anesthetized primate; 5) medical complications associated with darting; 6) when to reanesthetize an animal; 7) the process of recovery from anesthesia and release of an awake animal; 8) safety issues for humans. The range of information that can be obtained through field anesthetizations, when carried out successfully, as well as the potential benefit for the animals involved, can be enormous. However, this process is not trivial from the standpoint of the dangers involved to both the subjects and to humans and because of the potential disruption of social behavior to the group. As such, anesthetizations in the field should not be carried out without a strong rationale and without a tremendous priority given to the safety and care of all involved. Am. J. Primatol. 44:155–167, 1998. © 1998 Wiley-Liss, Inc.     

Effects of inhalational anesthesia on blood gases and pH in California sea lions

Despite the widespread use of inhalational anesthesia with spontaneous ventilation in many studies of otariid pinnipeds, the effects and risks of anesthetic‐induced respiratory depression on blood gas and pH regulation are unknown in these animals. During such anesthesia in California sea lions (Zalophus californianus), blood gas and pH analyses of opportunistic blood samples revealed routine hypercarbia (highest P_CO2 = 128 mm Hg [17.1 kPa]), but adequate arterial oxygenation (P_O2 > 100 mm Hg [13.3 kPa] on 100% inspiratory oxygen). Respiratory acidosis (lowest pH = 7.05) was limited by the increased buffering capacity of sea lion blood. A markedly widened alveolar‐to‐arterial P_O2 difference was indicative of atelectasis and ventilation‐perfusion mismatch in the lung secondary to hypoventilation during anesthesia. Despite the generally safe track record of this anesthetic regimen in the past, these findings demonstrate the value of high inspiratory O₂ concentrations and the necessity of constant vigilance and caution. In order to avoid hypoxemia, we emphasize the importance of late extubation or at least maintenance of mask ventilation on O₂ until anesthetic‐induced respiratory depression is resolved. In this regard, whether for planned or emergency application, we also describe a simple, easily employed intubation technique with the Casper “zalophoscope” for sea lions.     

Relationship between gastrointestinal transit time and anesthetic fasting protocols in the captive chimpanzee, Pan troglodytes

Background Lengthy social separation and prolonged fasting time contribute to increased risks associated with anesthesia in captive primates. This study is an initial attempt to identify a safe pre‐anesthetic fasting procedure by identifying gastric emptying time (GET) and gastrointestinal transit time (GTT) of captive chimpanzees, Pan troglodytes. Methods Seven adult chimpanzees at the North Carolina Zoo immobilized for annual physical examinations were fed barium‐impregnated polyethylene spheres to measure GET. Eleven animals were individually fed a color dye marker and fecal passage was observed to determine GTT. Results Gastric emptying time (GET) was approximated to be >3 hours but <16 hours. The mean GTT was 16.5 hours. Conclusions This study indicates that a fasting time of 3 hours would allow for complete gastric emptying and could potentially replace the current overnight fast (≥16 hour) to help minimize complications associated with pre‐anesthetic fasting in captive primates.     

Capture of Alouatta guariba clamitans for the surveillance of sylvatic yellow fever and zoonotic malaria: Which is the best strategy in the tropical Atlantic Forest?

Howler monkey capture is an arduous and expensive task requiring trained and specialized professionals. We compared strategies and methods to most efficiently capture Alouatta guariba clamitans in remnants of the Atlantic Forest in Rio de Janeiro and its bordering states of Minas Gerais and São Paulo. We tested whether or not the success of expeditions in the forest with anesthetic darts, nets, and baited traps differed with and without the support of an information network, a contact chain built with key institutions and inhabitants to continuously monitor howler monkey presence. The influence of forest conditions (vegetation type and fragment size) upon darting success was also evaluated. We captured 24 free‐living A. guariba clamitans. No howler monkey was caught with traps, probably due to the predominantly folivore feeding to high local plant diversity providing a great variety of food options. Captures based on an information network were significantly more efficient in terms of numbers of caught monkeys than without it. Captures with darts were considerably more efficient when performed in semideciduous forests and small forest fragments as opposed to ombrophilous forests or large woods. Although we walked great distances within the forest searching for howler monkeys, all but one animal were captured at the forest fringes. Hindrances to search and the darting method in the Atlantic Forest, for example, the steep terrain, high tree canopies, hunt pressure, and low A. guariba clamitans population density, were mitigated with the use of the information network in this monkey capture. Moreover, the information network enhanced the surveillance of zoonotic diseases, which howler monkeys and other nonhuman primates are reservoirs in Brazil, such as malaria and yellow fever.     

Darting and marking techniques for an arboreal forest monkey,Cercopithecus ascanius

Techniques are described for capturing and marking redtail monkeys (Cercopithecus ascanius). An air-powered darting rifle and syringe darts loaded with a Ketamine-Rompun mixture were used for capture. Ketamine was used for maintaining anesthesia. Monkeys were darted 48 times and captured 27 times. In 24 of the 27 captures, the monkeys were released unharmed. Adult males were marked with radiotransmitters attached to collars of nylon webbing. Females received nylon webbing collars with colorcoded plastic washers for identification.     

The acute physiological response of polar bears to helicopter capture

Many wildlife species are live captured, sampled, and released; for polar bears (Ursus maritimus) capture often requires chemical immobilization via helicopter darting. Polar bears reduce their activity for approximately 4 days after capture, likely reflecting stress recovery. To better understand this stress, we quantified polar bear activity (via collar-mounted accelerometers) and body temperature (via loggers in the body core [T_abd] and periphery [T_per]) during 2–6 months of natural behavior, and during helicopter recapture and immobilization. Recapture induced bouts of peak activity higher than those that occurred during natural behavior for 2 of 5 bears, greater peak T_per for 3 of 6 bears, and greater peak T_abd for 1 of 6 bears. High body temperature (>39.0°C) occurred in T_per for 3 of 6 individuals during recapture and 6 of 6 individuals during natural behavior, and in T_abd for 2 of 6 individuals during recapture and 3 of 6 individuals during natural behavior. Measurements of T_abd and T_per correlated with rectal temperatures measured after immobilization, supporting the use of rectal temperatures for monitoring bear response to capture. Using a larger dataset (n = 66 captures), modeling of blood biochemistry revealed that maximum ambient temperature during recapture was associated with a stress leukogram (7–26% decline in percent lymphocytes, 12–21% increase in percent neutrophils) and maximum duration of helicopter operations had a similar but smaller effect. We conclude that polar bear activity and body temperature during helicopter capture are similar to that which occurs during the most intense events of natural behavior; high body temperature, especially in warm capture conditions, is a key concern; additional study of stress leukograms in polar bears is needed; and additional data collection regarding capture operations would be useful.     

Anesthesia of wild red howler monkeys (Alouatta seniculus) with medetomidine/ketamine and reversal by atipamezole

Wild red howler monkeys (Alouatta seniculus) were translocated during the flooding of the forest at a hydroelectric dam site in French Guiana. For a variety of minor clinical procedures, 96 monkeys were anesthetized with various intramuscular injections of combinations of medetomidine and ketamine. The howler population was composed of healthy animals (42 males and 54 females) of various ages. Medetomidine (150 μg/kg) associated with ketamine (4 mg/kg) gave the best results and was used on 63 animals. The injection rapidly resulted in complete immobilization with good to excellent myorelaxation. The induction stage was quiet, with absence of both corneal and pedal withdrawal reflexes in 57 animals after 2.9 ± 1.4 min. Six animals required an additional injection. Rectal temperature and respiratory and heart rates decreased during anesthesia, whereas relative oxyhemoglobin saturation increased. One death occurred during anesthesia. One abortion and one death also occurred the day following anesthesia but were more probably a result of capture stress. Atipamezole given i.m. at a dose of five times the medetomidine dose 38.4 ± 8.0 min after the anesthetic injection led to standing recovery in 7.1 ± 4.5 min. Spontaneous recovery occurred in 17 animals before the atipamezole injection after an average of 30.6 ± 9.6 min. Total recovery time was shorter in young animals. Medetomidine/ketamine induced good myorelaxation and provided considerably shortened immobilization duration, which are two notable advantages for field studies. We recommend this association for short procedures including minor surgery in red howler monkeys. Am. J. Primatol. 45:399–410, 1998. © 1998 Wiley-Liss, Inc.     

The chemical restraint of apes and monkeys by means of phencyclidine or ketamine.

The anesthetic effects of two drugs, namely, Phencyclidine and Ketamine, used alone or in combination with atropine, were compared during clinical and experimental procedures on different primate species ranging from gorillas, orangutans, white-faced and dwarf chimpanzees, baboons, cercopithecus monkeys to new--world monkeys. It is concluded that both these anesthetics are very good and safe drugs for restraint and anesthesia. Ketamine appeared to be superior to Phencyclidine for use among apes and monkeys in so far as it is shorter acting, has wider safety margin and shorter recovery time, provides better muscle relaxation and is practically without side effects. But Phencyclidine has definite advantage in so far as it is needed is smaller quantity to produce comparable effect of anesthesia.     

Effect of preparation technique on the properties and in vivo efficacy of benzocaine-loaded ethosomes

This study aimed to investigate the influence of the preparation conditions on the performance of an ethosomal formulation for topical delivery of the local anesthetic agent, benzocaine (BZC). Ethosomes were prepared with different techniques, such as thin-layer evaporation, freezing and thawing, reverse-phase evaporation, extrusion and sonication, obtaining, respectively, multilayer vesicles (MLVs), frozen and thawed MLV (FATMLV), large unilamellar vesicles (LUVs), and small unilamellar vesicles (SUVs). The obtained vesicles were characterized for morphology, size, zeta potential, and entrapment efficiency (EE%), and their stability was monitored during storage at 4°C. In vitro permeation properties from gels incorporating drug ethosomal dispersions were evaluated in vitro by using artificial lipophilic membranes, while their anesthetic effect was determined in vivo on rabbits. The results suggested that the vesicle preparation method plays an important role in affecting the properties and effectiveness of ethosomal formulations. MLVs and LUVs exhibited higher drug EE% and better stability than FATMLV and SUV vesicles. The In vitro drug permeation rate was directly related to the vesicle EE% and varied in the order MLV>LUV≈FATMLV>SUV. The therapeutic efficacy of BZC ethosomal formulations was significantly improved with respect to the corresponding BZC solution. The best results, in terms of enhanced intensity of anesthetic effect, were given by formulations containing MLVs and LUVs, and the order of effectiveness was MLV≈LUV>FATMLV≈SUV, rather similar to that found in permeation studies. On the contrary, unexpectedly, the effectiveness order in increasing the duration of drug action was SUV≥MLV>LUV≈FATMLV. The highest efficacy of SUVs was probably due to the more intimate contact with the epithelium due to their greatest surface area, which allowed the longest extension of drug therapeutic action. The overall results suggest that a suitably developed ethosomal formulation of BZC can be of actual value for improving its clinical effectiveness in topical anesthesia.     

A Pharmacokinetics-Neural Mass Model (PK-NMM) for the Simulation of EEG Activity during Propofol Anesthesia

Modeling the effects of anesthetic drugs on brain activity is very helpful in understanding anesthesia mechanisms. The aim of this study was to set up a combined model to relate actual drug levels to EEG dynamics and behavioral states during propofol-induced anesthesia. We proposed a new combined theoretical model based on a pharmacokinetics (PK) model and a neural mass model (NMM), which we termed PK-NMM—with the aim of simulating electroencephalogram (EEG) activity during propofol-induced general anesthesia. The PK model was used to derive propofol effect-site drug concentrations (C _eff) based on the actual drug infusion regimen. The NMM model took C _eff as the control parameter to produce simulated EEG-like (sEEG) data. For comparison, we used real prefrontal EEG (rEEG) data of nine volunteers undergoing propofol anesthesia from a previous experiment. To see how well the sEEG could describe the dynamic changes of neural activity during anesthesia, the rEEG data and the sEEG data were compared with respect to: power-frequency plots; nonlinear exponent (permutation entropy (PE)); and bispectral SynchFastSlow (SFS) parameters. We found that the PK-NMM model was able to reproduce anesthesia EEG-like signals based on the estimated drug concentration and patients’ condition. The frequency spectrum indicated that the frequency power peak of the sEEG moved towards the low frequency band as anesthesia deepened. Different anesthetic states could be differentiated by the PE index. The correlation coefficient of PE was 0.80±0.13 (mean±standard deviation) between rEEG and sEEG for all subjects. Additionally, SFS could track the depth of anesthesia and the SFS of rEEG and sEEG were highly correlated with a correlation coefficient of 0.77±0.13. The PK-NMM model could simulate EEG activity and might be a useful tool for understanding the action of propofol on brain activity.     

Physiological,pharmacokinetic and liver metabolism comparisons between 3-, 6-, 12- and 18-month-old male Sprague Dawley rats under ketamine-xylazine anesthesia

The main objective of this study was to compare the physiological changes (withdrawal and corneal reflexes, respiratory and cardiac frequency, blood oxygen saturation, and rectal temperature) following intraperitoneal administration of ketamine (80 mg/kg) and xylazine (10 mg/kg) to 3-, 6-, 12- and 18-month-old male Sprague Dawley rats (n=6/age group). Plasma pharmacokinetics, liver metabolism, and blood biochemistry were examined for a limited number of animals to better explain anesthetic drug effects. Selected organs were collected for histopathology. The results for the withdrawal and corneal reflexes suggest a shorter duration and decreased depth of anesthesia with aging. Significant cardiac and respiratory depression, as well as decreased blood oxygen saturation, occurred in all age groups however, cardiac frequency was the most affected parameter with aging, since the 6-, 12-, and 18-month-old animals did not recuperate to normal values during recovery from anesthesia. Pharmacokinetic parameters (T_1/2 and AUC) increased and drug clearance decreased with aging, which strongly suggests that drug exposure is associated with the physiological results. The findings for liver S9 fractions of 18-month-old rats compared with the other age groups suggest that following a normal ketamine anesthetic dose (80 mg/kg), drug metabolism is impaired, leading to a significant increase of drug exposure. In conclusion, age and related factors have a substantial effect on ketamine and xylazine availability, which is reflected by significant changes in pharmacokinetics and liver metabolism of these drugs, and this translates into shorter and less effective anesthesia with increasing age.     

Effects of an anesthetic mixture of medetomidine,midazolam, and butorphanol in rats—strain difference and antagonism by atipamezole

An anesthetic mixture of medetomidine (MED), midazolam (MID), and butorphanol (BUT) has been used in laboratory animals. We previously reported that this anesthetic mixture produced closely similar anesthetic effects in BALB/c and C57BL/6J strains. We also demonstrated the efficacy of atipamezole (ATI), an antagonist of MED that produced quick recovery from anesthesia in mice. Anesthetics have various anesthetic effects among animal strains. However, the differences in the effects of anesthetic mixtures in rats are unclear. In the present study, we first examined effects of the abovementioned anesthetic mixture using three different rat strains: Wistar (WST), Sprague-Dawley (SD), and Fischer 344 (F344). Second, we examined how different dosages and optimum injection timing of ATI affected recovery from anesthesia in rats. We used the anesthetic score to measure anesthetic duration and a pulse oximeter to monitor vital signs. We found no significant differences in anesthetic duration among the three different strains. However, recovery from anesthesia in the SD strain took significantly longer than in the other strains. The antagonistic effects of ATI (0.15 mg/kg and 0.75 mg/kg) were equivalent when administered at 30 min after anesthetic mixture administration. The antagonistic effects of ATI 0.75 mg/kg were stronger than those of ATI 0.15 mg/kg at 10 min after anesthetic mixture administration. This anesthetic mixture is a useful drug that can induce similar anesthetic effects in three different strains and has an antagonist, ATI, that makes rats quickly recover from anesthesia. These results may contribute to the welfare of laboratory animals.     

Essential oil of Lippia alba as a sedative and anesthetic for the sea urchin Echinometra lucunter (Linnaeus, 1758)

The sea urchin, Echinometra lucunter, is consumed in restaurants in Europe and Asia for high prices. This study evaluated the use of the essential oil of Lippia alba (EOL) as a sedative and anesthetic in this sea urchin. Different EOL concentrations were tested (50, 100 and 150 μL L^?1), in addition to a group that received ethanol and a control group. After the anesthesia and recovery from the different treatments, the coelomic fluid, gonads and intestine were collected for the analysis of oxidative stress parameters. The highest concentration tested (150 μL L^?1) was determined to be the optimal concentration for anesthesia. Results suggest that EOL improved the response to oxidative stress, since a lower level of thiobarbituric acid-reactive substances and greater superoxide dismutase and catalase activities were observed in the coelomic fluid and E. lucunter gonads, making the EOL a promising anesthetic for sea urchins.     

Optimization of conscious sedation in plastic surgery.

The administration of conscious sedation by the plastic surgeon must be safe, efficient, and consistent. In the proper setting, with trained staff and appropriate backup, conscious sedation can allow optimal patient satisfaction with expedient recovery in addition to cost containment. The highly effective local anesthesia afforded by dilute, high-volume ("tumescent") infiltration extends the use of conscious sedation to cases previously performed under general anesthesia or deep sedation. The purpose of this analysis was to identify variables in conscious sedation that affect traditional outcome parameters in ambulatory surgery, particularly the duration of recovery and adverse events such as nausea and emesis. All perioperative and operative records of 300 consecutive patients having plastic surgical procedures under conscious sedation were carefully reviewed. Patients were ASA class I or II by requisite. Conscious sedation followed a standardized administration protocol, using incremental doses of two agents: midazolam (0.25 to 1 mg) and fentanyl (12.5 to 50 mcg). A subset of patients received preoperative oral sedation. Multivariate statistical analysis was conducted using SPSS 8.0 for Windows (SPSS Inc., Chicago, Ill.). Of the 300 patients, same-day discharge was intended for 281. Eight procedure categories were defined. No anesthetic complications occurred. As expected, recovery time was significantly correlated with the duration and type of procedure (p < 0.001) and the total dosage of both intraoperative sedative agents (p < 0.001). Interestingly, a negative correlation with advancing age existed (p < 0.001), likely reflecting the significantly higher intraoperative sedative dosing in younger patients (p < 0.001). When controlled for the effects of procedure duration and intraoperative sedative dosing, two other variables-use of preoperative oral sedation and postoperative nausea/emesis-significantly lengthened recovery time (p = 0.0001 for each). Fifteen unintended admissions occurred secondary to nausea, prolonged drowsiness, or pain control needs. Conscious sedation is an effective anesthetic choice for routine plastic surgical procedures, many of which would commonly be performed under general anesthesia. In our experience with a carefully structured and controlled conscious sedation protocol, the technique has proven to be safe and effective. This analysis of outcome parameters identified two important and potentially avoidable causes of recovery delay following conscious sedation-oral premedication and nausea/emesis. Nausea and emesis were particularly problematic in that they were responsible for 11 of 15 (73 percent) unintended admissions. Preoperative sedation is valuable in certain circumstances, and its use is not discouraged; however, its benefits must be weighed against its unwanted effects, which can include a prolongation of recovery.     

Evaluation of isoflurane and propofol anesthesia for intraabdominal transmitter placement in nesting female canvasback ducks

Heart rate, occurrence of apnea, body temperature, quality of anesthesia and nest abandonment were compared during either propofol or isoflurane anesthesia of nesting female canvasback ducks (Aythya valisineria) at 15 to 18 days of incubation. One hundred eighteen canvasbacks were assigned randomly to three treatments so that nest abandonment could be compared among treatments from May to July 1995 and 1996. Sterile dummy silicone implants were placed during an abdominal laparotomy while ducks were anesthetized with either propofol or isoflurane, or ducks were flushed from the nest but not captured (control). Propofol was delivered through an intravenous catheter, while isoflurane was delivered in oxygen. Propofol provided smooth, rapid induction and recovery, whereas ducks recovering from isoflurane tended to struggle. At the nest, ducks in the propofol group were given additional boluses until they were lightly anesthetized, whereas birds that received isoflurane were released. All birds survived surgery but one death occurred prior to surgery in 1995 using propofol during a period without ventilation and monitoring. Adequate artificial ventilation is recommended to prevent complications. Heart rate declined significantly in both years during isoflurane anesthesia and in 1995 during propofol anesthesia but not 1996. During both isoflurane and propofol anesthesia, body temperature declined significantly over time. Nest abandonment was significantly different among treatments and occurred in all treatment groups in both years, but propofol (15%) and control groups (8%) had lower than expected abandonment compared to isoflurane (28%). Propofol offers several advantages over isoflurane for field use; equipment is easily portable, lower anesthetic cost, and ambient temperature does not alter physical characteristics of the drug. Advantages over isoflurane, including lower nest abandonment following intraabdominal radio transmitter placement, make propofol a good anesthetic choice for field studies.     

硬膜外复合全麻对老年高血压患者腹部手术后并发症的影响

目的：探讨硬膜外复合全麻对老年高血压患者腹部手术后并发生的影响。方法：收集2013 年6 月-2015 年6 月在两家医院 接受腹部手术的老年高血压患者100 例,根据麻醉方法不同分为研究组和对照组。研究组患者给予硬膜外复合麻醉,对照组给予 全凭静脉麻醉。观察并比较两组患者的麻醉时间、药物用量以及术后并发症的发生率。结果：两组麻醉时间比较,差异无统计学意 义（P>0.05）;研究组麻醉药物用量低于对照组,差异具有统计学意义（P<0.05）;两组患者手术时间比较,差异无统计学意义（P>0. 05）;研究组患者术后苏醒时间、拔管时间以及住院时间均短于对照组,差异具有统计学意义（P<0.05）;研究组术后并发症的发生 率低于对照组,差异具有统计学意义（P<0.05）。结论：硬膜外复合全麻用于老年高血压患者腹部手术能够减少麻醉药物用量,降低 术后并发症的发生率,安全性较高。     

TRIFLUOROETHYLVINYL ETHER (FLUOROMAR?)—A Preliminary Report on Clinical Experience and Animal Experiment

In observations of 80 cases in which Fluoromar was used for inhalation anesthesia it was noted that induction was rapid; maintenance although labile, was usually smooth; and recovery of reflexes was rapid. Anesthetic complications were minimal, and postanesthetic complications were limited to nausea and vomiting in no greater incidence than that expected to follow the use of most inhalation anesthetic agents.Fluoromar produces rapid, and not particularly unpleasant, loss of consciousness, and will produce complete anesthesia without supplement. However, the muscular relaxation afforded by Fluoromar is not complete, and delayed recovery from anesthesia may follow attempts to produce relaxation by deepening too greatly the level of anesthesia.The inflammability of Fluoromar is less than that of other inhalation agents.     

Trifluoroethylvinyl ether (fluoromar); a preliminary report on clinical experience and animal experiment

In observations of 80 cases in which Fluoromar was used for inhalation anesthesia it was noted that induction was rapid; maintenance although labile, was usually smooth; and recovery of reflexes was rapid. Anesthetic complications were minimal, and postanesthetic complications were limited to nausea and vomiting in no greater incidence than that expected to follow the use of most inhalation anesthetic agents. Fluoromar produces rapid, and not particularly unpleasant, loss of consciousness, and will produce complete anesthesia without supplement. However, the muscular relaxation afforded by Fluoromar is not complete, and delayed recovery from anesthesia may follow attempts to produce relaxation by deepening too greatly the level of anesthesia. The inflammability of Fluoromar is less than that of other inhalation agents.     

Physiological and Behavioral Effects of Capture Darting on Red Colobus Monkeys (Procolobus rufomitratus) with a Comparison to Chimpanzee (Pan troglodytes) Predation

Understanding how human activities affect wild primates is critical to the design of effective conservation strategies. Despite this need, few studies have examined the physiological and behavioral effects of field research methods in the wild. Here, we examine how the stress response, i.e., fecal cortisol, and behavior of Ugandan red colobus monkeys (Procolobus rufomitratus) in Kibale National Park are affected by chemical immobilization and collaring, i.e., capture. We compare this anthropogenic stressor to a naturally occurring stressor: a chimpanzee (Pan troglodytes) predation attack. Two adult males had peak cortisol levels of 283 and 284 ng/g 2–3 d after capture, which were 190% and 182% above their baseline levels, i.e., the first sample taken immediately after capture, but these peak levels did not remain elevated. Using long-term data, i.e., 11 mo of data, we found no difference in fecal cortisol levels between 10 darted and collared individuals and 14 individuals living in the same social group that were not darted or collared. For the chimpanzee attack, peak fecal cortisol levels (147–211% above baseline) were recorded 1–4 d after the attack, but these levels also did not remain elevated for long. These data show that darting and collaring and a chimpanzee predation attempt caused an acute stress response, but neither leads to sustained elevated cortisol levels. Thus, in situations in which research contributes significantly to the conservation of primates and cannot be conducted noninvasively, capture darting appears to be a useful technique with minimal long-term effects as long as injury and mortality are avoided. However, we encourage researchers to make similar physiological and behavioral comparisons in other field studies using similar techniques to provide a better understanding of the effects of research practices on the stress physiology and social behavior of wild primates.