The dromedary camel (Camelus dromedaries) has not existed in the wild for 2,000 years, having been widely domesticated beginning approximately 3,500 years ago. Their native range includes areas of the Middle East through northern India and desert regions in northern Africa, where they are still found in abundance. They were also introduced to central Australia during the 19th Century for the purposes of exploration. Approximately 90% of the world's camels are dromedary camels, and nearly all of these are domesticated.
Despite their high level of domestication, research, zoos and management programs can require the capture and manipulation of dromedary camels. The development of non- and minimally invasive procedures over the years have allowed researchers, veterinarians and management personnel to obtain certain types of data without the need to handle animals. Some information, however, can only be obtained by capturing animals.1
Technological advances such as global positioning system (GPS) collars, heat sensitive transmitters and advanced physiological monitoring equipment now allow detailed research on species such as dromedary camels, but still require the initial capture and manipulation of individual animals.2
The dromedary camel differs from its cousins the Bactrian camel (C. bactrianus) and the wild Bactrian camel (C. ferus) in that the former has only one hump, while the latter two have two humps. The camel’s hump is composed of fat and fibrous tissue, which the animal draws upon as a food reserve in times of need.3
All three camel species are approximately 10 feet long and 6-1/2 feet high at the hump. Males typically weigh in at approximately 900 to 1,400 pounds; females are about 10% smaller and lighter. Their color is light brown to medium gray. Bactrian camels are slightly darker and stockier, and have more hair than wild Bactrian camels or dromedary camels.4 Dromedary camels, also called Arabian camels, have been long valued as pack animals that can carry large loads (over 100 lbs.).4 They have also been used by humans for their wool, milk, meat and leather.5
Dromedary camels are diurnal and spend much of their days eating. Their upper lips are split in half, with each half moving independently. This allows them to forage very near to the ground. Their lips can break off and eat tough vegetation, and it has been reported that some camels will even eat fish.5 Camels can go a week or more without water, and can last for several months without food. The humps on their backs store up to 80 pounds of fat, which they break down into energy when food is not available.4,5 When camels do drink water, they can consume 30 gallons of in less than 15 minutes without ill effects.
Dromedary camels are seasonal breeders with females coming into heat during the breeding season. This normally occurs during the winter months, from November to March.3
The effects of immobilization on dromedary camels can differ depending upon the capture methodology employed. The published research agrees that captures by remote delivery of immobilizing drugs via darting lower an camel’s stress levels, thus decreasing the subsequent capture effects as compared to other techniques.6 This is a chief reason why chemical immobilization is becoming a preferred capture method, particularly in the case of large mammals such as camels.
The three classes of immobilization drugs that are used to immobilize dromedary camels include opioids, cyclohexamines and neuroleptics.
Opioids
Cyclohexamines
Neuroleptics
In a zoo setting, less stress on dromedary camels is likely to occur than in the field, as zoo animals tend to be far more acclimatized to humans and procedures. Additionally, since camels have been so heavily domesticated, most are less prone to capture stress than other hoofstock species.
Intramuscular hand injection can be used when working with camels that are cooperative. When hand injecting, rapid delivery while minimizing risk to the handler or animal is essential. Pole syringes are also widely used for this purpose; these afford greater distance than approaching an animal for a hand injection without resorting to remote delivery systems. Drug delivery by pole syringe requires manual injection follow through to administer the drug, since the handle is essentially an extension of the plunger. As with hand injection, larger bore needles should be used to ensure complete drug delivery.
Remote drug delivery is usually carried out by approaching the camel and shooting a dart from a helicopter, an off-road vehicle or from the ground. While this can significantly reduce stress compared to physical capture methods, it still impacts the camel’s stress levels. A frightened camel will have an increased heart rate, higher levels of cortisol and other stress-related biochemicals.6 An approach on foot tends to produce even lower stress levels in dromedary camels, because animals are generally less frightened than if a noisy vehicle is used.
Intubation is recommended for camels that need to be anesthetized for longer than 20 minutes. Analgesia will be required if the camel’s skin has been breached by anything larger than a hypodermic needle, including biopsy instruments. Invasive surgeries should be conducted using general anesthetics with the animal at a surgical plane; intraoperative analgesia that continues after anesthetic recovery should be provided in some form to every surgical patient.1 For analgesic drugs, doses and frequencies of administration are more difficult to gauge, even with close clinical observation for discomfort.7 These observations can be even more difficult to make in the field than in a clinic or zoo setting, compounding the difficulty in such assessments.
Most of the opioid analgesics (Buprenorphine, Fentanyl, Butorphenol, Oxymorphone, etc.) will not be effective after 12 hours after administration. Longer‐lasting, non‐steroidal anti‐inflammatory analgesics (NSAIDs) such as Meloxicam, Carprofen, Flunixin, Ketoprofen,etc. have longer durations of action than opioids, and can be administered in conjunction with opioids to increase potency of effect and duration of action.7
Reversal agents are often required to neutralize sedation or anesthetic agents, whether general anesthesia or sedation has been used. These allow animals to completely recover from being anesthetized, as opposed to metabolizing the immobilizing agents over time. This is even more important in the field than in a clinic or zoo setting, because a chemically-compromised animal will be in danger of injury and other hazards.
Due to the variety of factors that influence duration of anesthesia, the literature maintains that anesthetic drugs should always be titrated to effect. If anesthesia is being maintained by a gas anesthetic (e.g., isoflurane), titration of anesthetic depth can be controlled almost immediately by adjusting the amount of anesthetic gas being administered to the animal. In addition, anesthetic duration can be extended for as long as the anesthetic gas is administered.7
On the other hand, injectable anesthetics and sedatives do not have this flexibility. Once a dose has been administered, it cannot be “un-administered” to facilitate the end of anesthesia to coincide with the end of the procedure.8 In such cases, reversal drugs are used to bring about the desired effect.
Atipamezole is a synthetic α2-adrenergic antagonist. Developed to reverse the actions of compounds such as medetomidine and dexmedetomidine, atipamezole safely and reliably reverses the effects of these compounds and is widely used in small and large animal practices, as well as in wildlife applications.9
Naltrexone hydrochloride is an opioid receptor antagonist that is used in veterinary medicine to block receptors as a reversal agent for opiate agonists such as butorphanol.
Today, the drug formulations available for chemical immobilization have been refined to a degree that eliminates much of the risk that existed years ago. With the right drug formulations, proper planning and safety precautions in place, experienced personnel can have the expectation of effective and incident-free chemical immobilization of dromedary camels.
1Brivio F, Grignolio S, Sica N, Cerise S, Bassano B (2015) Assessing the Impact of Capture on Wild Animals: The Case Study of Chemical Immobilisation on Alpine Ibex. PLoS ONE 10(6): e0130957.
2Powell RA, Proulx G (2003) Trapping and marking terrestrial mammals for research: integrating ethics, performance criteria, techniques, and common sense. ILAR J 44: 259–276.
3animaldiversity.org.
4nationalgeographic.com.
5spana.org.
6Arnemo, Jon & Kreeger, Terry. (2018). Handbook of Wildlife Chemical Immobilization 5th Ed.
7Nielsen, L. Chemical Immobilization of Wild and Exotic Animals. (1999) Ames, Iowa, Iowa State University Press.
8Lance, W. Exotic Hoof Stock Anesthesia and Analgesia: Best Practices. In: Proceedings, NAVC Conference 2008, pp. 1914-15.
9Ball, L. Camel Anesthesia. Wiley Online Library, 25 July 2014.