Behind the Scenes: Caring for the Zoo’s Most Dangerous Patients

As the Zoological Society of London celebrates its 200th anniversary this spring, Guardian photographer David Levene has documented a year following the charity’s specialist animal doctors, capturing the remarkable difficulties of caring for some of the world’s most dangerous and endangered animals. From anaesthetising a king cobra that reacted to sedation with a toxic discharge to assessing an Asiatic lion’s unusually narrow ear canal, the vets, nurses and specialists working across ZSL’s facilities in London and Whipsnade manage medical emergencies that few other professionals ever face. With only a handful of British zoos employing their own in-house veterinarians, ZSL’s five-strong veterinary team, six nurses, a animal pathologist and several specialists constitute a unique form of veterinary knowledge—one that has pioneered standards in animal care for two centuries.

A Year of Exceptional Healthcare Difficulties

David Levene’s year-long photographic project uncovered the unpredictable nature of zoo animal medicine. On his second visit, the photographer found himself face-to-face with Bhanu, an Asiatic lion afflicted with persistent recurring ear infections that had left him with an exceptionally constricted ear canal. The condition required a general anaesthetic—always a last resort in zoo medicine—so the animal care specialists could perform a comprehensive assessment. Whilst Bhanu was under sedation, the vets took the chance to perform detailed health assessments, encompassing careful examination of his teeth, which are essential for a carnivore’s survival and wellbeing in captivity.

Perhaps the most striking moment came when King Arthur, a young king cobra and the world’s longest venomous snake, received his anaesthetic injection. The reptile responded to the sedative with typical aggression, rearing up and spitting directly at Levene through the protective glass barrier. “I was the first person he saw after he’d been jabbed in the tail,” Levene recalls with wry humour. One bite from the young snake could prove fatal to an elephant, yet the ZSL team handles such exceptionally perilous patients with practised precision and unwavering professionalism.

• King cobra displays anaesthetic with venom-spraying display
• Asiatic lion demands sedation for ear canal examination
• Veterinary team performs multiple health checks during anaesthesia
• Zoo medicine calls for expertise with exotic and hazardous species

The Professionals That Maintain Endangered Species Alive

The veterinary team at ZSL constitutes one of Britain’s most specialised medical workforces. With five certified veterinarians, six nursing staff, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity maintains what few UK zoos can provide: a comprehensive, in-house medical facility. This multidisciplinary approach allows the team to tackle the complicated medical requirements of creatures extending from dormice to rhinoceroses. Each specialist brings crucial expertise, whether diagnosing obscure parasitic infections, studying genetic material or performing intricate surgical procedures on animals worth millions to global conservation efforts.

The obstacles these experts encounter are distinctly exceptional. Shifting a unconscious rhino requires thorough planning and specialist equipment. Sedating a dormouse demands precise dosing for an animal weighing mere grams. Treating a venomous snake requires comprehending its behaviour and physiology in ways that relatively few veterinarians experience. The ZSL team must constantly adapt their methods, leveraging extensive accumulated knowledge whilst modifying their methods to each animal. Their work extends far beyond routine check-ups; they are stewards of some of the Earth’s endangered species, where a lone animal’s survival can carry significant ecological implications.

From Original Innovators to Contemporary Medicine

ZSL’s commitment to the welfare of animals dates back two centuries. The journals of Charles Spooner, the zoo’s first “medical attendant,” provide some of the earliest written evidence of veterinary care in Britain. Spooner cared for a young cub named Nelson affected by mange infection, teething troubles and a life-threatening ulcer on his lower jaw. Through careful treatment—lancing the ulcer and giving daily doses of zinc sulphate—Spooner preserved the cub’s life, establishing a tradition of compassionate and innovative veterinary care that persists today.

This longstanding foundation has influenced modern ZSL veterinary practice. The principles Spooner pioneered—careful examination, resourceful approaches and steadfast commitment to individual animals—remain core to the team’s approach. Over two centuries, ZSL vets have continually advanced boundaries in animal health and welfare, publishing research and developing techniques now adopted globally. As the zoo celebrates its bicentenary, its veterinary team stands as a living testament to two hundred years of groundbreaking achievement in exotic animal medicine.

Surgical Precision on the Earth’s Rarest Animals

Every surgical procedure undertaken at ZSL represents a calculated risk with far-reaching significant consequences. When a vet performs surgery on an endangered animal, they are not simply caring for a single creature—they are protecting an entire population whose continued existence could rely on that one individual. The team must weigh the need to act with the fundamental risks of anaesthesia, infection and operative setbacks. Each choice draws upon by decades of accumulated knowledge, joint investigations with overseas specialists, and an deep knowledge of the individual’s clinical background and unique characteristics.

The intricacy escalates dramatically when handling creatures whose physical structure varies considerably from tame species. A rhino’s circulatory system reacts unpredictably to anaesthetic administration. A snake’s metabolism processes anaesthetic agents at rates that exceed conventional guidelines. A dormouse’s diminutive physique leaves almost no room for error in drug dosing. The ZSL veterinary experts has established bespoke methods and observation technology to address these difficulties, often establishing innovative techniques that later become established protocol across zoo facilities worldwide.

• Anaesthetising dormice requires accurate micrograms of meticulously formulated pharmaceutical solutions.
• King cobras demand safe housing protocols during recovery from sedation procedures.
• Rhino relocations necessitate expert-level gear and coordinated multi-team operations.
• Dental examinations on carnivores reveal key markers of general wellbeing.
• Post-operative monitoring involves 24-hour watchful care by specialist animal care staff.

The Emotional Connection Between Animal Carers and Creatures

Behind every effective medical intervention lies a deep relationship between caregiver and animal. Zookeepers like Tara Humphrey devote extensive time observing their animals, recognising subtle behavioural shifts that signal illness or discomfort. When Bhanu the Asiatic lion was put under anaesthetic for his ear examination, Humphrey took the uncommon chance for tactile contact, cuddling the impressive animal whilst he lay asleep. These connections go beyond mere emotion; they represent the deep knowledge that allows keepers to provide crucial information to veterinarians, ultimately enhancing accuracy of diagnosis and treatment outcomes.

The Science of Anaesthetizing Big and Potentially Dangerous Wildlife

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinarians’ most critical duties. Unlike routine procedures at traditional veterinary clinics, anaesthetising a lion, rhino, or king cobra demands careful preparation, specialised apparatus, and unwavering composure. The stakes are exceptionally significant: miscalculate the dosage for a 2-tonne rhinoceros and the animal’s cardiovascular system may fail; give insufficient medication to a venomous snake and the keeper encounters real risk of death. ZSL’s veterinarians have devoted years developing procedures that take into account each animal’s unique physiology, body composition, and metabolic peculiarities.

The procedure begins long before the syringe enters flesh. Veterinarians examine the individual animal’s medical history, consult with overseas experts, and determine standard physiological measurements. They position themselves strategically, ensuring quick availability to emergency equipment in case problems develop. Once the anaesthetic takes effect, constant observation grows essential. Pulse, arterial tension, oxygen saturation, and body temperature are tracked relentlessly. Post-operative phases demand equally vigilant observation, as animals emerging from sedation can behave unpredictably—as Guardian photographer David Levene discovered when King Arthur the cobra rose up and spat directly at him, despite the protective glass barrier.

Training the Future of Zoo Veterinarians

The skills needed to treat threatened animals at ZSL doesn’t materialise overnight. Aspiring zoo veterinarians undergo years of rigorous training, beginning with conventional veterinary qualifications before focusing in exotic and wild animal medicine. ZSL’s strong reputation attracts talented professionals from across the globe, many of whom complete apprenticeships and mentorships under the organisation’s experienced team. This hands-on education proves invaluable; textbook knowledge alone cannot prepare a vet for the unpredictability of sedating a lion or identifying illness in a critically endangered species where each animal matters greatly to conservation efforts.

The veterinary team at ZSL actively contributes in career advancement within the zoo sector, sharing their accumulated knowledge through peer-reviewed articles, industry conferences, and joint research initiatives. Young veterinarians gain valuable experience through involvement with diverse cases—from routine health checks to emergency interventions—whilst working with specialists in pathology, microbiology, and molecular diagnostics. This cross-functional setting drives advancement in veterinary medicine and ensures that junior veterinarians understand the wider implications of zoo medicine: balancing immediate creature wellbeing with long-term conservation goals and contributing to scientific understanding of species preservation.

• Training with experienced ZSL veterinarians with expertise in exotic animal care and urgent intervention
• Exposure to cutting-edge diagnostic tools and laboratory facilities for applied training
• Engagement in international research collaborations improving veterinary care standards for zoos
• Exposure to a wide range of species demanding tailored medical approaches and conservation-focused treatment strategies