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

As the Zoological Society of London marks its 200th anniversary this spring, Guardian photographer David Levene has captured a year spent shadowing the charity’s specialist animal doctors, capturing the remarkable difficulties of caring for some of the world’s most dangerous and endangered animals. From sedating a king cobra that responded to anaesthetic with a toxic discharge to examining an Asiatic lion’s distinctly constricted ear canal, the vets, nurses and specialists working across ZSL’s London and Whipsnade zoos manage medical emergencies that most other medical practitioners ever face. With just a small number of British zoos employing their own resident vets, ZSL’s team of five vets, nursing staff of six, a 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 extended photo documentation uncovered the unpredictability of zoo animal medicine. On his second visit, the documentarian encountered Bhanu, an Asiatic lion afflicted with chronic recurrent ear infections that had left him with an unusually narrow ear canal. The condition necessitated a full anaesthetic—always a final option in zoo medicine—so the animal care specialists could conduct a thorough examination. Whilst Bhanu was sedated, the vets took the chance to perform detailed health assessments, encompassing careful examination of his teeth, which are absolutely crucial 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, was given his anaesthetic injection. The reptile reacted to the sedative with characteristic aggression, rearing up and spitting directly at Levene through the protective glass barrier. “I was the first person he saw after he’d been injected 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 practiced care and unwavering professionalism.

• King cobra reacts to anaesthetic with venom-spraying display
• Asiatic lion demands sedation for aural examination
• Veterinary team performs several health assessments during anaesthesia
• Zoo medicine requires expertise with exotic and hazardous species

The Experts Who Keep At-Risk Animals Thriving

The veterinary staff at ZSL exemplifies one of Britain’s most specialist medical workforces. With five certified veterinarians, six veterinary nurses, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity operates what few British zoos can replicate: a comprehensive on-site medical facility. This multidisciplinary model enables the team to tackle the intricate health demands of creatures ranging from dormice to rhinoceroses. Each specialist contributes vital skills, whether detecting rare parasitic infections, studying genetic material or performing intricate surgical procedures on animals worth millions to global conservation efforts.

The obstacles these experts face are distinctly exceptional. Moving a sedated rhino demands careful planning and advanced apparatus. Sedating a dormouse requires precise dosing for an animal weighing mere grams. Treating a venomous snake demands understanding its behaviour and physiology in ways that few veterinarians come across. The ZSL group continually needs to innovate, utilising decades of accumulated knowledge whilst modifying their techniques to individual animals. Their work goes well past routine check-ups; they are guardians of some of the Earth’s endangered species, where a lone animal’s survival can hold significant ecological implications.

From Early Pioneers to Modern Healthcare

ZSL’s dedication to the welfare of animals extends back 200 years. The journals of Charles Spooner, the zoo’s original “medical attendant,” give some of the first written accounts of veterinary care in Britain. Spooner managed a young cub named Nelson suffering from mange, dental issues and a potentially fatal ulcer on his lower jaw. Through careful treatment—opening the ulcer and giving regular zinc sulphate treatments—Spooner saved the cub’s life, creating a record of compassionate and innovative veterinary care that continues today.

This enduring foundation has shaped modern ZSL veterinary practice. The principles Spooner pioneered—meticulous observation, creative problem-solving and resolute devotion to individual animals—remain central to the team’s approach. Over two centuries, ZSL vets have regularly extended boundaries in veterinary care and animal welfare, publishing research and developing techniques now adopted globally. As the zoo marks its bicentenary, its veterinary team stands as a lasting tribute to two hundred years of groundbreaking achievement in exotic animal medicine.

Precise Surgical Intervention on the Earth’s Rarest Species

Every surgical operation performed at ZSL represents a calculated risk with far-reaching significant consequences. When a vet performs surgery on an species at risk, they are not simply treating an individual patient—they are safeguarding a species whose survival may depend on that one individual. The team must balance the imperative to intervene with the fundamental risks of anaesthesia, infection and surgical complications. Each decision is informed by decades of accumulated knowledge, joint investigations with international colleagues, and an deep knowledge of the specific animal’s medical history and individual quirks.

The intricacy increases substantially when working with creatures whose physical structure deviates substantially from domestic livestock. A rhino’s cardiovascular system reacts unpredictably to sedative drugs. A snake’s metabolism breaks down anaesthetic agents at rates that exceed conventional guidelines. A dormouse’s diminutive physique leaves scarcely any allowance for error in drug dosing. The ZSL veterinary staff has developed bespoke methods and observation technology to overcome these obstacles, often developing novel methods that subsequently become established protocol across zoo facilities worldwide.

• Anaesthetising dormice requires precise micrograms of carefully calculated pharmaceutical solutions.
• King cobras demand secure containment protocols during recovery from sedation procedures.
• Rhino relocations necessitate specialist equipment and coordinated multi-team operations.
• Dental examinations on carnivores reveal crucial indicators of overall health status.
• Post-operative monitoring involves round-the-clock observation by experienced veterinary support staff.

The Deep Bond Between Keepers and Animals

Behind every effective medical procedure lies a profound relationship between caregiver and creature. Zookeepers like Tara Humphrey devote extensive time observing their charges, identifying minor changes in behaviour that indicate illness or distress. 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 bonds transcend sentimentality; they embody the deep knowledge that allows keepers to provide crucial information to veterinarians, ultimately enhancing accuracy of diagnosis and therapeutic results.

The Art of Anaesthetizing Big and Potentially Dangerous Animals

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinarians’ most critical responsibilities. Unlike standard operations at traditional veterinary clinics, anaesthetising a lion, rhino, or king cobra demands meticulous planning, specialised apparatus, and unwavering composure. The stakes are extraordinarily high: miscalculate the dosage for a two-tonne rhino and the animal’s cardiovascular system may collapse; give insufficient medication to a venomous snake and the keeper faces genuine mortal danger. ZSL’s veterinarians have spent decades developing procedures that take into account each animal’s unique physiology, physical structure, and metabolic peculiarities.

The procedure commences well ahead of the syringe penetrates flesh. Veterinarians study the specific creature’s medical history, consult with international specialists, and establish baseline vital signs. They arrange themselves with precision, ensuring quick availability to critical apparatus in case problems develop. Once the sedative begins working, continuous monitoring becomes paramount. Pulse, arterial tension, oxygen saturation, and body temperature are tracked relentlessly. Recovery periods demand comparably careful observation, as animals coming out of anaesthesia can behave unpredictably—as Guardian photographer David Levene found when King Arthur the cobra rose up and spat directly at him, despite the protective glass barrier.

Educating the Upcoming Generation of Zoo Veterinarians

The expertise required to treat threatened animals at ZSL does not develop overnight. Prospective zoo veterinarians undergo extended periods of rigorous training, beginning with standard veterinary qualifications before specialising in exotic and wild animal medicine. ZSL’s well-regarded reputation attracts accomplished professionals from throughout the globe, many of whom complete supervised placements under the organisation’s seasoned team. This hands-on education demonstrates as invaluable; theoretical learning alone cannot equip a vet for the uncertainty of sedating a lion or identifying illness in a at-risk species where each animal matters profoundly to conservation efforts.

The veterinary team at ZSL actively contributes in professional development within the zoo sector, sharing their accumulated knowledge through peer-reviewed articles, industry conferences, and joint research initiatives. Young veterinarians gain valuable experience through exposure to diverse cases—from routine health checks to urgent clinical procedures—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 sustained species preservation objectives and advancing scientific understanding of species preservation.

• Training with experienced ZSL veterinarians specialising in exotic animal care and urgent intervention
• Access to advanced diagnostic equipment and laboratory facilities for hands-on learning
• Engagement in international research collaborations advancing zoo veterinary medicine standards
• Exposure to diverse species needing species-specific medical strategies and treatment approaches centred on conservation