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 documented a year spent shadowing the charity’s elite veterinary team, recording the remarkable difficulties of treating 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 employed at ZSL’s London and Whipsnade zoos manage medical emergencies that few other professionals 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 animal pathologist and multiple specialist experts constitute a rare breed of medical expertise—one that has pioneered standards in animal care for 200 years.

A Year of Unprecedented Medical Challenges

David Levene’s year-long photo documentation uncovered the unpredictability of zoo veterinary work. On his second visit, the photographer encountered Bhanu, an Asiatic lion suffering from persistent recurring ear infections that had left him with an unusually narrow ear canal. The condition required a general anaesthetic—always a final option in zoo medicine—so the veterinary team could conduct a thorough examination. Whilst Bhanu was under sedation, the vets took the chance to carry out detailed health assessments, including detailed inspection of his teeth, which are essential for a meat-eater’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 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 jabbed in the tail,” Levene recalls with wry humour. One bite from the young snake could cause death to an elephant, yet the ZSL team handles such exceptionally perilous patients with practiced care and unwavering professionalism.

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

Those Specialists Responsible for Keeping Threatened Wildlife Thriving

The veterinary team at ZSL represents one of Britain’s most specialist medical workforces. With five certified veterinarians, six nursing staff, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity runs what few British zoos can match: a full in-house medical facility. This multidisciplinary approach allows the team to address the intricate health demands of creatures ranging from dormice to rhinoceroses. Each specialist brings crucial expertise, whether detecting rare parasitic infections, studying genetic material or performing intricate surgical procedures on animals worth millions to global conservation efforts.

The difficulties these professionals face are genuinely uncommon. Shifting a anaesthetised rhino necessitates careful planning and advanced apparatus. Sedating a dormouse demands exact pharmaceutical measurement for an animal tipping the scales at mere grams. Managing the care of a venomous snake necessitates grasping its behavioral patterns and physical makeup in ways that relatively few veterinarians ever encounter. The ZSL team continually needs to innovate, drawing on years of accumulated knowledge whilst adapting their approaches to each animal. Their work goes well past routine check-ups; they are guardians of some of the Earth’s endangered species, where a single animal’s survival can hold major preservation implications.

From Original Innovators to Contemporary Healthcare

ZSL’s dedication to the welfare of animals extends back two centuries. The journals of Charles Spooner, the zoo’s first “medical attendant,” provide some of the first written accounts of veterinary care in Britain. Spooner treated a lion cub named Nelson suffering from mange infection, teething problems and a serious ulcer on his lower jaw. Through meticulous care—draining the ulcer and giving regular zinc sulphate treatments—Spooner saved the cub’s life, creating a record of compassionate and innovative veterinary care that persists today.

This historical foundation has informed modern ZSL veterinary practice. The principles Spooner pioneered—careful examination, resourceful approaches and unwavering dedication to individual animals—remain fundamental to the team’s approach. Over two centuries, ZSL vets have consistently pushed boundaries in animal health and welfare, disseminating findings and establishing techniques now implemented worldwide. 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 World’s Most Endangered Species

Every surgical operation performed at ZSL represents a calculated risk with far-reaching significant consequences. When a veterinarian operates on an endangered animal, they are not simply treating an individual patient—they are safeguarding a species whose survival may depend on that one individual. The team must weigh the need to act with the inherent dangers of anaesthesia, infection and surgical complications. Each decision is informed by years of gathered knowledge, joint investigations with overseas specialists, and an deep knowledge of the specific animal’s medical history and individual quirks.

The complexity increases substantially when working with creatures whose anatomy deviates substantially from tame species. A rhino’s cardiovascular system behaves inconsistently to anaesthetic administration. A snake’s metabolic processes processes anaesthetic agents at rates that defy standard protocols. A dormouse’s diminutive physique leaves almost no room for error in medication dosage. The ZSL veterinary staff has established tailored approaches and monitoring systems to overcome these obstacles, often developing novel methods that eventually become common procedure across zoological organisations worldwide.

• Anaesthetising dormice requires accurate micrograms of carefully calculated pharmaceutical solutions.
• King cobras demand robust enclosure protocols during recuperation following sedation procedures.
• Rhino relocations necessitate specialised apparatus and integrated multi-agency operations.
• Dental examinations on carnivores reveal key markers of overall health status.
• Post-operative monitoring involves continuous surveillance by dedicated veterinary nursing staff.

The Deep Bond Between Keepers and Animals

Behind every effective medical intervention lies a deep relationship between keeper and creature. Zookeepers like Tara Humphrey spend countless hours observing their charges, recognising subtle behavioural shifts that signal illness or distress. When Bhanu the Asiatic lion was anaesthetised for his ear examination, Humphrey took the uncommon chance for tactile contact, cuddling the magnificent beast whilst he lay asleep. These connections go beyond mere emotion; they represent the deep knowledge that enables keepers to deliver vital details to veterinarians, ultimately improving accuracy of diagnosis and therapeutic results.

The Art of Anaesthetizing Massive and Dangerous Creatures

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinarians’ most critical responsibilities. Unlike standard operations at traditional veterinary clinics, sedating a lion, rhino, or king cobra demands careful preparation, specialist equipment, and unwavering composure. The stakes are exceptionally significant: miscalculate the dosage for a 2-tonne rhinoceros and the animal’s heart and circulatory system may fail; administer too little to a venomous snake and the keeper faces real risk of death. ZSL’s veterinarians have spent decades developing procedures that take into account each animal’s distinctive biological makeup, body composition, and metabolic peculiarities.

The procedure begins well ahead of the syringe penetrates flesh. Veterinarians study the individual animal’s clinical background, liaise with overseas experts, and determine baseline vital signs. They arrange themselves with precision, ensuring quick availability to critical apparatus in case problems develop. Once the anaesthetic takes effect, continuous monitoring grows essential. Pulse, blood pressure, oxygen saturation, and body temperature are monitored intensively. Recovery periods demand equally vigilant 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 care for threatened animals at ZSL doesn’t materialise overnight. Prospective zoo veterinarians undergo extended periods of rigorous training, beginning with conventional veterinary qualifications before focusing in wild and exotic animal medicine. ZSL’s established reputation attracts accomplished professionals from across the globe, many of whom complete supervised placements under the organisation’s seasoned team. This direct education demonstrates as invaluable; academic study alone cannot prepare a vet for the variability of anaesthetising a lion or diagnosing illness in a severely threatened species where every individual matters profoundly to conservation efforts.

The veterinary team at ZSL actively contributes in professional development within the zoo sector, disseminating expertise through peer-reviewed articles, industry conferences, and joint research initiatives. Young veterinarians benefit from exposure to diverse cases—from standard wellness examinations to urgent clinical procedures—whilst working with specialists in pathology, microbiology, and molecular diagnostics. This multidisciplinary environment fosters innovation in veterinary medicine and ensures that junior veterinarians understand the broader context of zoo medicine: reconciling immediate animal welfare with long-term conservation goals and contributing to scientific understanding of species preservation.

• Mentorship from experienced ZSL veterinarians focusing on exotic animal care and urgent intervention
• Exposure to cutting-edge diagnostic tools and laboratory facilities for applied training
• Engagement in international research collaborations advancing zoo veterinary medicine standards
• Familiarity to various animal species needing species-specific medical strategies and conservation-oriented care approaches