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 venomous spray to assessing an Asiatic lion’s unusually narrow ear canal, the vets, nurses and specialists employed at ZSL’s facilities in London and Whipsnade navigate critical situations that few other professionals ever encounter. With only a handful of British zoos employing their own resident vets, ZSL’s five-strong veterinary team, nursing staff of six, a pathologist and several specialists constitute a rare breed of medical expertise—one that has established animal welfare practices for 200 years.

A Year of Unprecedented Medical Challenges

David Levene’s extended photographic project revealed the unpredictable nature of zoo veterinary work. On his second visit, the documentarian found himself face-to-face with Bhanu, an Asiatic lion suffering from persistent recurring ear infections that had resulted in an exceptionally constricted ear canal. The condition necessitated a full anaesthetic—always a last resort in zoo medicine—so the veterinary team could conduct a thorough examination. Whilst Bhanu was under sedation, the vets seized the opportunity to perform comprehensive health checks, encompassing detailed inspection of his teeth, which are absolutely crucial for a carnivore’s wellbeing and survival in captivity.

Perhaps the most remarkable 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 injected in the tail,” Levene recalls with wry humour. One bite from the young snake could be fatal to an elephant, yet the ZSL team handles such extraordinarily dangerous patients with practiced care and unwavering professionalism.

• King cobra responds to anaesthetic with venomous spitting 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

Those Specialists Responsible for Keeping Threatened Wildlife Thriving

The veterinary staff at ZSL exemplifies one of Britain’s most specialist medical workforces. With five fully trained veterinarians, six veterinary nurses, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity operates what few UK zoos can match: a full in-house medical facility. This multidisciplinary approach allows the team to address the intricate health demands of creatures spanning from dormice to rhinoceroses. Each specialist contributes vital skills, whether identifying unusual parasitic infections, studying genetic material or conducting complex surgical procedures on animals worth millions to international conservation efforts.

The difficulties these professionals encounter are genuinely uncommon. Relocating a unconscious rhino requires thorough planning and advanced apparatus. Sedating a dormouse demands precise dosing for an animal weighing mere grams. Treating a venomous snake requires understanding its behaviour and physiology in ways that few veterinarians experience. The ZSL team continually needs to innovate, leveraging decades of accumulated knowledge whilst adjusting their techniques to each animal. Their work transcends standard examinations; they are custodians of some of the planet’s most endangered species, where a individual creature’s survival can carry profound conservation implications.

From Historic Innovators to Contemporary Healthcare

ZSL’s dedication to animal welfare extends back 200 years. The journals of Charles Spooner, the zoo’s first “medical attendant,” give some of the earliest written evidence of veterinary medicine in Britain. Spooner cared for a lion cub named Nelson afflicted with mange, dental issues and a potentially fatal ulcer on his lower jaw. Through careful intervention—draining the ulcer and applying daily doses of zinc sulphate—Spooner rescued the cub’s life, creating a tradition of innovative and compassionate animal medicine that remains in place today.

This longstanding foundation has shaped modern ZSL veterinary practice. The principles Spooner pioneered—careful examination, innovative solutions and resolute devotion to individual animals—remain central to the team’s approach. Over two centuries, ZSL vets have continually advanced boundaries in animal wellbeing and health, 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 pioneering excellence in exotic animal medicine.

Precise Surgical Intervention on the World’s Most Endangered Animals

Every surgical procedure undertaken at ZSL represents a calculated risk with potentially enormous consequences. When a veterinarian operates on an species at risk, they are not simply treating an individual patient—they are safeguarding a species whose continued existence could rely on that one individual. The team must balance the imperative to intervene with the inherent dangers of anaesthesia, infection and operative setbacks. Each decision is informed by years of gathered knowledge, collaborative research with overseas specialists, and an intimate understanding of the individual’s clinical background and unique characteristics.

The difficulty escalates dramatically when dealing with creatures whose bodily composition varies considerably from tame species. A rhino’s circulatory system behaves inconsistently to anaesthetic administration. A snake’s metabolic rate metabolises anaesthetic agents at rates that challenge established procedures. A dormouse’s diminutive physique leaves virtually no margin for error in medication dosage. The ZSL veterinary team has developed tailored approaches and observation technology to overcome these obstacles, often pioneering approaches that eventually become established protocol across zoological institutions worldwide.

• Anaesthetising dormice requires exact micrograms of meticulously formulated pharmaceutical solutions.
• King cobras demand safe housing protocols during recovery from sedation procedures.
• Rhino relocations necessitate specialised apparatus and integrated multi-agency operations.
• Dental examinations on carnivores reveal crucial indicators of comprehensive health condition.
• Post-operative monitoring involves round-the-clock observation by specialist animal care staff.

The Emotional Connection Between Keepers and Animals

Behind every successful medical intervention lies a profound relationship between keeper and creature. Zookeepers like Tara Humphrey spend countless hours observing their charges, identifying subtle behavioural shifts that signal illness or distress. When Bhanu the Asiatic lion was anaesthetised for his ear check, Humphrey took the uncommon chance for tactile contact, embracing the magnificent beast whilst he lay unconscious. These connections transcend sentimentality; they represent the deep knowledge that enables keepers to provide crucial information to veterinarians, ultimately enhancing diagnostic accuracy 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 duties. Unlike routine procedures at conventional animal hospitals, sedating a lion, rhino, or king cobra demands careful preparation, specialised apparatus, and nerves of steel. The stakes are exceptionally significant: miscalculate the dosage for a two-tonne rhino and the animal’s heart and circulatory system may fail; administer too little 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, body composition, and metabolic characteristics.

The process commences well ahead of the syringe penetrates flesh. Veterinarians study the individual animal’s clinical background, consult with international specialists, and determine baseline vital signs. They position themselves strategically, ensuring rapid access to emergency equipment should complications arise. Once the anaesthetic takes effect, constant observation becomes paramount. Heart rate, arterial tension, oxygen saturation, and core heat are monitored intensively. Recovery periods demand equally vigilant observation, as animals coming out of anaesthesia can behave unpredictably—as Guardian photographer David Levene discovered when King Arthur the cobra rose up and spat straight towards him, despite the protective glass barrier.

Preparing the Future of Zoo Veterinarians

The expertise required to treat threatened animals at ZSL does not emerge overnight. Aspiring zoo veterinarians complete extended periods of rigorous training, starting with traditional veterinary qualifications before specialising in exotic and wild animal medicine. ZSL’s established reputation attracts accomplished professionals from across the globe, many of whom complete mentored training under the organisation’s experienced team. This hands-on education proves to be invaluable; academic study alone cannot prepare a vet for the uncertainty of anaesthetising a lion or diagnosing illness in a at-risk species where each animal matters profoundly 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 exposure to diverse cases—from standard wellness examinations to emergency interventions—whilst working alongside specialists in pathology, microbiology, and molecular diagnostics. This cross-functional setting fosters innovation in animal healthcare and ensures that emerging practitioners understand the wider implications of zoo medicine: reconciling immediate creature wellbeing with long-term conservation goals and contributing to scientific understanding of species preservation.

• Training under expert ZSL veterinarians specialising in exotic animal care and urgent intervention
• Access to cutting-edge diagnostic tools and laboratory facilities for practical training
• Participation in collaborative research projects enhancing veterinary care standards for zoos
• Exposure to a wide range of species requiring tailored medical approaches and conservation-focused treatment strategies