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 following the charity’s elite veterinary team, capturing the remarkable difficulties of caring for some of the world’s most dangerous and endangered animals. From sedating 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 London and Whipsnade zoos navigate medical emergencies that most other medical practitioners ever face. With just a small number of British zoos having their own resident vets, ZSL’s five-strong veterinary team, six nurses, a pathologist and several specialists represent a rare breed of medical expertise—one that has pioneered standards in animal care for two centuries.

A Year of Exceptional Clinical Pressures

David Levene’s extended photographic project revealed the unpredictable nature of zoo animal medicine. On his second visit, the photographer found himself face-to-face with Bhanu, an Asiatic lion suffering from persistent recurring ear infections that had left him with an unusually narrow ear canal. The condition required a full anaesthetic—always a final option in zoo medicine—so the veterinary team could perform a comprehensive assessment. Whilst Bhanu was sedated, the vets took the chance to carry out comprehensive health checks, including detailed inspection of his teeth, which are absolutely crucial for a carnivore’s survival and wellbeing in captivity.

Perhaps the most dramatic 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 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 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 exceptionally perilous patients with practiced care and unwavering professionalism.

• King cobra reacts to anaesthetic with venomous spitting display
• Asiatic lion demands sedation for ear canal examination
• Veterinary team performs several health assessments during anaesthesia
• Zoo medicine calls for expertise with exotic and hazardous species

The Experts That Maintain Endangered Species Alive

The animal health team at ZSL constitutes one of Britain’s most specialist medical workforces. With five certified veterinarians, six nursing professionals, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity runs what most British zoos can replicate: a comprehensive on-site medical facility. This multidisciplinary model allows the team to tackle the complicated medical requirements of creatures spanning from dormice to rhinoceroses. Each specialist contributes essential knowledge, whether identifying unusual parasitic infections, examining genetic material or executing sophisticated surgical procedures on animals worth millions to global conservation efforts.

The obstacles these professionals face are truly unique. Relocating a sedated rhino requires thorough planning and advanced apparatus. Sedating a dormouse requires precise dosing for an animal tipping the scales at mere grams. Managing the care of a venomous snake necessitates comprehending its behavioral patterns and physical makeup in ways that relatively few veterinarians experience. The ZSL group continually needs to develop new approaches, utilising extensive accumulated knowledge whilst adapting their methods to individual animals. Their work transcends routine check-ups; they are guardians of some of the Earth’s endangered species, where a lone animal’s survival can bear profound conservation implications.

From Original Founders to Modern Medicine

ZSL’s focus on animal wellbeing stretches back two centuries. The journals of Charles Spooner, the zoo’s first “medical attendant,” offer some of the first documented records of animal medical care in Britain. Spooner treated a lion cub named Nelson afflicted with mange infection, dental issues and a serious ulcer on his lower jaw. Through careful treatment—opening the ulcer and applying daily doses of zinc sulphate—Spooner rescued the cub’s life, setting a record of innovative, compassionate animal medicine that persists today.

This longstanding foundation has shaped modern ZSL veterinary practice. The principles Spooner pioneered—careful examination, resourceful approaches and steadfast commitment 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 marks its bicentenary, its veterinary team stands as a enduring monument to two hundred years of groundbreaking achievement in exotic animal medicine.

Precision Surgery on the Planet’s Rarest Creatures

Every surgical procedure undertaken 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 protecting an entire population whose survival may depend on that one individual. The team must weigh the need to act with the fundamental risks of anaesthesia, infection and surgical complications. Each decision is informed by decades of accumulated knowledge, collaborative research with overseas specialists, and an intimate understanding of the individual’s clinical background and individual quirks.

The complexity grows significantly when dealing with creatures whose anatomy deviates substantially from tame species. A rhino’s circulatory system reacts unpredictably to sedation. A snake’s metabolic rate processes anaesthetic agents at rates that defy standard protocols. A dormouse’s small frame leaves scarcely any allowance for error in drug dosing. The ZSL veterinary staff has developed tailored approaches and observation technology to overcome these obstacles, often pioneering approaches that subsequently become established protocol across zoological institutions worldwide.

• Anaesthetising dormice requires precise micrograms of carefully calculated pharmaceutical solutions.
• King cobras demand safe housing protocols during recuperation following sedation procedures.
• Rhino relocations necessitate specialised apparatus and collaborative multi-department operations.
• Dental examinations on carnivores reveal key markers of comprehensive health condition.
• Post-operative monitoring involves 24-hour watchful care by dedicated veterinary nursing staff.

The Deep Bond Between Keepers and Creatures

Behind every effective medical procedure lies a deep relationship between caregiver and creature. Zookeepers like Tara Humphrey spend countless hours observing their charges, identifying subtle behavioural shifts that indicate 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 embody the deep knowledge that allows keepers to deliver vital details to veterinarians, ultimately improving accuracy of diagnosis and treatment outcomes.

The Practice of Anaesthetising Big and Potentially Dangerous Wildlife

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinarians’ most essential responsibilities. Unlike standard operations at traditional veterinary clinics, anaesthetising a lion, rhino, or king cobra demands careful preparation, specialised apparatus, and nerves of steel. The stakes are exceptionally significant: get the dose wrong 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 real risk of death. ZSL’s veterinarians have spent decades developing procedures that account for each animal’s distinctive biological makeup, physical structure, and metabolic peculiarities.

The process commences long before the syringe penetrates flesh. Veterinarians study the individual animal’s clinical background, consult with overseas experts, and establish baseline vital signs. They arrange themselves with precision, ensuring quick availability to emergency equipment in case problems develop. Once the sedative begins working, continuous monitoring becomes paramount. Heart rate, blood pressure, oxygen saturation, and body temperature are tracked relentlessly. Post-operative phases 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 straight towards him, despite the protective glass barrier.

Preparing the Future of Zoo Veterinarians

The specialised knowledge required to care for endangered animals at ZSL doesn’t materialise overnight. Prospective zoo veterinarians complete years of intensive training, starting with standard veterinary qualifications before focusing in exotic and wild animal medicine. ZSL’s well-regarded reputation attracts accomplished professionals from across the globe, many of whom undertake apprenticeships and mentorships under the charity’s seasoned team. This hands-on education proves to be invaluable; textbook knowledge alone cannot equip a vet for the unpredictability of anaesthetising a lion or diagnosing illness in a at-risk species where every individual matters significantly to conservation work.

The veterinary team at ZSL plays a key role in career advancement within the zoo sector, sharing their accumulated knowledge through publications, conferences, and collaborative research projects. Young veterinarians benefit from exposure to diverse cases—from routine health checks to emergency interventions—whilst working alongside specialists in pathology, microbiology, and molecular diagnostics. This multidisciplinary environment fosters innovation in animal healthcare and ensures that junior veterinarians understand the wider implications of zoo medicine: reconciling immediate animal welfare with sustained species preservation objectives and contributing to scientific understanding of species preservation.

• Training with expert ZSL veterinarians specialising in care of exotic animals and urgent intervention
• Exposure to advanced diagnostic equipment and pathology laboratories for practical training
• Involvement in collaborative research projects improving veterinary care standards for zoos
• Familiarity to a wide range of species needing species-specific medical strategies and treatment approaches centred on conservation