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 extraordinary challenges of treating some of the world’s rarest and most vulnerable animals. From sedating a king cobra that reacted to sedation with a toxic discharge to examining an Asiatic lion’s distinctly constricted ear canal, the vets, nurses and specialists working across ZSL’s facilities in London and Whipsnade navigate critical situations that most other medical practitioners 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 rare breed of medical expertise—one that has established standards in animal care for 200 years.

A Year of Unprecedented Medical Challenges

David Levene’s year-long photo documentation revealed the unpredictable nature of zoo animal medicine. On his second visit, the photographer encountered Bhanu, an Asiatic lion afflicted with chronic recurrent ear infections that had resulted in an exceptionally constricted ear canal. The condition required a general anaesthetic—always a last resort in zoo medicine—so the animal care specialists could conduct a thorough examination. Whilst Bhanu was under sedation, the vets took the chance to carry out comprehensive health checks, including careful examination of his teeth, which are essential for a meat-eater’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, 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 be fatal 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 requires sedation for aural examination
• Veterinary team performs multiple health checks during anaesthesia
• Zoo medicine calls for expertise with exotic and hazardous species

The Experts Responsible for Keeping Threatened Wildlife In Existence

The veterinary team at ZSL represents one of Britain’s most highly specialised workforces. With five fully trained veterinarians, six nursing staff, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity maintains what few UK zoos can match: a comprehensive, in-house medical facility. This integrated approach allows the team to address the intricate health demands of creatures spanning from dormice to rhinoceroses. Each specialist brings essential knowledge, whether identifying unusual parasitic infections, studying genetic material or conducting complex surgical procedures on animals worth millions to global conservation efforts.

The difficulties these professionals face are genuinely uncommon. Relocating a sedated rhino demands meticulous preparation and advanced apparatus. Sedating a dormouse requires exact pharmaceutical measurement for an animal weighing mere grams. Providing treatment to a venomous snake demands comprehending its behavioral patterns and physical makeup in ways that relatively few veterinarians ever encounter. The ZSL unit has to regularly adapt their methods, drawing on decades of accumulated knowledge whilst modifying their approaches to individual animals. Their work transcends routine check-ups; they are stewards of some of the planet’s most endangered species, where a single animal’s survival can carry major preservation implications.

From Original Founders to Contemporary Medical Practice

ZSL’s dedication to animal welfare stretches back two centuries. The journals of Charles Spooner, the zoo’s first “medical attendant,” offer some of the earliest written accounts of veterinary care in Britain. Spooner treated a young lion cub named Nelson suffering from mange infection, dental issues and a serious ulcer on his lower jaw. Through careful treatment—draining the ulcer and administering daily zinc sulphate solutions—Spooner saved the cub’s life, establishing a legacy of innovative and compassionate animal medicine that remains in place today.

This historical foundation has influenced modern ZSL veterinary practice. The principles Spooner pioneered—meticulous observation, 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 implemented worldwide. As the zoo celebrates its bicentenary, its veterinary team stands as a enduring monument to two hundred years of pioneering excellence in exotic animal medicine.

Surgical Precision on the World’s Most Endangered Creatures

Every surgical operation performed at ZSL represents a calculated risk with potentially enormous consequences. When a veterinarian operates on an endangered animal, they are not simply treating an individual patient—they are safeguarding a species whose continued existence could rely on that single life. The team must weigh the need to act with the inherent dangers of anaesthesia, infection and operative setbacks. Each decision is informed by decades of accumulated knowledge, collaborative research with international colleagues, and an intimate understanding of the specific animal’s medical history and individual quirks.

The difficulty increases substantially when working with creatures whose physical structure differs radically from tame species. A rhino’s cardiovascular system responds unpredictably to sedative drugs. A snake’s metabolic rate metabolises anaesthetic agents at rates that exceed conventional guidelines. A dormouse’s small frame leaves virtually no margin for error in drug dosing. The ZSL veterinary experts has established tailored approaches and observation technology to navigate these challenges, often developing novel methods that eventually become standard practice across zoological institutions worldwide.

• Anaesthetising dormice requires exact micrograms of carefully calculated 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 vital signs of overall health status.
• Post-operative monitoring involves 24-hour watchful care by dedicated veterinary nursing staff.

The Deep Bond Between Animal Carers and Creatures

Behind every successful medical intervention lies a profound relationship between caregiver 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 put under anaesthetic for his ear check, Humphrey seized the rare opportunity for tactile contact, cuddling the impressive animal whilst he lay unconscious. These connections go beyond mere emotion; they embody the thorough understanding that allows keepers to provide crucial information to veterinarians, ultimately enhancing diagnostic accuracy and treatment outcomes.

The Art of Anaesthetizing Big and Potentially Dangerous Creatures

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 meticulous planning, specialised apparatus, and unwavering composure. The stakes are exceptionally significant: get the dose wrong for a two-tonne rhino and the animal’s cardiovascular system may collapse; administer too little to a venomous snake and the keeper faces genuine mortal danger. ZSL’s veterinarians have spent decades refining protocols that account for each species’ unique physiology, physical structure, and metabolic characteristics.

The procedure begins long before the syringe enters flesh. Veterinarians study the specific creature’s medical history, consult with overseas experts, and establish baseline vital signs. They position themselves strategically, ensuring quick availability to emergency equipment should complications arise. Once the sedative begins working, continuous monitoring grows essential. Heart rate, blood pressure, blood oxygen levels, and body temperature are monitored intensively. Recovery periods require comparably careful observation, as animals coming out of anaesthesia can behave unpredictably—as Guardian photographer David Levene found when King Arthur the cobra reared up and spat straight towards him, despite the protective glass barrier.

Training the Future of Zoo Veterinarians

The specialised knowledge needed to care for threatened animals at ZSL does not emerge overnight. Prospective zoo veterinarians undergo extended periods of intensive training, starting with traditional veterinary qualifications before specialising in wild and exotic animal medicine. ZSL’s established reputation draws accomplished professionals from across the globe, many of whom complete supervised placements under the charity’s experienced team. This hands-on education demonstrates as invaluable; textbook knowledge alone cannot equip a vet for the variability of anaesthetising a lion or identifying illness in a at-risk species where each animal matters greatly to wildlife conservation.

The veterinary team at ZSL plays a key role in professional development within the zoo sector, sharing their accumulated knowledge through publications, conferences, and collaborative research projects. Young veterinarians gain valuable experience through exposure to diverse cases—from standard wellness examinations to emergency interventions—whilst working with specialists in pathology, microbiology, and molecular diagnostics. This cross-functional setting fosters innovation in animal healthcare and ensures that junior veterinarians understand the wider implications of zoo medicine: balancing immediate creature wellbeing with long-term conservation goals and advancing scientific understanding of species preservation.

• Guidance from experienced ZSL veterinarians focusing on care of exotic animals and emergency response
• Exposure to state-of-the-art diagnostic tools and laboratory facilities for hands-on learning
• Involvement in collaborative research projects improving standards in zoo veterinary medicine
• Familiarity to diverse species requiring species-specific medical strategies and conservation-focused treatment strategies