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

As the Zoological Society of London celebrates its 200th anniversary this spring, Guardian photographer David Levene has documented a year following the charity’s elite veterinary team, capturing the remarkable difficulties of treating some of the world’s most dangerous and endangered animals. From anaesthetising a king cobra that responded to anaesthetic with a toxic discharge to assessing an Asiatic lion’s unusually narrow ear canal, the vets, nurses and specialists working across ZSL’s facilities in London and Whipsnade navigate 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, six nurses, a animal pathologist and several specialists constitute a rare breed of medical expertise—one that has pioneered standards in animal care for 200 years.

A Year of Exceptional Clinical Pressures

David Levene’s extended photo documentation uncovered the unpredictable nature of zoo animal medicine. On his second day, the photographer encountered Bhanu, an Asiatic lion afflicted with chronic recurrent ear infections that had resulted in an exceptionally constricted ear canal. The condition necessitated a full anaesthetic—always a final option in zoo medicine—so the veterinary team could conduct a comprehensive assessment. Whilst Bhanu was under sedation, the vets seized the opportunity to carry out comprehensive health checks, including careful examination of his teeth, which are absolutely crucial for a carnivore’s wellbeing and survival 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 jabbed 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 displays anaesthetic with venom-spraying display
• Asiatic lion requires 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 At-Risk Animals Thriving

The veterinary staff at ZSL constitutes one of Britain’s most highly specialised workforces. With five certified veterinarians, six nursing staff, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity operates what most British zoos can provide: a full in-house medical facility. This multidisciplinary model permits the team to tackle the complex health needs of creatures ranging from dormice to rhinoceroses. Each specialist brings essential knowledge, whether detecting rare parasitic infections, examining genetic material or performing intricate surgical procedures on animals worth millions to worldwide conservation efforts.

The challenges these experts deal with are truly exceptional. Relocating a anaesthetised rhino demands thorough planning and specialist equipment. Sedating a dormouse requires precise dosing for an animal weighing mere grams. Treating a venomous snake requires grasping its behavioral patterns and physical makeup in ways that few veterinarians ever encounter. The ZSL team continually needs to develop new approaches, leveraging years of accumulated knowledge whilst adjusting their approaches to each animal. Their work extends far beyond routine check-ups; they are custodians of some of the planet’s most endangered species, where a individual creature’s survival can carry significant ecological implications.

From Original Innovators to Modern Healthcare

ZSL’s focus on animal wellbeing stretches back two centuries. The journals of Charles Spooner, the zoo’s original “medical attendant,” offer among the earliest written accounts of veterinary care in Britain. Spooner managed a young cub named Nelson suffering from mange infection, teething troubles and a potentially fatal ulcer on his lower jaw. Through meticulous care—lancing the ulcer and administering daily zinc sulphate solutions—Spooner rescued the cub’s life, establishing a legacy of compassionate and innovative veterinary care that continues today.

This historical foundation has influenced modern ZSL veterinary practice. The principles Spooner pioneered—careful examination, innovative solutions and resolute devotion to individual animals—remain core to the team’s approach. Over two centuries, ZSL vets have continually advanced boundaries in veterinary care and animal welfare, producing research and creating techniques now adopted globally. As the zoo marks its bicentenary, its veterinary team stands as a enduring monument to two hundred years of innovative leadership in exotic animal medicine.

Precision Surgery on the Earth’s Rarest Species

Every surgical procedure undertaken at ZSL represents a calculated risk with potentially enormous consequences. When a vet performs surgery on an species at risk, they are not simply treating an individual patient—they are protecting an entire population whose continued existence could rely 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, joint investigations with international colleagues, and an intimate understanding of the individual’s clinical background and unique characteristics.

The difficulty escalates dramatically when handling creatures whose anatomy deviates substantially from domestic livestock. A rhino’s cardiovascular system reacts unpredictably to sedative drugs. A snake’s metabolic processes breaks down 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 experts has developed bespoke methods and observation technology to navigate these challenges, often developing novel methods that subsequently become standard practice across zoological organisations worldwide.

• Anaesthetising dormice requires precise micrograms of carefully calculated pharmaceutical solutions.
• King cobras demand robust enclosure protocols during recuperation following sedation procedures.
• Rhino relocations necessitate expert-level gear and coordinated multi-team operations.
• Dental examinations on carnivores reveal crucial indicators of general wellbeing.
• Post-operative monitoring involves 24-hour watchful care by experienced veterinary support staff.

The Emotional Connection Between Animal Carers and Animals

Behind every effective medical procedure lies a deep relationship between keeper and animal. Zookeepers like Tara Humphrey spend countless hours observing their animals, recognising subtle behavioural shifts that indicate illness or distress. When Bhanu the Asian lion was anaesthetised for his ear check, Humphrey seized the rare opportunity for physical affection, embracing the impressive animal whilst he lay asleep. These connections transcend sentimentality; they embody the deep knowledge that enables keepers to provide crucial information to veterinarians, ultimately improving accuracy of diagnosis and treatment outcomes.

The Art of Anaesthetising Big and Potentially Dangerous Creatures

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinarians’ most essential duties. Unlike standard operations at conventional animal hospitals, anaesthetising a lion, rhino, or king cobra demands meticulous planning, specialist equipment, and unwavering composure. The stakes are extraordinarily high: get the dose wrong 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 encounters real risk of death. ZSL’s veterinarians have devoted years refining protocols that take into account each species’ distinctive biological makeup, body composition, and metabolic peculiarities.

The procedure begins well ahead of the syringe penetrates flesh. Veterinarians examine the individual animal’s clinical background, consult with international specialists, and establish standard physiological measurements. They arrange themselves with precision, ensuring rapid access to emergency equipment should complications arise. Once the sedative begins working, constant observation grows essential. Pulse, blood pressure, oxygen saturation, and core heat are monitored intensively. Recovery periods require comparably careful observation, as animals coming out of anaesthesia can act erratically—as Guardian photographer David Levene discovered when King Arthur the cobra reared up and spat straight towards him, in spite of the protective glass barrier.

Training the Next Generation of Zoo Veterinarians

The skills required to treat threatened animals at ZSL doesn’t materialise overnight. Prospective zoo veterinarians undergo years of intensive training, beginning with conventional veterinary qualifications before specialising in exotic and wild animal medicine. ZSL’s strong reputation attracts talented professionals from throughout the globe, many of whom complete supervised placements under the charity’s seasoned team. This direct education demonstrates as invaluable; textbook knowledge alone cannot equip a vet for the unpredictability of anaesthetising a lion or identifying illness in a at-risk species where every individual matters profoundly to conservation efforts.

The veterinary team at ZSL plays a key role in career advancement within the zoo sector, disseminating expertise 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 emerging practitioners understand the wider implications of zoo medicine: reconciling immediate animal welfare with sustained species preservation objectives and advancing scientific understanding of species preservation.

• Mentorship under experienced ZSL veterinarians focusing on exotic animal care and emergency procedures
• Access to state-of-the-art diagnostic equipment and pathology laboratories for hands-on learning
• Participation in international research collaborations advancing zoo veterinary medicine standards
• Exposure to a wide range of species requiring tailored medical approaches and treatment approaches centred on conservation