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 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 reacted to sedation with a venomous spray to assessing an Asiatic lion’s distinctly constricted ear canal, the vets, nurses and specialists employed at ZSL’s facilities in London and Whipsnade manage medical emergencies that few other professionals ever encounter. With only a handful of British zoos employing their own in-house veterinarians, ZSL’s five-strong veterinary team, six nurses, a pathologist and several specialists represent a unique form of veterinary knowledge—one that has pioneered standards in animal care for two centuries.

A Year of Unprecedented Medical Challenges

David Levene’s extended photo documentation revealed the unpredictable nature of zoo veterinary work. On his second visit, the documentarian encountered Bhanu, an Asiatic lion suffering from chronic recurrent ear infections that had left him with an exceptionally constricted ear canal. The condition required 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 took the chance to perform 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 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 extraordinarily dangerous patients with practiced care and unwavering professionalism.

• King cobra reacts to anaesthetic with venomous spitting display
• Asiatic lion demands sedation for aural examination
• Veterinary team performs multiple health checks during anaesthesia
• Zoo medicine requires expertise with rare and dangerous species

The Professionals Who Keep Threatened Wildlife Alive

The veterinary team at ZSL constitutes one of Britain’s most specialised 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 most British zoos can provide: a comprehensive, in-house medical facility. This multidisciplinary approach allows the team to tackle the complex health needs of creatures ranging from dormice to rhinoceroses. Each specialist provides essential knowledge, whether detecting rare parasitic infections, analysing genetic material or conducting complex surgical procedures on animals worth millions to worldwide conservation efforts.

The challenges these experts encounter are distinctly exceptional. Moving a sedated rhino necessitates meticulous preparation and specialist equipment. Anaesthetising a dormouse calls for precise dosing for an animal weighing mere grams. Treating a venomous snake necessitates understanding its behavioral patterns and physical makeup in ways that few veterinarians experience. The ZSL team must constantly innovate, utilising extensive accumulated knowledge whilst adjusting their techniques to each animal. Their work goes well past routine check-ups; they are custodians of some of the Earth’s endangered species, where a lone animal’s survival can carry profound conservation implications.

From Original Pioneers to Modern Medical Practice

ZSL’s dedication to animal wellbeing extends back two centuries. The journals of Charles Spooner, the zoo’s original “medical attendant,” give some of the first written evidence of animal medical care in Britain. Spooner cared for a young lion cub named Nelson affected by mange, teething problems and a serious ulcer on his jaw. Through meticulous care—opening the ulcer and administering regular zinc sulphate treatments—Spooner rescued the cub’s life, establishing a record of compassionate and innovative veterinary care that persists today.

This enduring foundation has shaped modern ZSL veterinary practice. The principles Spooner pioneered—meticulous observation, creative problem-solving and unwavering dedication to individual animals—remain fundamental to the team’s approach. Over two centuries, ZSL vets have consistently pushed boundaries in veterinary care and animal welfare, publishing research and developing techniques now adopted globally. 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.

Surgical Precision on the Earth’s Rarest Animals

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 caring for a single creature—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 surgical complications. Each decision is informed by years of gathered knowledge, collaborative research with international colleagues, and an intimate understanding of the specific animal’s medical history and unique characteristics.

The complexity escalates dramatically when working with creatures whose bodily composition differs radically from domesticated animals. A rhino’s circulatory system responds unpredictably to sedative drugs. A snake’s metabolism metabolises anaesthetic agents at rates that challenge established procedures. A dormouse’s small frame leaves almost no room for error in medication dosage. The ZSL veterinary team has created tailored approaches and observation technology to navigate these challenges, often establishing innovative techniques that later become established protocol across zoological organisations 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 specialist equipment and integrated multi-agency operations.
• Dental examinations on carnivores reveal key markers of comprehensive health condition.
• Post-operative monitoring involves round-the-clock observation by experienced veterinary support staff.

The Affectionate Relationship Between Animal Carers and Creatures

Behind every effective medical intervention lies a deep relationship between keeper and animal. Zookeepers like Tara Humphrey spend countless hours observing their charges, recognising minor changes in behaviour that indicate illness or distress. When Bhanu the Asiatic lion was anaesthetised for his ear check, Humphrey took the uncommon chance for physical affection, cuddling the impressive animal whilst he lay asleep. These connections go beyond mere emotion; they represent the deep knowledge that enables keepers to provide crucial information to veterinarians, ultimately enhancing accuracy of diagnosis and treatment outcomes.

The Art of Anaesthetising Large and Hazardous Animals

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinarians’ most essential duties. Unlike routine procedures at conventional animal hospitals, anaesthetising a lion, rhino, or king cobra demands careful preparation, specialised apparatus, and nerves of steel. The stakes are extraordinarily high: get the dose wrong for a two-tonne rhino and the animal’s cardiovascular system may collapse; give insufficient medication to a venomous snake and the keeper faces real risk of death. ZSL’s veterinarians have spent decades refining protocols that account for each species’ distinctive biological makeup, physical structure, and metabolic characteristics.

The process begins well ahead of the syringe enters flesh. Veterinarians examine the specific creature’s clinical background, liaise with international specialists, and establish baseline vital signs. They position themselves strategically, ensuring quick availability to critical apparatus in case problems develop. Once the sedative begins working, continuous monitoring grows essential. Pulse, blood pressure, oxygen saturation, and core heat are tracked relentlessly. Post-operative phases demand equally vigilant observation, as animals emerging from sedation can act erratically—as Guardian photographer David Levene found when King Arthur the cobra reared up and spat directly at him, in spite of the protective glass barrier.

Preparing the Next Generation of Zoo Veterinarians

The expertise needed to treat endangered animals at ZSL does not develop overnight. Aspiring zoo veterinarians complete years of demanding training, starting with traditional veterinary qualifications before focusing in exotic and wild animal medicine. ZSL’s strong reputation attracts accomplished professionals from throughout the globe, many of whom complete mentored training under the organisation’s experienced team. This hands-on education proves invaluable; theoretical learning alone cannot prepare a vet for the variability of sedating a lion or identifying illness in a critically endangered species where every individual matters greatly to conservation work.

The veterinary team at ZSL actively contributes in professional development within the zoo sector, sharing their accumulated knowledge through publications, conferences, and collaborative research projects. Young veterinarians gain valuable experience through involvement with diverse cases—from standard wellness examinations to urgent clinical procedures—whilst working alongside specialists in pathology, microbiology, and molecular diagnostics. This multidisciplinary environment fosters innovation in animal healthcare and ensures that emerging practitioners understand the wider implications of zoo medicine: balancing immediate animal welfare with sustained species preservation objectives and contributing to scientific understanding of species preservation.

• Training from expert ZSL veterinarians specialising in care of exotic animals and emergency procedures
• Exposure to state-of-the-art diagnostic equipment and pathology laboratories for practical training
• Participation in international research collaborations advancing zoo veterinary medicine standards
• Exposure to diverse species demanding tailored medical approaches and conservation-focused treatment strategies