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 spent shadowing the charity’s specialist animal doctors, capturing the extraordinary challenges of treating some of the world’s most dangerous and endangered animals. From sedating a king cobra that responded to anaesthetic with a toxic discharge to examining an Asiatic lion’s unusually narrow ear canal, the vets, nurses and specialists working across 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 resident vets, ZSL’s team of five vets, nursing staff of six, a pathologist and multiple specialist experts represent a unique form of veterinary knowledge—one that has pioneered animal welfare practices for 200 years.

A Year of Unprecedented Healthcare Difficulties

David Levene’s year-long photo documentation revealed the unpredictable nature of zoo veterinary work. On his second day, the photographer encountered Bhanu, an Asiatic lion suffering from persistent recurring ear infections that had left him with an unusually narrow ear canal. The condition necessitated a full anaesthetic—always a last resort in zoo medicine—so the animal care specialists could conduct a comprehensive assessment. Whilst Bhanu was under sedation, the vets seized the opportunity to carry out detailed health assessments, including detailed inspection of his teeth, which are absolutely crucial 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, received 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 responds to anaesthetic with venomous spitting display
• Asiatic lion needs sedation for aural examination
• Veterinary team carries out multiple health checks during anaesthesia
• Zoo medicine requires expertise with rare and dangerous species

The Experts Who Keep At-Risk Animals Alive

The veterinary staff at ZSL represents 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 maintains what few UK zoos can provide: a comprehensive on-site medical facility. This multidisciplinary approach allows the team to tackle the intricate health demands of creatures extending from dormice to rhinoceroses. Each specialist contributes crucial expertise, whether identifying unusual parasitic infections, examining genetic material or conducting complex surgical procedures on animals worth millions to global conservation efforts.

The difficulties these specialists deal with are distinctly uncommon. Moving a unconscious rhino requires careful planning and advanced apparatus. Anaesthetising a dormouse calls for precise dosing for an animal tipping the scales at mere grams. Providing treatment to a venomous snake requires grasping its behaviour and physiology in ways that relatively few veterinarians experience. The ZSL group must constantly develop new approaches, utilising extensive accumulated knowledge whilst modifying their techniques to specific creatures. Their work extends far beyond standard examinations; they are guardians of some of the world’s most endangered species, where a single animal’s survival can bear major preservation implications.

From Early Pioneers to Present-day Medical Practice

ZSL’s focus on animal wellbeing extends back two centuries. The journals of Charles Spooner, the zoo’s first “medical attendant,” provide among the earliest documented records of veterinary medicine in Britain. Spooner cared for a lion cub named Nelson affected by mange infection, teething troubles and a serious ulcer on his lower jaw. Through meticulous care—lancing the ulcer and applying daily doses of zinc sulphate—Spooner rescued the cub’s life, creating a record of compassionate and innovative veterinary care that persists today.

This historical foundation has informed modern ZSL veterinary practice. The principles Spooner pioneered—precise scrutiny, creative problem-solving and resolute devotion to individual animals—remain fundamental to the team’s approach. Over two centuries, ZSL vets have regularly extended boundaries in veterinary care and animal welfare, publishing research and developing techniques now embraced internationally. As the zoo commemorates its bicentenary, its veterinary team stands as a lasting tribute to two hundred years of groundbreaking achievement in exotic animal medicine.

Precise Surgical Intervention on the World’s Most Endangered Creatures

Every surgical operation performed at ZSL represents a carefully weighed hazard with far-reaching significant consequences. When a vet performs surgery 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 weigh the need to act with the inherent dangers of anaesthesia, infection and operative setbacks. Each decision is informed by years of gathered knowledge, collaborative research with international colleagues, and an intimate understanding of the individual’s clinical background and individual quirks.

The intricacy increases substantially when working with creatures whose anatomy differs radically from domesticated animals. A rhino’s circulatory system behaves inconsistently to sedation. A snake’s metabolic processes processes anaesthetic agents at rates that exceed conventional guidelines. A dormouse’s small frame leaves scarcely any allowance for error in medication dosage. The ZSL veterinary staff has created tailored approaches and observation technology to address these difficulties, often establishing innovative techniques that subsequently become common procedure across zoo facilities worldwide.

• Anaesthetising dormice requires exact micrograms of carefully calculated pharmaceutical solutions.
• King cobras demand robust enclosure protocols during recuperation following sedation procedures.
• Rhino relocations necessitate specialist equipment and coordinated multi-team operations.
• Dental examinations on carnivores reveal crucial indicators of general wellbeing.
• Post-operative monitoring involves round-the-clock observation by specialist animal care staff.

The Emotional Connection Between Animal Carers and Animals

Behind every effective medical procedure lies a deep relationship between keeper and creature. Zookeepers like Tara Humphrey spend countless hours observing their charges, identifying minor changes in behaviour that signal illness or discomfort. When Bhanu the Asian lion was put under anaesthetic for his ear check, Humphrey took the uncommon chance for physical affection, embracing the impressive animal whilst he lay unconscious. These bonds go beyond mere emotion; they represent the deep knowledge that enables keepers to provide crucial information to veterinarians, ultimately enhancing diagnostic accuracy and therapeutic results.

The Science 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 routine procedures at traditional veterinary clinics, anaesthetising a lion, rhino, or king cobra demands meticulous planning, specialised apparatus, and unwavering composure. The stakes are exceptionally significant: miscalculate the dosage for a two-tonne rhino and the animal’s cardiovascular system may collapse; administer too little to a venomous snake and the keeper encounters genuine mortal danger. ZSL’s veterinarians have devoted years developing procedures that account for each species’ unique physiology, body composition, and metabolic characteristics.

The process begins long before the syringe enters flesh. Veterinarians examine the individual animal’s medical history, consult with overseas experts, and determine baseline vital signs. They position themselves strategically, ensuring rapid access to critical apparatus should complications arise. Once the sedative begins working, constant observation grows essential. Heart rate, arterial tension, oxygen saturation, and core heat are monitored intensively. Recovery periods require equally vigilant observation, as animals emerging from sedation 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.

Educating the Next Generation of Zoo Veterinarians

The expertise needed to care for endangered animals at ZSL doesn’t materialise overnight. Aspiring zoo veterinarians undergo extended periods of intensive training, starting with standard veterinary qualifications before specialising in wild and exotic animal medicine. ZSL’s well-regarded reputation attracts accomplished professionals from throughout the globe, many of whom complete apprenticeships and mentorships under the organisation’s experienced team. This practical education proves to be invaluable; academic study alone cannot equip a vet for the uncertainty of sedating a lion or identifying illness in a severely threatened species where every individual matters profoundly 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 gain valuable experience through involvement with diverse cases—from routine health checks to emergency interventions—whilst working alongside specialists in pathology, microbiology, and molecular diagnostics. This cross-functional setting fosters innovation in veterinary medicine and ensures that emerging practitioners understand the broader context of zoo medicine: reconciling immediate creature wellbeing with sustained species preservation objectives and contributing to scientific understanding of species preservation.

• Mentorship with experienced ZSL veterinarians specialising in care of exotic animals and emergency response
• Exposure to state-of-the-art diagnostic equipment and pathology laboratories for practical training
• Involvement in collaborative research projects enhancing zoo veterinary medicine standards
• Experience to various animal species demanding species-specific medical strategies and treatment approaches centred on conservation