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 specialist animal doctors, capturing the remarkable difficulties of caring for some of the world’s rarest and most vulnerable animals. From sedating 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 employed at ZSL’s facilities in London and Whipsnade navigate medical emergencies that most other medical practitioners ever encounter. With just a small number of British zoos having their own resident vets, ZSL’s team of five vets, nursing staff of six, a animal pathologist and multiple specialist experts constitute a unique form of veterinary knowledge—one that has established animal welfare practices for 200 years.

A Year of Exceptional Clinical Pressures

David Levene’s extended photo documentation revealed the unpredictability of zoo animal medicine. On his second visit, the photographer encountered Bhanu, an Asiatic lion suffering from persistent recurring ear infections that had resulted in an unusually narrow 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 seized the opportunity to carry out detailed health assessments, encompassing 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 jabbed in the tail,” Levene recalls with wry humour. One bite from the young snake could prove fatal to an elephant, yet the ZSL team handles such exceptionally perilous patients with practised precision and unwavering professionalism.

• King cobra reacts to anaesthetic with venom-spraying display
• Asiatic lion demands sedation for aural examination
• Veterinary team carries out several health assessments during anaesthesia
• Zoo medicine calls for expertise with exotic and hazardous species

Those Specialists Who Keep Threatened Wildlife In Existence

The animal health team at ZSL represents one of Britain’s most highly specialised workforces. With five fully trained veterinarians, six nursing professionals, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity runs what few UK zoos can match: a comprehensive on-site medical facility. This integrated approach enables the team to manage the complex health needs of creatures ranging from dormice to rhinoceroses. Each specialist contributes vital skills, whether diagnosing obscure parasitic infections, studying genetic material or performing intricate surgical procedures on animals worth millions to global conservation efforts.

The obstacles these professionals encounter are distinctly uncommon. Relocating a anaesthetised rhino requires careful planning and specialised tools. Sedating a dormouse calls for accurate medication levels for an animal tipping the scales at mere grams. Treating a venomous snake demands understanding its behaviour and physiology in ways that scarcely any veterinarians ever encounter. The ZSL group continually needs to develop new approaches, drawing on years of accumulated knowledge whilst modifying their approaches to each animal. Their work transcends regular assessments; they are guardians of some of the planet’s most endangered species, where a single animal’s survival can hold profound conservation implications.

From Original Founders to Present-day Medical Practice

ZSL’s commitment to the welfare of animals stretches back two centuries. The journals of Charles Spooner, the zoo’s original “medical attendant,” give among the earliest documented records of veterinary medicine in Britain. Spooner cared for a lion cub named Nelson suffering from mange infection, dental issues and a potentially fatal ulcer on his jaw. Through careful intervention—draining the ulcer and giving daily zinc sulphate solutions—Spooner preserved the cub’s life, setting a record of compassionate and innovative veterinary care that remains in place today.

This longstanding foundation has informed modern ZSL veterinary practice. The principles Spooner pioneered—precise scrutiny, creative problem-solving and steadfast commitment to individual animals—remain fundamental to the team’s approach. Over two centuries, ZSL vets have consistently pushed boundaries in animal wellbeing and health, disseminating findings and establishing techniques now embraced internationally. As the zoo celebrates its bicentenary, its veterinary team stands as a lasting tribute to two hundred years of groundbreaking achievement in exotic animal medicine.

Precision Surgery on the Planet’s Rarest Species

Every surgical procedure undertaken at ZSL represents a carefully weighed hazard with far-reaching significant consequences. When a veterinarian operates on an species at risk, they are not simply caring for a single creature—they are protecting an entire population whose survival may depend on that one individual. The team must weigh the need to act with the inherent dangers of anaesthesia, infection and operative setbacks. Each choice draws upon by decades of accumulated knowledge, joint investigations with overseas specialists, and an deep knowledge of the specific animal’s medical history and individual quirks.

The complexity grows significantly when working with creatures whose physical structure differs radically from domestic livestock. A rhino’s circulatory system reacts unpredictably to anaesthetic administration. A snake’s metabolic processes processes anaesthetic agents at rates that defy standard protocols. A dormouse’s small frame leaves almost no room for error in pharmaceutical administration. The ZSL veterinary team has developed specialised techniques and surveillance equipment to address these difficulties, often pioneering approaches that subsequently become common procedure across zoo facilities worldwide.

• Anaesthetising dormice requires accurate 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 key markers of comprehensive health condition.
• Post-operative monitoring involves round-the-clock observation by specialist animal care staff.

The Emotional Connection Between Animal Carers and Creatures

Behind every effective medical procedure lies a profound relationship between keeper and creature. Zookeepers like Tara Humphrey devote extensive time observing their animals, recognising subtle behavioural shifts that signal illness or distress. When Bhanu the Asiatic lion was anaesthetised for his ear examination, Humphrey took the uncommon chance for physical affection, cuddling the magnificent beast whilst he lay asleep. These connections transcend sentimentality; they represent the deep knowledge that enables keepers to provide crucial information to veterinarians, ultimately enhancing accuracy of diagnosis and therapeutic results.

The Art of Anaesthetising Large and Hazardous Animals

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinary team’s most essential duties. Unlike routine procedures at conventional animal hospitals, sedating a lion, rhino, or king cobra demands meticulous planning, specialist equipment, and nerves of steel. The stakes are exceptionally significant: 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 take into account each species’ distinctive biological makeup, body composition, and metabolic peculiarities.

The procedure begins long before the syringe enters flesh. Veterinarians study the individual animal’s medical history, liaise with overseas experts, and determine standard physiological measurements. They arrange themselves with precision, ensuring rapid access to critical apparatus in case problems develop. Once the anaesthetic takes effect, continuous monitoring becomes paramount. Heart rate, arterial tension, blood oxygen levels, and core heat are monitored intensively. Post-operative phases demand comparably careful observation, as animals coming out of anaesthesia can behave unpredictably—as Guardian photographer David Levene discovered when King Arthur the cobra reared up and spat straight towards him, despite the protective glass barrier.

Educating the Next Generation of Zoo Veterinarians

The specialised knowledge needed to care for endangered animals at ZSL does not emerge overnight. Aspiring zoo veterinarians complete years of demanding training, beginning with traditional veterinary qualifications before specialising in exotic and wild animal medicine. ZSL’s established reputation attracts talented professionals from across 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 uncertainty of sedating a lion or identifying illness in a at-risk species where each animal matters significantly to conservation efforts.

The veterinary team at ZSL plays a key role in professional development within the zoo sector, sharing their accumulated knowledge through peer-reviewed articles, industry conferences, and joint research initiatives. Young veterinarians benefit from exposure to diverse cases—from routine health checks to urgent clinical procedures—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 sustained species preservation objectives and contributing to scientific understanding of species preservation.

• Training under experienced ZSL veterinarians with expertise in exotic animal care and emergency response
• Exposure to advanced diagnostic tools and laboratory facilities for practical training
• Engagement in collaborative research projects advancing zoo veterinary medicine standards
• Experience to various animal species needing species-specific medical strategies and conservation-oriented care approaches