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 captured a year spent shadowing the charity’s elite veterinary team, recording the remarkable difficulties of caring for some of the world’s rarest and most vulnerable animals. From anaesthetising a king cobra that reacted to sedation with a venomous spray 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 encounter. With just a small number of British zoos employing their own in-house veterinarians, ZSL’s five-strong veterinary team, nursing staff of six, a pathologist and several specialists constitute a unique form of veterinary knowledge—one that has established animal welfare practices for two centuries.

A Year of Unprecedented Clinical Pressures

David Levene’s extended photo documentation revealed the unpredictable nature of zoo veterinary work. On his second day, the photographer encountered Bhanu, an Asiatic lion afflicted with chronic recurrent ear infections that had left him with an exceptionally constricted ear canal. The condition necessitated a full anaesthetic—always a final option in zoo medicine—so the animal care specialists could conduct a thorough examination. Whilst Bhanu was under sedation, the vets took the chance to perform comprehensive health checks, encompassing detailed inspection of his teeth, which are absolutely crucial for a carnivore’s survival and wellbeing 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 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 extraordinarily dangerous patients with practiced care and unwavering professionalism.

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

The Experts Responsible for Keeping At-Risk Animals Thriving

The animal health team at ZSL exemplifies one of Britain’s most specialised medical workforces. With five fully qualified veterinarians, six nursing staff, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity runs what most British zoos can match: a full in-house medical facility. This multidisciplinary approach allows the team to address the intricate health demands of creatures extending from dormice to rhinoceroses. Each specialist provides essential knowledge, whether detecting rare parasitic infections, studying genetic material or executing sophisticated surgical procedures on animals worth millions to global conservation efforts.

The obstacles these professionals encounter are distinctly exceptional. Shifting a sedated rhino demands thorough planning and specialist equipment. Sedating a dormouse requires exact pharmaceutical measurement for an animal weighing mere grams. Treating a venomous snake necessitates comprehending its behavioral patterns and physical makeup in ways that relatively few veterinarians come across. The ZSL team has to regularly adapt their methods, drawing on years of accumulated knowledge whilst modifying their methods to specific creatures. Their work goes well past regular assessments; they are guardians of some of the planet’s most endangered species, where a lone animal’s survival can bear significant ecological implications.

From Original Founders to Contemporary Medicine

ZSL’s focus on the welfare of animals stretches back two centuries. The journals of Charles Spooner, the zoo’s first “medical attendant,” provide some of the earliest written evidence of veterinary medicine in Britain. Spooner managed a young cub named Nelson afflicted with mange, teething troubles and a potentially fatal ulcer on his lower jaw. Through meticulous care—lancing the ulcer and applying daily zinc sulphate solutions—Spooner preserved the cub’s life, creating a legacy of innovative and compassionate animal medicine that persists today.

This historical foundation has shaped modern ZSL veterinary practice. The principles Spooner pioneered—meticulous observation, 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 veterinary care and animal welfare, disseminating findings and establishing techniques now embraced internationally. As the zoo commemorates 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 Planet’s Rarest Creatures

Every surgical procedure undertaken at ZSL represents a carefully weighed hazard with potentially enormous 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, joint investigations with overseas specialists, and an intimate understanding of the individual’s clinical background and individual quirks.

The intricacy increases substantially when handling creatures whose anatomy differs radically from tame species. A rhino’s circulatory system behaves inconsistently to sedative drugs. A snake’s metabolic processes 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 bespoke methods and surveillance equipment to address these difficulties, often pioneering approaches that later become standard practice across zoological institutions worldwide.

• Anaesthetising dormice requires accurate micrograms of carefully calculated pharmaceutical solutions.
• King cobras demand secure containment protocols during recovery from sedation procedures.
• Rhino relocations necessitate specialist equipment and integrated multi-agency operations.
• Dental examinations on carnivores reveal crucial indicators of overall health status.
• Post-operative monitoring involves 24-hour watchful care by dedicated veterinary nursing staff.

The Affectionate Relationship Between Animal Carers and Animals

Behind every effective medical intervention lies a profound relationship between caregiver and animal. Zookeepers like Tara Humphrey devote extensive time observing their animals, recognising minor changes in behaviour 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 asleep. These bonds transcend sentimentality; they embody the thorough understanding that allows keepers to deliver vital details to veterinarians, ultimately enhancing diagnostic accuracy and therapeutic results.

The Practice of Anaesthetizing Big and Potentially Dangerous Creatures

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinary team’s most essential responsibilities. Unlike standard operations at conventional animal hospitals, sedating a lion, rhino, or king cobra demands meticulous planning, specialist equipment, and unwavering composure. The stakes are exceptionally significant: get the dose wrong for a 2-tonne rhinoceros and the animal’s heart and circulatory system may collapse; administer too little to a venomous snake and the keeper encounters real risk of death. ZSL’s veterinarians have devoted years developing procedures that take into account each species’ distinctive biological makeup, physical structure, and metabolic peculiarities.

The process begins well ahead of the syringe enters flesh. Veterinarians examine the individual animal’s medical history, liaise with overseas experts, and determine standard physiological measurements. They arrange themselves with precision, ensuring quick availability to critical apparatus in case problems develop. Once the anaesthetic takes effect, constant observation grows essential. Heart rate, arterial tension, blood oxygen levels, and core heat are monitored intensively. Recovery periods require comparably careful observation, as animals emerging from sedation can behave unpredictably—as Guardian photographer David Levene found when King Arthur the cobra reared up and spat straight towards him, in spite of the protective glass barrier.

Preparing the Next Generation of Zoo Veterinarians

The skills needed to care for endangered animals at ZSL doesn’t materialise overnight. Prospective zoo veterinarians undergo years of intensive training, beginning with traditional veterinary qualifications before focusing in exotic and wild animal medicine. ZSL’s well-regarded reputation attracts talented professionals from across the globe, many of whom complete apprenticeships and mentorships under the charity’s seasoned team. This hands-on education demonstrates as invaluable; academic study alone cannot prepare 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 professional development within the zoo sector, disseminating expertise through publications, conferences, and collaborative research projects. Young veterinarians benefit from 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 animal healthcare and ensures that junior veterinarians understand the broader context of zoo medicine: reconciling immediate animal welfare with long-term conservation goals and contributing to scientific understanding of species preservation.

• Training with seasoned ZSL veterinarians specialising in exotic animal care and urgent intervention
• Access to advanced diagnostic tools and pathology laboratories for hands-on learning
• Participation in cross-border research initiatives enhancing zoo veterinary medicine standards
• Experience to a wide range of species requiring species-specific medical strategies and conservation-oriented care approaches