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 most dangerous and endangered animals. From sedating a king cobra that responded to anaesthetic with a venomous spray to assessing an Asiatic lion’s unusually narrow ear canal, the vets, nurses and specialists employed at ZSL’s London and Whipsnade zoos navigate medical emergencies that most other medical practitioners ever face. With just a small number of British zoos having their own in-house veterinarians, ZSL’s team of five vets, nursing staff of six, a animal pathologist and several specialists constitute a rare breed of medical expertise—one that has pioneered standards in animal care for two centuries.

A Year of Exceptional Medical Challenges

David Levene’s year-long photo documentation revealed the unpredictable nature of zoo animal medicine. On his second day, the photographer 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 last resort in zoo medicine—so the veterinary team could conduct a thorough examination. Whilst Bhanu was sedated, the vets seized the opportunity to perform detailed health assessments, including detailed inspection of his teeth, which are essential for a meat-eater’s survival and wellbeing 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 responded 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 cause death to an elephant, yet the ZSL team handles such exceptionally perilous patients with practised precision and unwavering professionalism.

• King cobra reacts 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 Professionals Who Keep Threatened Wildlife Alive

The veterinary team at ZSL exemplifies one of Britain’s most highly specialised workforces. With five certified veterinarians, six veterinary nurses, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity operates what most British zoos can match: a full in-house medical facility. This multidisciplinary model enables the team to tackle the complex health needs of creatures extending from dormice to rhinoceroses. Each specialist contributes essential knowledge, whether diagnosing obscure parasitic infections, analysing genetic material or executing sophisticated surgical procedures on animals worth millions to global conservation efforts.

The difficulties these experts deal with are truly uncommon. Shifting a unconscious rhino necessitates careful planning and specialised tools. Anaesthetising a dormouse requires precise dosing for an animal weighing mere grams. Managing the care of a venomous snake demands comprehending its behaviour and physiology in ways that few veterinarians ever encounter. The ZSL unit must constantly adapt their methods, drawing on decades of accumulated knowledge whilst modifying their approaches to each animal. Their work extends far beyond routine check-ups; they are guardians of some of the planet’s most endangered species, where a individual creature’s survival can bear major preservation implications.

From Original Founders to Present-day Healthcare

ZSL’s dedication to 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 care in Britain. Spooner managed a young lion cub named Nelson suffering from mange infection, teething troubles and a potentially fatal ulcer on his jaw. Through careful treatment—lancing the ulcer and giving daily doses of zinc sulphate—Spooner rescued the cub’s life, founding a tradition of compassionate and innovative veterinary care that remains in place today.

This historical foundation has informed modern ZSL veterinary practice. The principles Spooner pioneered—precise scrutiny, resourceful approaches and unwavering dedication to individual animals—remain core 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 pioneering excellence in exotic animal medicine.

Surgical Precision 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 veterinarian operates 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 overseas specialists, and an deep knowledge of the specific animal’s medical history and unique characteristics.

The difficulty escalates dramatically when dealing with creatures whose bodily composition differs radically from domestic livestock. A rhino’s cardiovascular system responds unpredictably to anaesthetic administration. A snake’s metabolic rate breaks down anaesthetic agents at rates that challenge established procedures. A dormouse’s diminutive physique leaves scarcely any allowance for error in medication dosage. The ZSL veterinary team has created tailored approaches and surveillance equipment to navigate these challenges, often establishing innovative techniques that eventually become common procedure across zoological institutions worldwide.

• Anaesthetising dormice requires precise micrograms of meticulously formulated pharmaceutical solutions.
• King cobras demand safe housing protocols during recuperation following sedation procedures.
• Rhino relocations necessitate specialist equipment and collaborative multi-department operations.
• Dental examinations on carnivores reveal key markers of overall health status.
• Post-operative monitoring involves continuous surveillance by specialist animal care staff.

The Affectionate Relationship Between Keepers and Creatures

Behind every successful medical procedure lies a deep relationship between caregiver and creature. Zookeepers like Tara Humphrey spend countless hours observing their animals, identifying minor changes in behaviour that indicate illness or discomfort. When Bhanu the Asiatic lion was put under anaesthetic for his ear check, Humphrey seized the rare opportunity for physical affection, embracing the magnificent beast whilst he lay unconscious. These connections transcend sentimentality; they embody the deep knowledge that allows keepers to provide crucial information to veterinarians, ultimately enhancing diagnostic accuracy and treatment outcomes.

The Practice of Anaesthetising Massive and Dangerous Creatures

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinarians’ most critical duties. Unlike standard operations at conventional animal hospitals, sedating a lion, rhino, or king cobra demands careful preparation, specialist equipment, 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; administer too little to a venomous snake and the keeper faces 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 characteristics.

The procedure commences well ahead of the syringe enters flesh. Veterinarians study the individual animal’s clinical background, consult with international specialists, and establish baseline vital signs. They arrange themselves with precision, ensuring rapid access to emergency equipment should complications arise. Once the sedative begins working, constant observation becomes paramount. Pulse, arterial tension, oxygen saturation, and body temperature are tracked relentlessly. Recovery periods require comparably careful observation, as animals emerging from sedation can act erratically—as Guardian photographer David Levene discovered when King Arthur the cobra reared up and spat directly at him, in spite of the protective glass barrier.

Training the Next Generation of Zoo Veterinarians

The skills needed to care for endangered animals at ZSL does not develop overnight. Aspiring zoo veterinarians complete extended periods of demanding training, beginning with conventional veterinary qualifications before focusing in exotic and wild animal medicine. ZSL’s established reputation attracts skilled professionals from across the globe, many of whom complete apprenticeships and mentorships under the organisation’s seasoned team. This hands-on education demonstrates as invaluable; academic study alone cannot equip a vet for the uncertainty of anaesthetising a lion or diagnosing illness in a severely threatened species where every individual matters profoundly to wildlife conservation.

The veterinary team at ZSL actively contributes in career advancement within the zoo sector, sharing their accumulated knowledge through publications, conferences, and collaborative research projects. Young veterinarians benefit from involvement with diverse cases—from standard wellness examinations 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.

• Mentorship with seasoned ZSL veterinarians focusing on exotic animal care and emergency procedures
• Exposure to advanced diagnostic equipment and laboratory facilities for applied training
• Involvement in collaborative research projects improving veterinary care standards for zoos
• Familiarity to various animal species needing tailored medical approaches and conservation-oriented care approaches