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 remarkable difficulties of treating some of the world’s rarest and most vulnerable animals. From sedating a king cobra that responded to anaesthetic with a venomous spray to assessing an Asiatic lion’s distinctly constricted ear canal, the vets, nurses and specialists working across ZSL’s London and Whipsnade zoos manage medical emergencies that few other professionals ever face. With only a handful of British zoos employing their own in-house veterinarians, ZSL’s five-strong veterinary team, nursing staff of six, a pathologist and multiple specialist experts constitute a unique form of veterinary knowledge—one that has established standards in animal care for two centuries.

A Year of Exceptional Clinical Pressures

David Levene’s year-long photographic project revealed the unpredictable nature of zoo veterinary work. On his second visit, the photographer encountered Bhanu, an Asiatic lion afflicted with persistent recurring ear infections that had resulted in an unusually narrow ear canal. The condition necessitated a general anaesthetic—always a last resort in zoo medicine—so the veterinary team could conduct a thorough examination. Whilst Bhanu was under sedation, the vets seized the opportunity to perform comprehensive health checks, encompassing careful examination of his teeth, which are absolutely crucial for a meat-eater’s survival and wellbeing in captivity.

Perhaps the most striking 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 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 practiced care and unwavering professionalism.

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

Those Specialists Responsible for Keeping Threatened Wildlife Alive

The veterinary staff at ZSL constitutes one of Britain’s most specialist medical workforces. With five fully qualified veterinarians, six nursing staff, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity operates what few British zoos can match: a comprehensive on-site medical facility. This multidisciplinary model enables the team to tackle the complicated medical requirements of creatures spanning from dormice to rhinoceroses. Each specialist provides vital skills, whether identifying unusual parasitic infections, examining genetic material or conducting complex surgical procedures on animals worth millions to worldwide conservation efforts.

The obstacles these professionals deal with are distinctly unique. Relocating a unconscious rhino demands thorough planning and specialised tools. Sedating a dormouse demands exact pharmaceutical measurement for an animal weighing mere grams. Providing treatment to a venomous snake demands grasping its behavioral patterns and physical makeup in ways that relatively few veterinarians come across. The ZSL team must constantly innovate, leveraging decades of accumulated knowledge whilst modifying their methods to each animal. Their work extends far beyond standard examinations; they are custodians of some of the planet’s most endangered species, where a single animal’s survival can carry major preservation implications.

From Historic Innovators to Modern Medical Practice

ZSL’s commitment to the welfare of animals stretches back two centuries. The journals of Charles Spooner, the zoo’s first “medical attendant,” provide some of the first documented records of animal medical care in Britain. Spooner managed a young cub named Nelson affected by mange, teething troubles and a serious ulcer on his jaw. Through careful intervention—opening the ulcer and applying daily zinc sulphate solutions—Spooner preserved the cub’s life, setting a record of innovative, compassionate animal medicine that continues today.

This historical foundation has influenced 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 continually advanced boundaries in animal health and welfare, publishing research and developing techniques now embraced internationally. As the zoo celebrates its bicentenary, its veterinary team stands as a enduring monument to two hundred years of pioneering excellence in exotic animal medicine.

Precise Surgical Intervention on the Planet’s Rarest Species

Every surgical procedure undertaken at ZSL represents a calculated risk 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 safeguarding a species whose continued existence could rely on that single life. The team must balance the imperative to intervene with the inherent dangers of anaesthesia, infection and operative setbacks. Each choice draws upon by years of gathered knowledge, joint investigations with international colleagues, and an deep knowledge of the specific animal’s medical history and unique characteristics.

The intricacy increases substantially when dealing with creatures whose anatomy deviates substantially from domestic livestock. A rhino’s circulatory system responds unpredictably to sedation. A snake’s metabolic processes breaks down anaesthetic agents at rates that exceed conventional guidelines. A dormouse’s small frame leaves scarcely any allowance for error in pharmaceutical administration. The ZSL veterinary staff has created bespoke methods and monitoring systems to overcome these obstacles, often developing novel methods that eventually become standard practice across zoological organisations worldwide.

• Anaesthetising dormice requires accurate micrograms of meticulously formulated pharmaceutical solutions.
• King cobras demand robust enclosure protocols during recuperation following sedation procedures.
• Rhino relocations necessitate expert-level gear and integrated multi-agency operations.
• Dental examinations on carnivores reveal vital signs of comprehensive health condition.
• Post-operative monitoring involves round-the-clock observation by dedicated veterinary nursing staff.

The Affectionate Relationship Between Keepers and Creatures

Behind every successful medical procedure lies a deep relationship between keeper and animal. Zookeepers like Tara Humphrey spend countless hours observing their animals, identifying subtle behavioural shifts that signal illness or discomfort. When Bhanu the Asian lion was anaesthetised for his ear examination, Humphrey took the uncommon chance for tactile contact, embracing the impressive animal whilst he lay asleep. These connections go beyond mere emotion; they represent the deep knowledge that allows keepers to deliver vital details to veterinarians, ultimately enhancing diagnostic accuracy and therapeutic results.

The Art of Anaesthetizing Massive and Dangerous Creatures

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinarians’ most critical duties. Unlike routine procedures at traditional veterinary clinics, sedating a lion, rhino, or king cobra demands careful preparation, specialised apparatus, and nerves of steel. The stakes are exceptionally significant: miscalculate the dosage for a 2-tonne rhinoceros 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 spent decades developing procedures that account for each animal’s distinctive biological makeup, body composition, and metabolic peculiarities.

The procedure begins well ahead of the syringe enters flesh. Veterinarians study the specific creature’s clinical background, liaise with international specialists, and determine baseline vital signs. They arrange themselves with precision, ensuring quick availability to emergency equipment in case problems develop. Once the anaesthetic takes effect, constant observation grows essential. Pulse, arterial tension, blood oxygen levels, and body temperature are monitored intensively. Post-operative phases require equally vigilant observation, as animals emerging from sedation can behave unpredictably—as Guardian photographer David Levene discovered when King Arthur the cobra rose up and spat straight towards him, despite the protective glass barrier.

Preparing the Future of Zoo Veterinarians

The expertise required to treat threatened animals at ZSL doesn’t materialise overnight. Aspiring zoo veterinarians complete extended periods of intensive training, beginning with traditional veterinary qualifications before specialising in wild and exotic animal medicine. ZSL’s well-regarded reputation attracts talented professionals from across the globe, many of whom complete mentored training under the organisation’s seasoned team. This hands-on education proves invaluable; theoretical learning alone cannot prepare a vet for the unpredictability of sedating a lion or diagnosing illness in a severely threatened species where every individual matters significantly to conservation work.

The veterinary team at ZSL actively contributes in professional development within the zoo sector, disseminating expertise through publications, conferences, and collaborative research projects. Young veterinarians benefit from exposure to diverse cases—from standard wellness examinations to emergency interventions—whilst working with specialists in pathology, microbiology, and molecular diagnostics. This cross-functional setting fosters innovation in veterinary medicine and ensures that emerging practitioners understand the wider implications of zoo medicine: balancing immediate animal welfare with long-term conservation goals and contributing to scientific understanding of species preservation.

• Guidance with seasoned ZSL veterinarians focusing on care of exotic animals and emergency response
• Exposure to state-of-the-art diagnostic tools and laboratory facilities for applied training
• Participation in cross-border research initiatives advancing zoo veterinary medicine standards
• Familiarity to a wide range of species needing tailored medical approaches and conservation-oriented care approaches