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 captured a year following the charity’s specialist animal doctors, recording the remarkable difficulties of caring for some of the world’s most dangerous and endangered animals. From sedating a king cobra that reacted to sedation with a venomous spray to assessing an Asiatic lion’s unusually narrow ear canal, the vets, nurses and specialists working across ZSL’s facilities in London and Whipsnade navigate critical situations that few other professionals ever encounter. With just a small number of British zoos employing their own resident vets, ZSL’s five-strong veterinary team, nursing staff of six, a pathologist and multiple specialist experts constitute a rare breed of medical expertise—one that has pioneered standards in animal care for two centuries.

A Year of Unprecedented Healthcare Difficulties

David Levene’s extended photographic project revealed the unpredictability of zoo veterinary work. On his second day, the photographer found himself face-to-face with Bhanu, an Asiatic lion afflicted with persistent recurring ear infections that had left him with an unusually narrow ear canal. The condition required a full anaesthetic—always a final option 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 careful examination of his teeth, which are essential 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 responded 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 exceptionally perilous patients with practiced care and unwavering professionalism.

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

The Experts That Maintain At-Risk Animals Alive

The veterinary team at ZSL exemplifies one of Britain’s most highly specialised workforces. With five fully qualified veterinarians, six nursing professionals, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity maintains what few British zoos can replicate: a comprehensive, in-house medical facility. This multidisciplinary model enables the team to address the complicated medical requirements of creatures spanning from dormice to rhinoceroses. Each specialist contributes essential knowledge, whether identifying unusual parasitic infections, studying genetic material or conducting complex surgical procedures on animals worth millions to international conservation efforts.

The challenges these professionals deal with are distinctly uncommon. Relocating a unconscious rhino requires thorough planning and specialist equipment. Anaesthetising a dormouse calls for exact pharmaceutical measurement for an animal tipping the scales at mere grams. Providing treatment to a venomous snake requires comprehending its behavioral patterns and physical makeup in ways that few veterinarians ever encounter. The ZSL team has to regularly adapt their methods, leveraging decades of accumulated knowledge whilst adjusting their methods to specific creatures. Their work transcends regular assessments; they are custodians of some of the planet’s most endangered species, where a lone animal’s survival can hold significant ecological implications.

From Historic Pioneers to Present-day Medicine

ZSL’s commitment to the welfare of animals stretches back 200 years. The journals of Charles Spooner, the zoo’s original “medical attendant,” provide some of the earliest written evidence of veterinary medicine in Britain. Spooner cared for a young lion cub named Nelson suffering from mange, dental issues and a potentially fatal ulcer on his lower jaw. Through careful intervention—draining the ulcer and administering regular zinc sulphate treatments—Spooner saved the cub’s life, establishing a record of innovative and compassionate animal medicine that continues today.

This enduring foundation has informed modern ZSL veterinary practice. The principles Spooner pioneered—meticulous observation, innovative solutions and unwavering dedication to individual animals—remain central to the team’s approach. Over two centuries, ZSL vets have regularly extended boundaries in animal wellbeing and health, producing research and creating techniques now adopted globally. As the zoo commemorates its bicentenary, its veterinary team stands as a lasting tribute to two hundred years of innovative leadership in exotic animal medicine.

Precision Surgery on the Planet’s Rarest Creatures

Every surgical operation performed 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 caring for a single creature—they are safeguarding a species whose continued existence could rely on that one individual. The team must weigh the need to act with the fundamental risks of anaesthesia, infection and surgical complications. Each choice draws upon by decades of accumulated knowledge, collaborative research with international colleagues, and an deep knowledge of the individual’s clinical background and individual quirks.

The intricacy increases substantially when working with creatures whose physical structure deviates substantially from domestic livestock. 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 drug dosing. The ZSL veterinary team has created tailored approaches and surveillance equipment to address these difficulties, often establishing innovative techniques that later become common procedure across zoological institutions worldwide.

• Anaesthetising dormice requires accurate micrograms of carefully calculated pharmaceutical solutions.
• King cobras demand safe housing protocols during recuperation following sedation procedures.
• Rhino relocations necessitate expert-level gear and collaborative multi-department operations.
• Dental examinations on carnivores reveal vital signs of comprehensive health condition.
• Post-operative monitoring involves round-the-clock observation by experienced veterinary support staff.

The Emotional Connection Between Animal Carers and Creatures

Behind every successful medical intervention lies a deep relationship between keeper and animal. Zookeepers like Tara Humphrey devote extensive time observing their animals, recognising minor changes in behaviour that signal 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 impressive animal whilst he lay asleep. These bonds go beyond mere emotion; they embody the deep knowledge that enables keepers to provide crucial information to veterinarians, ultimately enhancing accuracy of diagnosis and treatment outcomes.

The Science of Anaesthetising Big and Potentially Dangerous Animals

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinary team’s most critical duties. Unlike standard operations at conventional animal hospitals, anaesthetising a lion, rhino, or king cobra demands careful preparation, specialist equipment, and nerves of steel. The stakes are extraordinarily high: miscalculate the dosage for a 2-tonne rhinoceros and the animal’s heart and circulatory system may fail; give insufficient medication to a venomous snake and the keeper encounters real risk of death. ZSL’s veterinarians have spent decades developing procedures that take into account each species’ distinctive biological makeup, body composition, and metabolic peculiarities.

The procedure commences well ahead of the syringe penetrates flesh. Veterinarians study the individual animal’s medical history, liaise with overseas experts, and determine baseline vital signs. They arrange themselves with precision, ensuring rapid access to critical apparatus should complications arise. Once the sedative begins working, constant observation becomes paramount. Pulse, arterial tension, oxygen saturation, and body temperature are tracked relentlessly. Post-operative phases demand equally vigilant 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, in spite of the protective glass barrier.

Training the Next Generation of Zoo Veterinarians

The specialised knowledge required to treat endangered animals at ZSL does not emerge overnight. Aspiring zoo veterinarians complete extended periods of demanding training, beginning with conventional 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 mentored training under the charity’s seasoned team. This hands-on education proves to be invaluable; theoretical learning alone cannot equip a vet for the uncertainty of sedating a lion or identifying illness in a at-risk species where every individual matters significantly to wildlife conservation.

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 gain valuable experience through involvement with diverse cases—from standard wellness examinations to urgent clinical procedures—whilst working with specialists in pathology, microbiology, and molecular diagnostics. This multidisciplinary environment fosters innovation in animal healthcare and ensures that emerging practitioners understand the wider implications of zoo medicine: reconciling immediate animal welfare with sustained species preservation objectives and contributing to scientific understanding of species preservation.

• Guidance under seasoned ZSL veterinarians specialising in care of exotic animals and urgent intervention
• Access to state-of-the-art diagnostic equipment and pathology laboratories for practical training
• Participation in collaborative research projects advancing zoo veterinary medicine standards
• Familiarity to a wide range of species needing customised treatment methods and treatment approaches centred on conservation