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 extraordinary challenges of caring for some of the world’s most dangerous and endangered animals. From sedating a king cobra that reacted to sedation 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 manage critical situations that few other professionals ever face. With only a handful of British zoos having their own in-house veterinarians, ZSL’s team of five vets, nursing staff of six, a animal pathologist and multiple specialist experts represent a unique form of veterinary knowledge—one that has pioneered animal welfare practices for 200 years.

A Year of Exceptional Medical Challenges

David Levene’s year-long photographic project revealed the unpredictable nature of zoo animal medicine. On his second visit, 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 general anaesthetic—always a last resort in zoo medicine—so the animal care specialists could conduct a comprehensive assessment. Whilst Bhanu was sedated, the vets seized the opportunity to perform comprehensive health checks, encompassing 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 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 practised precision and unwavering professionalism.

• King cobra displays anaesthetic with venomous spitting display
• Asiatic lion demands sedation for aural examination
• Veterinary team carries out multiple health checks during anaesthesia
• Zoo medicine demands expertise with rare and dangerous species

The Experts Responsible for Keeping Endangered Species In Existence

The veterinary staff at ZSL represents one of Britain’s most highly specialised workforces. With five fully qualified veterinarians, six veterinary nurses, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity runs what few British zoos can provide: a comprehensive on-site medical facility. This multidisciplinary model allows the team to address the complicated medical requirements of creatures extending from dormice to rhinoceroses. Each specialist brings crucial expertise, whether diagnosing obscure parasitic infections, analysing genetic material or executing sophisticated surgical procedures on animals worth millions to international conservation efforts.

The difficulties these specialists face are truly unique. Shifting a unconscious rhino necessitates meticulous preparation and specialist equipment. Sedating a dormouse demands precise dosing for an animal tipping the scales at mere grams. Treating a venomous snake requires comprehending its behaviour and physiology in ways that scarcely any veterinarians come across. The ZSL unit must constantly adapt their methods, drawing on extensive accumulated knowledge whilst modifying their techniques to specific creatures. Their work transcends routine check-ups; they are stewards of some of the planet’s most endangered species, where a lone animal’s survival can carry major preservation implications.

From Historic Pioneers to Contemporary Medicine

ZSL’s focus on animal wellbeing dates back two centuries. The journals of Charles Spooner, the zoo’s original “medical attendant,” offer among the earliest written evidence of veterinary care in Britain. Spooner cared for a lion cub named Nelson affected by mange, teething problems and a life-threatening ulcer on his lower jaw. Through meticulous care—opening the ulcer and giving daily doses of zinc sulphate—Spooner rescued the cub’s life, establishing a legacy of innovative, compassionate animal medicine that remains in place today.

This enduring foundation has influenced modern ZSL veterinary practice. The principles Spooner pioneered—careful examination, resourceful approaches and unwavering dedication to individual animals—remain central to the team’s approach. Over two centuries, ZSL vets have continually advanced boundaries in animal health and welfare, producing research and creating techniques now implemented worldwide. As the zoo marks its bicentenary, its veterinary team stands as a lasting tribute to two hundred years of innovative leadership in exotic animal medicine.

Precise Surgical Intervention on the Earth’s Rarest Species

Every surgical operation performed at ZSL represents a calculated risk with potentially enormous consequences. When a veterinarian operates on an endangered animal, they are not simply caring for a single creature—they are protecting an entire population whose continued existence could rely on that single life. The team must weigh the need to act with the fundamental risks of anaesthesia, infection and surgical complications. Each choice draws upon by years of gathered knowledge, collaborative research with overseas specialists, and an intimate understanding of the individual’s clinical background and unique characteristics.

The intricacy increases substantially when working with creatures whose anatomy deviates substantially from tame species. A rhino’s cardiovascular system responds unpredictably to sedative drugs. A snake’s metabolic rate breaks down anaesthetic agents at rates that challenge established procedures. A dormouse’s tiny body leaves scarcely any allowance for error in medication dosage. The ZSL veterinary team has created bespoke methods and observation technology to navigate these challenges, often establishing innovative techniques that eventually become common procedure across zoological institutions worldwide.

• Anaesthetising dormice requires exact micrograms of meticulously formulated pharmaceutical solutions.
• King cobras demand secure containment protocols during recovery from sedation procedures.
• Rhino relocations necessitate specialised apparatus and integrated multi-agency operations.
• Dental examinations on carnivores reveal crucial indicators of comprehensive health condition.
• Post-operative monitoring involves round-the-clock observation by specialist animal care staff.

The Affectionate Relationship Between Animal Carers and Animals

Behind every effective medical intervention lies a profound relationship between keeper and animal. Zookeepers like Tara Humphrey devote extensive time observing their animals, recognising subtle behavioural shifts that signal illness or discomfort. When Bhanu the Asiatic lion was put under anaesthetic for his ear examination, Humphrey seized the rare opportunity for tactile contact, cuddling the magnificent beast whilst he lay unconscious. These connections go beyond mere emotion; they represent the thorough understanding that allows keepers to deliver vital details to veterinarians, ultimately enhancing accuracy of diagnosis and therapeutic results.

The Practice of Anaesthetizing Massive and Dangerous Wildlife

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 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 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 spent decades refining protocols that take into account each species’ distinctive biological makeup, body composition, and metabolic characteristics.

The procedure begins well ahead of the syringe enters flesh. Veterinarians examine the individual animal’s clinical background, consult with international specialists, and determine baseline vital signs. They position themselves strategically, ensuring quick availability to emergency equipment in case problems develop. Once the sedative begins working, continuous monitoring grows essential. Pulse, arterial tension, oxygen saturation, and core heat are tracked relentlessly. Post-operative phases demand 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 directly at him, despite the protective glass barrier.

Preparing the Upcoming Generation of Zoo Veterinarians

The expertise required to treat threatened animals at ZSL does not develop overnight. Aspiring zoo veterinarians complete extended periods of rigorous training, starting with conventional veterinary qualifications before focusing in exotic and wild animal medicine. ZSL’s strong reputation draws talented professionals from across the globe, many of whom complete apprenticeships and mentorships under the charity’s seasoned team. This practical education proves invaluable; theoretical learning alone cannot prepare a vet for the unpredictability of anaesthetising a lion or diagnosing illness in a at-risk species where each animal matters profoundly to conservation work.

The veterinary team at ZSL actively contributes in career advancement within the zoo sector, disseminating expertise through peer-reviewed articles, industry conferences, and joint research initiatives. Young veterinarians benefit from involvement with diverse cases—from routine health checks to emergency interventions—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 broader context of zoo medicine: balancing immediate animal welfare with long-term conservation goals and advancing scientific understanding of species preservation.

• Mentorship under seasoned ZSL veterinarians specialising in exotic animal care and urgent intervention
• Exposure to advanced diagnostic equipment and laboratory facilities for hands-on learning
• Participation in international research collaborations advancing standards in zoo veterinary medicine
• Experience to a wide range of species demanding customised treatment methods and conservation-focused treatment strategies