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 spent shadowing the charity’s elite veterinary team, capturing the extraordinary challenges of caring for some of the world’s most dangerous and endangered animals. From anaesthetising 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 navigate critical situations that few other professionals ever face. With only a handful of British zoos employing their own resident vets, ZSL’s five-strong veterinary team, six nurses, a pathologist and several specialists represent a rare breed of medical expertise—one that has pioneered animal welfare practices for 200 years.

A Year of Unprecedented Medical Challenges

David Levene’s extended photographic project uncovered the unpredictable nature of zoo veterinary work. On his second day, the documentarian found himself face-to-face with Bhanu, an Asiatic lion afflicted with persistent recurring 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 animal care specialists could perform a thorough examination. Whilst Bhanu was sedated, the vets seized the opportunity to carry out comprehensive health checks, encompassing careful examination of his teeth, which are essential for a carnivore’s wellbeing and survival in captivity.

Perhaps the most dramatic moment came when King Arthur, a young king cobra and the world’s longest venomous snake, received 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 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 extraordinarily dangerous patients with practiced care and unwavering professionalism.

• King cobra responds to anaesthetic with venom-spraying display
• Asiatic lion demands sedation for aural examination
• Veterinary team conducts multiple health checks during anaesthesia
• Zoo medicine requires expertise with rare and dangerous species

The Professionals Who Keep Threatened Wildlife Alive

The veterinary staff at ZSL constitutes one of Britain’s most specialised medical workforces. With five fully trained veterinarians, six veterinary nurses, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity operates what few UK zoos can match: a comprehensive, in-house medical facility. This integrated approach allows the team to manage the intricate health demands of creatures spanning from dormice to rhinoceroses. Each specialist brings vital skills, whether diagnosing obscure parasitic infections, analysing genetic material or performing intricate surgical procedures on animals worth millions to international conservation efforts.

The challenges these specialists deal with are distinctly unique. Relocating a anaesthetised rhino demands thorough planning and advanced apparatus. Sedating a dormouse requires precise dosing for an animal weighing mere grams. Managing the care of a venomous snake demands understanding its behavioral patterns and physical makeup in ways that relatively few veterinarians experience. The ZSL group continually needs to innovate, drawing on decades of accumulated knowledge whilst adapting their approaches to specific creatures. Their work extends far beyond routine check-ups; they are guardians of some of the planet’s most endangered species, where a single animal’s survival can bear major preservation implications.

From Original Pioneers to Contemporary Medicine

ZSL’s focus on animal wellbeing extends back two centuries. The journals of Charles Spooner, the zoo’s original “medical attendant,” provide among the earliest written evidence of veterinary care in Britain. Spooner managed a lion cub named Nelson affected by mange, teething troubles and a life-threatening ulcer on his lower jaw. Through careful treatment—opening the ulcer and administering daily doses of zinc sulphate—Spooner saved the cub’s life, setting a legacy of compassionate and innovative veterinary care that continues today.

This historical foundation has influenced modern ZSL veterinary practice. The principles Spooner pioneered—meticulous observation, innovative solutions and unwavering dedication to individual animals—remain core to the team’s approach. Over two centuries, ZSL vets have regularly extended boundaries in veterinary care and animal welfare, publishing research and developing techniques now adopted globally. As the zoo marks its bicentenary, its veterinary team stands as a enduring monument to two hundred years of innovative leadership in exotic animal medicine.

Precise Surgical Intervention on the Earth’s Rarest Animals

Every surgical operation performed at ZSL represents a carefully weighed hazard with far-reaching significant 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 unique characteristics.

The complexity grows significantly when handling creatures whose physical structure differs radically from domesticated animals. A rhino’s circulatory system responds unpredictably to sedation. A snake’s metabolism processes anaesthetic agents at rates that challenge established procedures. A dormouse’s tiny body leaves virtually no margin for error in drug dosing. The ZSL veterinary team has created tailored approaches and observation technology to navigate these challenges, often pioneering approaches that eventually become standard practice across zoo facilities worldwide.

• Anaesthetising dormice requires exact micrograms of meticulously formulated pharmaceutical solutions.
• King cobras demand safe housing protocols during recuperation following sedation procedures.
• Rhino relocations necessitate specialised apparatus and integrated multi-agency operations.
• Dental examinations on carnivores reveal key markers of comprehensive health condition.
• Post-operative monitoring involves 24-hour watchful care by specialist animal care staff.

The Emotional Connection Between Animal Carers and Creatures

Behind every successful medical procedure lies a profound relationship between caregiver and creature. Zookeepers like Tara Humphrey spend countless hours observing their charges, identifying subtle behavioural shifts that indicate illness or distress. When Bhanu the Asiatic lion was put under anaesthetic for his ear examination, Humphrey seized the rare opportunity for tactile contact, embracing the impressive animal whilst he lay unconscious. These bonds go beyond mere emotion; they embody the thorough understanding that enables keepers to deliver vital details to veterinarians, ultimately enhancing diagnostic accuracy and treatment outcomes.

The Art of Anaesthetizing Large and Hazardous Animals

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinarians’ most essential duties. Unlike standard operations at conventional animal hospitals, anaesthetising a lion, rhino, or king cobra demands meticulous planning, specialised apparatus, and unwavering composure. The stakes are extraordinarily high: miscalculate the dosage 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 faces genuine mortal danger. ZSL’s veterinarians have devoted years developing procedures that take into account each species’ distinctive biological makeup, body composition, and metabolic peculiarities.

The process begins long before the syringe penetrates flesh. Veterinarians study the individual animal’s medical history, consult with overseas experts, and establish baseline vital signs. They arrange themselves with precision, ensuring quick availability to emergency equipment should complications arise. Once the anaesthetic takes effect, continuous monitoring becomes paramount. Pulse, blood pressure, oxygen saturation, and body temperature are tracked relentlessly. Post-operative phases require comparably careful 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 directly at him, despite the protective glass barrier.

Preparing the Upcoming Generation of Zoo Veterinarians

The specialised knowledge needed to treat threatened animals at ZSL does not develop overnight. Aspiring zoo veterinarians undergo years of demanding training, beginning with standard 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 experienced team. This practical education proves to be invaluable; textbook knowledge alone cannot prepare a vet for the unpredictability of anaesthetising a lion or identifying illness in a critically endangered 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 peer-reviewed articles, industry conferences, and joint research initiatives. 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 multidisciplinary environment fosters innovation in animal healthcare and ensures that emerging practitioners understand the wider implications of zoo medicine: reconciling immediate creature wellbeing with sustained species preservation objectives and advancing scientific understanding of species preservation.

• Training from seasoned ZSL veterinarians specialising in care of exotic animals and emergency procedures
• Access to advanced diagnostic equipment and pathology laboratories for practical training
• Involvement in cross-border research initiatives improving standards in zoo veterinary medicine
• Exposure to various animal species needing customised treatment methods and treatment approaches centred on conservation