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 captured 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 examining an Asiatic lion’s unusually narrow ear canal, the vets, nurses and specialists working across ZSL’s London and Whipsnade zoos manage medical emergencies that most other medical practitioners ever encounter. With only a handful 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 animal welfare practices for 200 years.

A Year of Unprecedented Medical Challenges

David Levene’s year-long photographic project revealed the unpredictable nature of zoo animal medicine. On his second visit, the documentarian found himself face-to-face with Bhanu, an Asiatic lion suffering from persistent recurring ear infections that had resulted in an exceptionally constricted ear canal. The condition necessitated a general anaesthetic—always a final option in zoo medicine—so the animal care specialists could conduct a thorough examination. Whilst Bhanu was sedated, the vets seized the opportunity to carry out comprehensive health checks, including careful examination of his teeth, which are essential for a meat-eater’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 extraordinarily dangerous patients with practised precision and unwavering professionalism.

• King cobra reacts to anaesthetic with venomous spitting display
• Asiatic lion demands sedation for ear canal examination
• Veterinary team performs several health assessments during anaesthesia
• Zoo medicine demands expertise with rare and dangerous species

Those Specialists Responsible for Keeping Endangered Species Thriving

The veterinary team at ZSL constitutes one of Britain’s most specialised medical workforces. With five certified veterinarians, six veterinary nurses, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity runs what few UK zoos can provide: a comprehensive, in-house medical facility. This multidisciplinary model enables the team to manage the complex health needs of creatures spanning from dormice to rhinoceroses. Each specialist brings crucial expertise, whether identifying unusual parasitic infections, analysing genetic material or executing sophisticated surgical procedures on animals worth millions to international conservation efforts.

The obstacles these professionals deal with are truly uncommon. Relocating a anaesthetised rhino requires thorough planning and specialised tools. Anaesthetising a dormouse calls for exact pharmaceutical measurement for an animal tipping the scales at mere grams. Treating a venomous snake requires grasping its behaviour and physiology in ways that scarcely any veterinarians come across. The ZSL unit continually needs to develop new approaches, drawing on extensive accumulated knowledge whilst modifying their techniques to specific creatures. Their work extends far beyond routine check-ups; they are stewards of some of the planet’s most endangered species, where a single animal’s survival can carry significant ecological implications.

From Early Pioneers to Present-day Healthcare

ZSL’s focus on animal welfare extends back 200 years. The journals of Charles Spooner, the zoo’s first “medical attendant,” offer among the earliest written evidence of veterinary medicine in Britain. Spooner treated a young lion cub named Nelson afflicted with mange, teething troubles and a serious ulcer on his jaw. Through careful treatment—opening the ulcer and applying daily zinc sulphate solutions—Spooner preserved the cub’s life, creating a record of innovative and compassionate animal medicine that continues today.

This enduring foundation has shaped modern ZSL veterinary practice. The principles Spooner pioneered—precise scrutiny, innovative solutions and unwavering dedication to individual animals—remain central to the team’s approach. Over two centuries, ZSL vets have continually advanced boundaries in animal wellbeing and health, publishing research and developing techniques now implemented worldwide. As the zoo marks its bicentenary, its veterinary team stands as a living testament to two hundred years of innovative leadership in exotic animal medicine.

Precision Surgery on the Earth’s Rarest Creatures

Every surgical operation performed at ZSL represents a calculated risk with potentially enormous 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 surgical complications. 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 intricacy grows significantly when handling creatures whose physical structure differs radically from domestic livestock. A rhino’s cardiovascular system responds unpredictably to sedative drugs. A snake’s metabolic rate processes anaesthetic agents at rates that exceed conventional guidelines. A dormouse’s diminutive physique leaves virtually no margin for error in pharmaceutical administration. The ZSL veterinary experts has created bespoke methods and surveillance equipment to address these difficulties, often pioneering approaches that eventually become standard practice across zoo facilities worldwide.

• Anaesthetising dormice requires accurate micrograms of meticulously formulated pharmaceutical solutions.
• King cobras demand robust enclosure protocols during recovery from sedation procedures.
• Rhino relocations necessitate specialised apparatus and collaborative multi-department operations.
• Dental examinations on carnivores reveal key markers of general wellbeing.
• Post-operative monitoring involves 24-hour watchful care by dedicated veterinary nursing staff.

The Emotional Connection Between Keepers and Animals

Behind every effective medical procedure lies a deep relationship between caregiver and animal. Zookeepers like Tara Humphrey spend countless hours observing their charges, identifying subtle behavioural shifts that indicate illness or discomfort. When Bhanu the Asiatic lion was put under anaesthetic for his ear check, Humphrey took the uncommon chance for tactile contact, cuddling the magnificent beast whilst he lay unconscious. These bonds transcend sentimentality; they represent the thorough understanding that enables keepers to deliver vital details to veterinarians, ultimately improving diagnostic accuracy and therapeutic results.

The Practice of Anaesthetizing Large and Hazardous Creatures

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinary team’s most essential duties. Unlike routine procedures at conventional animal hospitals, anaesthetising a lion, rhino, or king cobra demands meticulous planning, specialist equipment, and unwavering composure. The stakes are exceptionally significant: 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 genuine mortal danger. ZSL’s veterinarians have devoted years developing procedures that account for each species’ distinctive biological makeup, physical structure, and metabolic characteristics.

The process commences long before the syringe enters flesh. Veterinarians examine the individual animal’s clinical background, consult with overseas experts, and establish standard physiological measurements. They arrange themselves with precision, guaranteeing quick availability to critical apparatus in case problems develop. Once the sedative begins working, continuous monitoring becomes paramount. Heart rate, arterial tension, blood oxygen levels, and body temperature are monitored intensively. Post-operative phases demand 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.

Preparing the Upcoming Generation of Zoo Veterinarians

The expertise required to treat endangered animals at ZSL doesn’t materialise overnight. Aspiring zoo veterinarians complete years of demanding training, starting with conventional veterinary qualifications before specialising in exotic and wild animal medicine. ZSL’s strong reputation attracts talented professionals from across the globe, many of whom undertake supervised placements under the charity’s seasoned team. This direct education demonstrates as invaluable; academic study alone cannot equip a vet for the variability of sedating a lion or diagnosing illness in a severely threatened species where every individual matters profoundly to conservation efforts.

The veterinary team at ZSL plays a key role 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 routine health checks to emergency interventions—whilst working with specialists in pathology, microbiology, and molecular diagnostics. This cross-functional setting fosters innovation in animal healthcare and ensures that junior veterinarians understand the wider implications of zoo medicine: balancing immediate animal welfare with sustained species preservation objectives and contributing to scientific understanding of species preservation.

• Training from expert ZSL veterinarians specialising in exotic animal care and urgent intervention
• Access to state-of-the-art diagnostic equipment and pathology laboratories for hands-on learning
• Engagement in international research collaborations enhancing veterinary care standards for zoos
• Experience to various animal species needing customised treatment methods and conservation-focused treatment strategies