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 remarkable difficulties of caring for some of the world’s rarest and most vulnerable animals. From anaesthetising a king cobra that responded to anaesthetic with a toxic discharge to assessing an Asiatic lion’s distinctly constricted ear canal, the vets, nurses and specialists employed at ZSL’s facilities in London and Whipsnade manage medical emergencies that few other professionals ever face. With only a handful of British zoos employing their own in-house veterinarians, ZSL’s team of five vets, nursing staff of six, a animal pathologist and multiple specialist experts represent a rare breed of medical expertise—one that has pioneered animal welfare practices for 200 years.

A Year of Unprecedented Clinical Pressures

David Levene’s year-long photo documentation uncovered the unpredictable nature of zoo veterinary work. On his second visit, the documentarian encountered Bhanu, an Asiatic lion afflicted with chronic recurrent ear infections that had left him with an exceptionally constricted ear canal. The condition required a full 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 perform comprehensive health checks, encompassing careful examination of his teeth, which are absolutely crucial for a carnivore’s wellbeing and survival in captivity.

Perhaps the most striking 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 prove fatal to an elephant, yet the ZSL team handles such exceptionally perilous patients with practiced care and unwavering professionalism.

• King cobra displays anaesthetic with venom-spraying display
• Asiatic lion needs sedation for ear canal examination
• Veterinary team conducts several health assessments during anaesthesia
• Zoo medicine requires expertise with exotic and hazardous species

The Experts Responsible for Keeping Endangered Species Alive

The veterinary staff at ZSL constitutes one of Britain’s most specialised medical workforces. With five fully trained veterinarians, six nursing professionals, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity operates what few British zoos can match: a full in-house medical facility. This multidisciplinary model permits the team to tackle the intricate health demands of creatures spanning from dormice to rhinoceroses. Each specialist brings vital skills, whether diagnosing obscure parasitic infections, studying genetic material or conducting complex surgical procedures on animals worth millions to global conservation efforts.

The obstacles these experts face are distinctly exceptional. Shifting a unconscious rhino requires meticulous preparation and advanced apparatus. Anaesthetising a dormouse demands precise dosing for an animal tipping the scales at mere grams. Providing treatment to a venomous snake necessitates comprehending its behavioral patterns and physical makeup in ways that few veterinarians ever encounter. The ZSL unit continually needs to innovate, leveraging extensive accumulated knowledge whilst adjusting their approaches to individual animals. Their work transcends standard examinations; they are stewards of some of the Earth’s endangered species, where a lone animal’s survival can carry significant ecological implications.

From Original Founders to Contemporary Medical Practice

ZSL’s commitment to animal wellbeing stretches back two centuries. The journals of Charles Spooner, the zoo’s first “medical attendant,” give among the earliest written accounts of veterinary medicine in Britain. Spooner treated a young cub named Nelson suffering from mange infection, dental issues and a potentially fatal ulcer on his jaw. Through careful intervention—draining the ulcer and administering daily zinc sulphate solutions—Spooner rescued the cub’s life, creating a legacy of compassionate and innovative veterinary care that persists today.

This enduring foundation has shaped modern ZSL veterinary practice. The principles Spooner pioneered—careful examination, creative problem-solving and unwavering dedication to individual animals—remain core 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 adopted globally. As the zoo commemorates its bicentenary, its veterinary team stands as a living testament to two hundred years of pioneering excellence in exotic animal medicine.

Precision Surgery on the Planet’s Rarest Species

Every surgical operation performed at ZSL represents a carefully weighed hazard with far-reaching significant consequences. When a vet performs surgery on an endangered animal, they are not simply treating an individual patient—they are protecting an entire population whose survival may depend on that one individual. The team must balance the imperative to intervene with the fundamental risks of anaesthesia, infection and operative setbacks. Each choice draws upon by decades of accumulated knowledge, collaborative research with international colleagues, and an intimate understanding of the specific animal’s medical history and individual quirks.

The intricacy increases substantially when dealing with creatures whose bodily composition deviates substantially from tame species. A rhino’s cardiovascular system reacts unpredictably to anaesthetic administration. A snake’s metabolic rate metabolises anaesthetic agents at rates that challenge established procedures. A dormouse’s diminutive physique leaves virtually no margin for error in drug dosing. The ZSL veterinary staff 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 carefully calculated pharmaceutical solutions.
• King cobras demand safe housing 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 round-the-clock observation by experienced veterinary support staff.

The Deep Bond Between Animal Carers and Creatures

Behind every effective medical procedure lies a profound relationship between caregiver and creature. 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 anaesthetised for his ear check, Humphrey took the uncommon chance for tactile contact, cuddling the impressive animal whilst he lay asleep. These connections transcend sentimentality; they represent the deep knowledge that enables keepers to deliver vital details to veterinarians, ultimately improving accuracy of diagnosis and therapeutic results.

The Art of Anaesthetising Massive and Dangerous Animals

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinary team’s most critical responsibilities. Unlike routine procedures at traditional veterinary clinics, sedating a lion, rhino, or king cobra demands careful preparation, specialist equipment, and unwavering composure. The stakes are exceptionally significant: get the dose wrong for a 2-tonne rhinoceros and the animal’s heart and circulatory system may fail; administer too little to a venomous snake and the keeper encounters genuine mortal danger. ZSL’s veterinarians have spent decades developing procedures that take into account each species’ distinctive biological makeup, physical structure, and metabolic peculiarities.

The process commences long before the syringe penetrates flesh. Veterinarians examine the individual animal’s clinical background, consult with overseas experts, and determine baseline vital signs. They position themselves strategically, guaranteeing rapid access to critical apparatus in case problems develop. Once the sedative begins working, constant observation becomes paramount. Pulse, blood pressure, blood oxygen levels, and core heat are monitored intensively. Recovery periods demand equally vigilant observation, as animals emerging from sedation can behave unpredictably—as Guardian photographer David Levene discovered when King Arthur the cobra reared up and spat straight towards him, despite the protective glass barrier.

Educating the Next Generation of Zoo Veterinarians

The specialised knowledge needed to care for endangered animals at ZSL does not develop overnight. Prospective zoo veterinarians complete years of intensive training, starting with conventional veterinary qualifications before specialising in exotic and wild animal medicine. ZSL’s established reputation attracts skilled professionals from across the globe, many of whom complete apprenticeships and mentorships under the charity’s seasoned team. This practical education proves to be invaluable; theoretical learning alone cannot equip a vet for the unpredictability of anaesthetising a lion or identifying illness in a critically endangered species where each animal matters significantly to conservation work.

The veterinary team at ZSL plays a key role in professional development within the zoo sector, disseminating expertise through peer-reviewed articles, industry conferences, and joint research initiatives. Young veterinarians gain valuable experience through involvement with diverse cases—from routine health checks to emergency interventions—whilst working alongside specialists in pathology, microbiology, and molecular diagnostics. This multidisciplinary environment drives advancement 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 with expert ZSL veterinarians focusing on care of exotic animals and emergency procedures
• Exposure to cutting-edge diagnostic equipment and pathology laboratories for hands-on learning
• Participation in collaborative research projects improving zoo veterinary medicine standards
• Familiarity to a wide range of species demanding tailored medical approaches and conservation-oriented care approaches