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 following the charity’s elite veterinary team, capturing the extraordinary challenges of treating 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 London and Whipsnade zoos navigate critical situations that few other professionals ever encounter. With just a small number of British zoos employing their own resident vets, ZSL’s team of five vets, six nurses, a pathologist and multiple specialist experts constitute a unique form of veterinary knowledge—one that has pioneered animal welfare practices for two centuries.

A Year of Exceptional Clinical Pressures

David Levene’s year-long photo documentation uncovered the unpredictable nature of zoo veterinary work. On his second day, the photographer encountered Bhanu, an Asiatic lion suffering from chronic recurrent ear infections that had resulted in an unusually narrow ear canal. The condition required a general anaesthetic—always a last resort in zoo medicine—so the veterinary team could perform a comprehensive assessment. Whilst Bhanu was sedated, the vets took the chance 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, was given his anaesthetic injection. The reptile responded 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 displays anaesthetic with venomous spitting display
• Asiatic lion demands sedation for aural examination
• Veterinary team performs several health assessments during anaesthesia
• Zoo medicine demands expertise with rare and dangerous species

Those Specialists Who Keep Endangered Species In Existence

The veterinary staff at ZSL constitutes one of Britain’s most highly specialised workforces. With five fully trained veterinarians, six nursing professionals, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity maintains what most British zoos can match: a full in-house medical facility. This integrated approach enables the team to tackle the complex health needs of creatures ranging from dormice to rhinoceroses. Each specialist brings vital skills, whether detecting rare parasitic infections, examining genetic material or conducting complex surgical procedures on animals worth millions to global conservation efforts.

The obstacles these experts encounter are truly uncommon. Shifting a sedated rhino demands thorough planning and specialised tools. Anaesthetising a dormouse demands exact pharmaceutical measurement for an animal tipping the scales at mere grams. Providing treatment to a venomous snake demands understanding its behavioral patterns and physical makeup in ways that few veterinarians ever encounter. The ZSL unit continually needs to develop new approaches, drawing on extensive accumulated knowledge whilst adjusting their techniques to each animal. Their work goes well past regular assessments; they are guardians of some of the world’s most endangered species, where a individual creature’s survival can hold major preservation implications.

From Historic Innovators to Present-day Healthcare

ZSL’s commitment to the welfare of animals dates back 200 years. The journals of Charles Spooner, the zoo’s first “medical attendant,” give among the earliest documented records of veterinary care in Britain. Spooner managed a young cub named Nelson suffering from mange infection, teething troubles and a potentially fatal ulcer on his lower jaw. Through careful treatment—opening the ulcer and giving daily doses of zinc sulphate—Spooner rescued the cub’s life, establishing a legacy of compassionate and innovative veterinary care that continues today.

This longstanding foundation has informed modern ZSL veterinary practice. The principles Spooner pioneered—meticulous observation, creative problem-solving and resolute devotion to individual animals—remain fundamental to the team’s approach. Over two centuries, ZSL vets have consistently pushed boundaries in animal wellbeing and health, publishing research and developing techniques now embraced internationally. 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.

Surgical Precision on the World’s Most Endangered Creatures

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 safeguarding a species whose survival may depend 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 decades of accumulated knowledge, joint investigations with overseas specialists, and an deep knowledge of the individual’s clinical background and unique characteristics.

The complexity grows significantly when dealing with creatures whose anatomy deviates substantially from domestic livestock. A rhino’s cardiovascular system behaves inconsistently to anaesthetic administration. A snake’s metabolic rate metabolises anaesthetic agents at rates that defy standard protocols. A dormouse’s small frame leaves scarcely any allowance for error in pharmaceutical administration. The ZSL veterinary experts has created tailored approaches and observation technology to address these difficulties, often developing novel methods that later 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 specialist equipment and coordinated multi-team operations.
• Dental examinations on carnivores reveal vital signs of general wellbeing.
• Post-operative monitoring involves continuous surveillance by experienced veterinary support staff.

The Deep Bond Between Animal Carers and Creatures

Behind every successful medical procedure lies a deep relationship between keeper and creature. Zookeepers like Tara Humphrey spend countless hours observing their animals, identifying subtle behavioural shifts that signal illness or distress. When Bhanu the Asian lion was put under anaesthetic for his ear check, Humphrey seized the rare opportunity for physical affection, cuddling the impressive animal whilst he lay asleep. These connections transcend sentimentality; they represent the thorough understanding that allows keepers to provide crucial information to veterinarians, ultimately improving diagnostic accuracy and treatment outcomes.

The Science of Anaesthetizing Massive and Dangerous Creatures

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinary team’s most critical duties. Unlike routine procedures at traditional veterinary clinics, sedating a lion, rhino, or king cobra demands careful preparation, specialised apparatus, and unwavering composure. The stakes are exceptionally significant: get the dose wrong for a 2-tonne rhinoceros and the animal’s cardiovascular 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 take into account each species’ unique physiology, physical structure, and metabolic characteristics.

The procedure begins well ahead of the syringe penetrates flesh. Veterinarians examine the individual animal’s clinical background, consult with international specialists, and determine baseline vital signs. They position themselves strategically, guaranteeing quick availability to critical apparatus in case problems develop. Once the sedative begins working, continuous monitoring grows essential. Heart rate, blood pressure, oxygen saturation, and core heat are tracked relentlessly. Post-operative phases demand comparably careful observation, as animals emerging from sedation can act erratically—as Guardian photographer David Levene found 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 care for threatened animals at ZSL doesn’t materialise overnight. Prospective zoo veterinarians complete extended periods of demanding training, beginning with standard veterinary qualifications before focusing in exotic and wild animal medicine. ZSL’s established reputation draws skilled professionals from throughout the globe, many of whom complete apprenticeships and mentorships under the charity’s seasoned team. This practical education proves invaluable; theoretical learning alone cannot equip a vet for the unpredictability of anaesthetising a lion or identifying illness in a critically endangered species where every individual matters significantly to conservation work.

The veterinary team at ZSL plays a key role in professional development within the zoo sector, sharing their accumulated knowledge through publications, conferences, and collaborative research projects. Young veterinarians benefit from exposure to diverse cases—from standard wellness examinations to urgent clinical procedures—whilst working alongside specialists in pathology, microbiology, and molecular diagnostics. This multidisciplinary environment fosters innovation in animal healthcare and ensures that junior veterinarians understand the wider implications of zoo medicine: reconciling immediate creature wellbeing with sustained species preservation objectives and advancing scientific understanding of species preservation.

• Mentorship under seasoned ZSL veterinarians specialising in care of exotic animals and emergency procedures
• Exposure to cutting-edge diagnostic tools and laboratory facilities for practical training
• Engagement in cross-border research initiatives improving zoo veterinary medicine standards
• Exposure to diverse species demanding species-specific medical strategies and conservation-focused treatment strategies