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 specialist animal doctors, capturing the extraordinary challenges of caring for some of the world’s rarest and most vulnerable animals. From anaesthetising a king cobra that reacted to sedation with a venomous spray to assessing an Asiatic lion’s distinctly constricted ear canal, the vets, nurses and specialists employed at ZSL’s London and Whipsnade zoos manage critical situations that few other professionals ever encounter. With just a small number of British zoos employing their own in-house veterinarians, ZSL’s five-strong veterinary team, six nurses, a pathologist and several specialists represent a rare breed of medical expertise—one that has pioneered standards in animal care for two centuries.

A Year of Exceptional Healthcare Difficulties

David Levene’s extended photo documentation uncovered the unpredictability of zoo animal medicine. On his second visit, the photographer encountered Bhanu, an Asiatic lion suffering from persistent recurring ear infections that had resulted in an exceptionally constricted ear canal. The condition required a full anaesthetic—always a last resort in zoo medicine—so the animal care specialists could conduct a comprehensive assessment. Whilst Bhanu was under sedation, the vets seized the opportunity to carry out detailed health assessments, including detailed inspection of his teeth, which are essential for a meat-eater’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, 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 injected 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 reacts to anaesthetic with venomous spitting display
• Asiatic lion needs sedation for aural examination
• Veterinary team carries out several health assessments during anaesthesia
• Zoo medicine requires expertise with exotic and hazardous species

The Professionals Who Keep At-Risk Animals Alive

The animal health team at ZSL exemplifies one of Britain’s most highly specialised workforces. With five certified veterinarians, six veterinary nurses, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity operates what few British zoos can replicate: a comprehensive, in-house medical facility. This multidisciplinary approach enables 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, examining genetic material or conducting complex surgical procedures on animals worth millions to worldwide conservation efforts.

The obstacles these professionals deal with are truly exceptional. Relocating a sedated rhino requires careful planning and advanced apparatus. Anaesthetising a dormouse calls for exact pharmaceutical measurement for an animal tipping the scales at mere grams. Providing treatment to a venomous snake requires understanding its behaviour and physiology in ways that scarcely any veterinarians ever encounter. The ZSL team has to regularly adapt their methods, utilising years of accumulated knowledge whilst adapting their methods to individual animals. Their work goes well past standard examinations; they are guardians of some of the planet’s most endangered species, where a single animal’s survival can bear significant ecological implications.

From Original Founders to Modern Healthcare

ZSL’s focus on animal welfare stretches back 200 years. The journals of Charles Spooner, the zoo’s original “medical attendant,” provide some of the earliest documented records of animal medical care in Britain. Spooner cared for a young cub named Nelson affected by mange infection, teething troubles and a serious ulcer on his lower jaw. Through meticulous care—draining the ulcer and applying daily zinc sulphate solutions—Spooner saved the cub’s life, creating a legacy of innovative and compassionate animal medicine that persists today.

This enduring foundation has influenced modern ZSL veterinary practice. The principles Spooner pioneered—meticulous observation, creative problem-solving and steadfast commitment to individual animals—remain central to the team’s approach. Over two centuries, ZSL vets have continually advanced boundaries in veterinary care and animal welfare, publishing research and developing techniques now embraced internationally. 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 Creatures

Every surgical operation performed at ZSL represents a carefully weighed hazard with potentially enormous consequences. When a veterinarian operates 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 fundamental risks of anaesthesia, infection and surgical complications. Each decision is informed by decades of accumulated knowledge, collaborative research with overseas specialists, and an intimate understanding of the specific animal’s medical history and unique characteristics.

The difficulty escalates dramatically when handling creatures whose anatomy deviates substantially from domesticated animals. A rhino’s cardiovascular system behaves inconsistently to anaesthetic administration. A snake’s metabolic rate metabolises anaesthetic agents at rates that challenge established procedures. A dormouse’s small frame leaves almost no room for error in drug dosing. The ZSL veterinary experts has created bespoke methods and monitoring systems to navigate these challenges, often establishing innovative techniques that later become established protocol across zoological institutions worldwide.

• Anaesthetising dormice requires precise micrograms of carefully calculated pharmaceutical solutions.
• King cobras demand secure containment protocols during recuperation following sedation procedures.
• Rhino relocations necessitate expert-level gear and integrated multi-agency operations.
• Dental examinations on carnivores reveal vital signs of comprehensive health condition.
• Post-operative monitoring involves continuous surveillance by dedicated veterinary nursing staff.

The Deep Bond Between Keepers and Creatures

Behind every effective medical intervention lies a profound relationship between caregiver and creature. Zookeepers like Tara Humphrey spend countless hours observing their charges, identifying minor changes in behaviour that signal illness or discomfort. When Bhanu the Asiatic lion was put under anaesthetic for his ear check, Humphrey took the uncommon chance for physical affection, cuddling the magnificent beast whilst he lay asleep. These bonds transcend sentimentality; they embody the deep knowledge that enables keepers to deliver vital details to veterinarians, ultimately enhancing diagnostic accuracy and therapeutic results.

The Practice of Anaesthetising Big and Potentially Dangerous Creatures

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinary team’s most essential duties. 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: miscalculate the dosage for a 2-tonne rhinoceros and the animal’s heart and circulatory system may collapse; give insufficient medication to a venomous snake and the keeper encounters real risk of death. ZSL’s veterinarians have spent decades developing procedures that take into account each animal’s distinctive biological makeup, body composition, and metabolic peculiarities.

The process begins long before the syringe penetrates flesh. Veterinarians examine the individual animal’s medical history, consult with overseas experts, and establish standard physiological measurements. They position themselves strategically, guaranteeing quick availability to emergency equipment in case problems develop. Once the sedative begins working, continuous monitoring grows essential. Heart rate, blood pressure, oxygen saturation, and body temperature are tracked relentlessly. Recovery periods demand equally vigilant 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 Future of Zoo Veterinarians

The specialised knowledge required to care for threatened animals at ZSL does not emerge overnight. Aspiring zoo veterinarians undergo extended periods of intensive 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 organisation’s experienced team. This practical education proves invaluable; theoretical learning alone cannot equip a vet for the variability of anaesthetising a lion or identifying illness in a critically endangered species where each animal matters significantly to conservation efforts.

The veterinary team at ZSL actively contributes in professional development within the zoo sector, sharing their accumulated knowledge through publications, conferences, and collaborative research projects. Young veterinarians gain valuable experience through involvement with diverse cases—from standard wellness examinations to urgent clinical procedures—whilst working alongside specialists in pathology, microbiology, and molecular diagnostics. This cross-functional setting fosters innovation in veterinary medicine and ensures that emerging practitioners understand the broader context of zoo medicine: balancing immediate creature wellbeing with sustained species preservation objectives and contributing to scientific understanding of species preservation.

• Mentorship with experienced ZSL veterinarians focusing on exotic animal care and urgent intervention
• Exposure to state-of-the-art diagnostic equipment and pathology laboratories for practical training
• Involvement in international research collaborations improving zoo veterinary medicine standards
• Familiarity to diverse species demanding species-specific medical strategies and conservation-oriented care approaches