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, recording the extraordinary challenges of caring for some of the world’s rarest and most vulnerable animals. From sedating a king cobra that reacted to sedation with a venomous spray to assessing an Asiatic lion’s unusually narrow ear canal, the vets, nurses and specialists working across ZSL’s facilities in London and Whipsnade manage critical situations that few other professionals ever encounter. With only a handful of British zoos employing their own resident vets, 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 established standards in animal care for 200 years.

A Year of Unprecedented Clinical Pressures

David Levene’s extended photographic project uncovered the unpredictability of zoo veterinary work. On his second visit, the photographer encountered Bhanu, an Asiatic lion suffering from chronic recurrent 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 veterinary team could perform a thorough examination. Whilst Bhanu was under sedation, the vets took the chance to perform detailed health assessments, encompassing careful examination of his teeth, which are essential for a meat-eater’s wellbeing and survival in captivity.

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

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

The Professionals Who Keep At-Risk Animals In Existence

The veterinary staff at ZSL represents one of Britain’s most specialist medical workforces. With five fully qualified veterinarians, six nursing staff, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity maintains what few UK zoos can provide: a full in-house medical facility. This multidisciplinary model allows the team to manage the intricate health demands of creatures spanning from dormice to rhinoceroses. Each specialist contributes crucial expertise, whether diagnosing obscure parasitic infections, examining genetic material or conducting complex surgical procedures on animals worth millions to international conservation efforts.

The difficulties these experts face are genuinely exceptional. Shifting a anaesthetised rhino necessitates careful planning and specialist equipment. Sedating a dormouse calls for precise dosing for an animal weighing mere grams. Treating a venomous snake requires grasping its behavioral patterns and physical makeup in ways that scarcely any veterinarians ever encounter. The ZSL group continually needs to adapt their methods, leveraging extensive accumulated knowledge whilst adapting their techniques to individual animals. Their work transcends standard examinations; they are custodians of some of the Earth’s endangered species, where a single animal’s survival can hold significant ecological implications.

From Early Founders to Present-day Healthcare

ZSL’s commitment to animal welfare dates back 200 years. The journals of Charles Spooner, the zoo’s original “medical attendant,” offer among the earliest written accounts of veterinary medicine in Britain. Spooner cared for a young cub named Nelson suffering from mange infection, dental issues and a life-threatening ulcer on his jaw. Through careful treatment—opening the ulcer and giving daily zinc sulphate solutions—Spooner saved the cub’s life, establishing a record of compassionate and innovative veterinary care that remains in place today.

This historical foundation has influenced modern ZSL veterinary practice. The principles Spooner pioneered—careful examination, innovative solutions and steadfast commitment to individual animals—remain central to the team’s approach. Over two centuries, ZSL vets have consistently pushed boundaries in veterinary care and animal welfare, disseminating findings and establishing techniques now embraced internationally. As the zoo celebrates 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 Earth’s Rarest 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 protecting an entire population whose survival may depend on that one individual. The team must weigh the need to act with the fundamental risks of anaesthesia, infection and surgical complications. Each choice draws upon by decades of accumulated knowledge, joint investigations with overseas specialists, and an intimate understanding of the specific animal’s medical history and individual quirks.

The difficulty increases substantially when working with creatures whose bodily composition differs radically from tame species. A rhino’s circulatory system reacts unpredictably to sedative drugs. A snake’s metabolism processes anaesthetic agents at rates that exceed conventional guidelines. A dormouse’s tiny body leaves almost no room for error in drug dosing. The ZSL veterinary team has created specialised techniques and monitoring systems to address these difficulties, often developing novel methods that subsequently become standard practice across zoo facilities worldwide.

• Anaesthetising dormice requires exact micrograms of meticulously formulated pharmaceutical solutions.
• King cobras demand robust enclosure protocols during recovery from sedation procedures.
• Rhino relocations necessitate expert-level gear and integrated multi-agency operations.
• Dental examinations on carnivores reveal key markers of overall health status.
• Post-operative monitoring involves round-the-clock observation by dedicated veterinary nursing staff.

The Affectionate Relationship Between Keepers and Creatures

Behind every effective medical procedure lies a profound relationship between caregiver and animal. Zookeepers like Tara Humphrey devote extensive time observing their animals, identifying subtle behavioural shifts that indicate illness or discomfort. When Bhanu the Asiatic lion was anaesthetised for his ear check, Humphrey seized the rare opportunity for physical affection, cuddling the impressive animal whilst he lay asleep. These connections go beyond mere emotion; they represent the deep knowledge that enables keepers to provide crucial information to veterinarians, ultimately improving accuracy of diagnosis and treatment outcomes.

The Science of Anaesthetising Massive and Dangerous Animals

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinarians’ most critical duties. Unlike standard operations at traditional veterinary clinics, anaesthetising 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 cardiovascular system may fail; give insufficient medication to a venomous snake and the keeper faces genuine mortal danger. ZSL’s veterinarians have spent decades refining protocols that account for each species’ distinctive biological makeup, body composition, and metabolic peculiarities.

The procedure begins well ahead of the syringe enters flesh. Veterinarians study the specific creature’s medical history, consult with international specialists, and determine standard physiological measurements. They arrange themselves with precision, ensuring rapid access to critical apparatus should complications arise. Once the sedative begins working, constant observation grows essential. Heart rate, blood pressure, blood oxygen levels, and body temperature are monitored intensively. Post-operative phases require equally vigilant observation, as animals emerging from sedation can behave unpredictably—as Guardian photographer David Levene found when King Arthur the cobra reared up and spat straight towards him, despite the protective glass barrier.

Training the Future of Zoo Veterinarians

The skills needed to treat threatened animals at ZSL does not develop overnight. Prospective zoo veterinarians complete years of intensive training, beginning with traditional 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 supervised placements under the charity’s seasoned team. This practical education proves to be invaluable; textbook knowledge alone cannot prepare a vet for the unpredictability of sedating a lion or diagnosing illness in a critically endangered species where each animal matters significantly to wildlife conservation.

The veterinary team at ZSL actively contributes 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 standard wellness examinations to emergency interventions—whilst working alongside 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: reconciling immediate animal welfare with sustained species preservation objectives and advancing scientific understanding of species preservation.

• Training under expert ZSL veterinarians focusing on exotic animal care and urgent intervention
• Exposure to advanced diagnostic tools and pathology laboratories for applied training
• Participation in cross-border research initiatives improving zoo veterinary medicine standards
• Exposure to a wide range of species needing species-specific medical strategies and treatment approaches centred on conservation