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, recording the remarkable difficulties of treating some of the world’s most dangerous and endangered animals. From sedating a king cobra that responded to anaesthetic with a toxic discharge to assessing an Asiatic lion’s unusually narrow ear canal, the vets, nurses and specialists employed at ZSL’s London and Whipsnade zoos manage medical emergencies that few other professionals ever encounter. With only a handful of British zoos employing their own resident vets, ZSL’s team of five vets, six nurses, a animal pathologist and several specialists constitute a unique form of veterinary knowledge—one that has established standards in animal care for 200 years.

A Year of Unprecedented Medical Challenges

David Levene’s year-long photo documentation uncovered 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 full anaesthetic—always a final option in zoo medicine—so the veterinary team 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 absolutely crucial for a carnivore’s survival and wellbeing 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 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 practiced care and unwavering professionalism.

• King cobra displays anaesthetic with venom-spraying display
• Asiatic lion needs sedation for aural examination
• Veterinary team conducts multiple health checks during anaesthesia
• Zoo medicine demands expertise with rare and dangerous species

The Experts Responsible for Keeping Endangered Species In Existence

The animal health team at ZSL represents one of Britain’s most specialised medical workforces. With five fully qualified veterinarians, six veterinary nurses, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity runs what most British zoos can match: a full in-house medical facility. This multidisciplinary approach allows the team to address the complicated medical requirements of creatures spanning from dormice to rhinoceroses. Each specialist contributes vital skills, whether identifying unusual parasitic infections, examining genetic material or conducting complex surgical procedures on animals worth millions to global conservation efforts.

The challenges these experts face are genuinely exceptional. Moving a sedated rhino necessitates careful planning and advanced apparatus. Sedating a dormouse demands accurate medication levels for an animal weighing mere grams. Managing the care of a venomous snake requires grasping its behaviour and physiology in ways that relatively few veterinarians come across. The ZSL team continually needs to innovate, drawing on extensive accumulated knowledge whilst adapting their approaches to specific creatures. Their work extends far beyond routine check-ups; they are custodians of some of the planet’s most endangered species, where a individual creature’s survival can hold major preservation implications.

From Historic Pioneers to Present-day Medical Practice

ZSL’s focus on animal welfare extends back 200 years. The journals of Charles Spooner, the zoo’s first “medical attendant,” provide some of the first written evidence of animal medical care in Britain. Spooner managed a young lion cub named Nelson afflicted with mange, teething troubles and a serious ulcer on his jaw. Through meticulous care—draining the ulcer and giving regular zinc sulphate treatments—Spooner rescued the cub’s life, establishing a record of innovative and compassionate animal medicine that remains in place today.

This enduring foundation has informed modern ZSL veterinary practice. The principles Spooner pioneered—precise scrutiny, resourceful approaches and unwavering dedication to individual animals—remain core to the team’s approach. Over two centuries, ZSL vets have consistently pushed boundaries in animal health and welfare, disseminating findings and establishing techniques now adopted globally. As the zoo celebrates its bicentenary, its veterinary team stands as a lasting tribute to two hundred years of pioneering excellence in exotic animal medicine.

Precise Surgical Intervention on the Planet’s Rarest Species

Every surgical procedure undertaken at ZSL represents a carefully weighed hazard with far-reaching significant consequences. When a veterinarian operates on an species at risk, they are not simply caring for a single creature—they are safeguarding a species whose survival may depend on that single life. The team must balance the imperative to intervene with the fundamental risks of anaesthesia, infection and surgical complications. Each decision is informed by decades of accumulated knowledge, joint investigations with international colleagues, and an deep knowledge of the specific animal’s medical history and individual quirks.

The intricacy escalates dramatically when dealing with creatures whose physical structure varies considerably from domesticated animals. A rhino’s cardiovascular system behaves inconsistently to sedation. A snake’s metabolic rate processes anaesthetic agents at rates that challenge established procedures. A dormouse’s small frame leaves scarcely any allowance for error in drug dosing. The ZSL veterinary staff has developed specialised techniques and monitoring systems to overcome these obstacles, often pioneering approaches that eventually become common procedure across zoological institutions 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 expert-level gear and coordinated multi-team operations.
• Dental examinations on carnivores reveal crucial indicators of comprehensive health condition.
• Post-operative monitoring involves continuous surveillance by experienced veterinary support staff.

The Deep Bond Between Keepers and Animals

Behind every successful medical intervention lies a profound relationship between keeper and animal. Zookeepers like Tara Humphrey spend countless hours observing their charges, recognising minor changes in behaviour that indicate illness or discomfort. When Bhanu the Asian lion was anaesthetised for his ear examination, Humphrey took the uncommon chance for physical affection, embracing the impressive animal whilst he lay unconscious. These connections transcend sentimentality; they represent the thorough understanding that allows keepers to deliver vital details to veterinarians, ultimately enhancing diagnostic accuracy and therapeutic results.

The Science of Anaesthetizing Large and Hazardous Wildlife

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinarians’ most critical responsibilities. Unlike standard operations at traditional veterinary clinics, anaesthetising a lion, rhino, or king cobra demands meticulous planning, specialist equipment, and unwavering composure. The stakes are extraordinarily high: miscalculate the dosage for a two-tonne rhino and the animal’s heart and circulatory system may fail; give insufficient medication to a venomous snake and the keeper faces genuine mortal danger. ZSL’s veterinarians have devoted years refining protocols that take into account each animal’s unique physiology, body composition, and metabolic peculiarities.

The process begins well ahead of the syringe penetrates flesh. Veterinarians study the specific creature’s clinical background, consult with overseas experts, and establish baseline vital signs. They arrange themselves with precision, guaranteeing quick availability to emergency equipment should complications arise. Once the anaesthetic takes effect, constant observation becomes paramount. Pulse, arterial tension, blood oxygen levels, and core heat are tracked relentlessly. Post-operative phases require equally vigilant observation, as animals coming out of anaesthesia can behave unpredictably—as Guardian photographer David Levene found when King Arthur the cobra reared up and spat directly at him, despite the protective glass barrier.

Preparing the Next Generation of Zoo Veterinarians

The skills required to treat threatened animals at ZSL doesn’t materialise overnight. Prospective zoo veterinarians undergo years of intensive training, starting with traditional veterinary qualifications before specialising in wild and exotic animal medicine. ZSL’s well-regarded reputation attracts skilled professionals from throughout the globe, many of whom complete mentored training under the organisation’s experienced team. This direct education proves to be invaluable; academic study alone cannot prepare a vet for the variability of anaesthetising a lion or diagnosing illness in a severely threatened species where each animal matters profoundly to conservation work.

The veterinary team at ZSL actively contributes in career advancement within the zoo sector, disseminating expertise through peer-reviewed articles, industry conferences, and joint research initiatives. Young veterinarians benefit from involvement with diverse cases—from routine health checks to urgent clinical procedures—whilst working alongside specialists in pathology, microbiology, and molecular diagnostics. This multidisciplinary environment drives advancement in veterinary medicine and ensures that emerging practitioners understand the wider implications of zoo medicine: balancing immediate creature wellbeing with sustained species preservation objectives and advancing scientific understanding of species preservation.

• Guidance under seasoned ZSL veterinarians with expertise in exotic animal care and emergency procedures
• Access to cutting-edge diagnostic tools and pathology laboratories for applied training
• Participation in collaborative research projects advancing zoo veterinary medicine standards
• Familiarity to a wide range of species requiring customised treatment methods and treatment approaches centred on conservation