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 remarkable difficulties of treating some of the world’s most dangerous and endangered animals. From sedating a king cobra that reacted to sedation with a toxic discharge to assessing an Asiatic lion’s distinctly constricted ear canal, the vets, nurses and specialists working across ZSL’s London and Whipsnade zoos manage critical situations that most other medical practitioners ever face. With only a handful of British zoos employing their own resident vets, ZSL’s five-strong veterinary team, nursing staff of six, a pathologist and multiple specialist experts represent a unique form of veterinary knowledge—one that has established animal welfare practices for two centuries.

A Year of Exceptional Medical Challenges

David Levene’s extended photographic project revealed the unpredictability of zoo animal medicine. On his second day, the documentarian encountered Bhanu, an Asiatic lion suffering from persistent recurring ear infections that had left him with an exceptionally constricted ear canal. The condition required a general 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 took the chance to carry out comprehensive health checks, encompassing careful examination 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 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 exceptionally perilous patients with practiced care and unwavering professionalism.

• King cobra reacts to anaesthetic with venom-spraying display
• Asiatic lion requires sedation for aural examination
• Veterinary team conducts several health assessments during anaesthesia
• Zoo medicine calls for expertise with exotic and hazardous species

The Experts Responsible for Keeping At-Risk Animals Alive

The veterinary staff at ZSL constitutes one of Britain’s most highly specialised 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 replicate: a comprehensive, in-house medical facility. This multidisciplinary model enables the team to manage the complicated medical requirements of creatures spanning from dormice to rhinoceroses. Each specialist brings essential knowledge, whether identifying unusual parasitic infections, analysing genetic material or conducting complex surgical procedures on animals worth millions to global conservation efforts.

The difficulties these professionals encounter are genuinely exceptional. Moving a unconscious rhino demands meticulous preparation and advanced apparatus. Anaesthetising a dormouse requires accurate medication levels for an animal tipping the scales at mere grams. Managing the care of a venomous snake requires grasping its behaviour and physiology in ways that relatively few veterinarians ever encounter. The ZSL group has to regularly adapt their methods, drawing on years of accumulated knowledge whilst modifying their techniques to individual animals. Their work extends far beyond standard examinations; they are custodians of some of the Earth’s endangered species, where a single animal’s survival can carry major preservation implications.

From Original Innovators to Present-day Medicine

ZSL’s commitment to animal welfare dates back 200 years. The journals of Charles Spooner, the zoo’s first “medical attendant,” give among the earliest documented records of veterinary medicine in Britain. Spooner cared for a young cub named Nelson affected by mange, teething troubles and a serious ulcer on his jaw. Through careful intervention—opening the ulcer and applying daily doses of zinc sulphate—Spooner rescued the cub’s life, creating a legacy of compassionate and innovative veterinary care that remains in place 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 core to the team’s approach. Over two centuries, ZSL vets have regularly extended boundaries in animal wellbeing and health, producing research and creating techniques now implemented worldwide. As the zoo commemorates its bicentenary, its veterinary team stands as a lasting tribute to two hundred years of pioneering excellence in exotic animal medicine.

Precision Surgery on the World’s Most Endangered Creatures

Every surgical procedure undertaken 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 survival may depend on that one individual. The team must balance the imperative to intervene with the inherent dangers of anaesthesia, infection and surgical complications. 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 difficulty increases substantially when dealing with creatures whose anatomy differs radically from tame species. A rhino’s cardiovascular system behaves inconsistently to sedative drugs. A snake’s metabolism processes anaesthetic agents at rates that defy standard protocols. A dormouse’s diminutive physique leaves virtually no margin for error in medication dosage. The ZSL veterinary team has developed tailored approaches and monitoring systems to overcome these obstacles, often pioneering approaches that subsequently become established protocol across zoological organisations worldwide.

• Anaesthetising dormice requires precise micrograms of meticulously formulated pharmaceutical solutions.
• King cobras demand safe housing protocols during recovery from sedation procedures.
• Rhino relocations necessitate specialised apparatus and coordinated multi-team operations.
• Dental examinations on carnivores reveal crucial indicators of comprehensive health condition.
• Post-operative monitoring involves continuous surveillance by specialist animal care staff.

The Affectionate Relationship Between Animal Carers and Creatures

Behind every effective medical intervention lies a deep relationship between keeper and animal. Zookeepers like Tara Humphrey devote extensive time observing their animals, identifying subtle behavioural shifts that indicate illness or distress. When Bhanu the Asian lion was anaesthetised for his ear examination, Humphrey took the uncommon chance for tactile contact, embracing the impressive animal whilst he lay unconscious. 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 Anaesthetizing Massive and Dangerous Creatures

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinarians’ most essential responsibilities. Unlike standard operations at traditional veterinary clinics, sedating a lion, rhino, or king cobra demands careful preparation, specialist equipment, and nerves of steel. The stakes are exceptionally significant: get the dose wrong for a 2-tonne rhinoceros and the animal’s cardiovascular system may collapse; give insufficient medication to a venomous snake and the keeper encounters genuine mortal danger. ZSL’s veterinarians have devoted years refining protocols that account for each animal’s unique physiology, body composition, and metabolic characteristics.

The process commences long before the syringe enters flesh. Veterinarians study the specific creature’s clinical background, liaise with overseas experts, and establish standard physiological measurements. They arrange themselves with precision, guaranteeing rapid access to critical apparatus should complications arise. Once the anaesthetic takes effect, continuous monitoring becomes paramount. Heart rate, arterial tension, blood oxygen levels, and core heat are tracked relentlessly. Post-operative phases require 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 straight towards him, in spite of the protective glass barrier.

Training the Upcoming Generation of Zoo Veterinarians

The expertise needed to care for endangered animals at ZSL doesn’t materialise overnight. Aspiring zoo veterinarians undergo years of demanding training, starting with standard veterinary qualifications before specialising in exotic and wild animal medicine. ZSL’s strong reputation draws accomplished professionals from across the globe, many of whom undertake supervised placements under the charity’s experienced team. This practical education demonstrates as invaluable; academic study alone cannot equip a vet for the variability of anaesthetising a lion or identifying illness in a critically endangered species where each animal matters profoundly to wildlife conservation.

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 gain valuable experience through exposure to 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 wider implications of zoo medicine: balancing immediate animal welfare with long-term conservation goals and advancing scientific understanding of species preservation.

• Training with seasoned ZSL veterinarians focusing on exotic animal care and emergency response
• Exposure to cutting-edge diagnostic equipment and laboratory facilities for applied training
• Involvement in collaborative research projects enhancing standards in zoo veterinary medicine
• Exposure to a wide range of species demanding tailored medical approaches and treatment approaches centred on conservation