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 captured a year spent shadowing the charity’s specialist animal doctors, capturing the extraordinary challenges of caring for some of the world’s most dangerous and endangered animals. From sedating a king cobra that reacted to sedation with a toxic discharge to examining an Asiatic lion’s distinctly constricted ear canal, the vets, nurses and specialists working across ZSL’s facilities in London and Whipsnade manage critical situations that most other medical practitioners ever face. With just a small number of British zoos having their own resident vets, ZSL’s team of five vets, 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 200 years.

A Year of Remarkable Clinical Pressures

David Levene’s year-long photographic project revealed the unpredictable nature of zoo veterinary work. On his second visit, the photographer found himself face-to-face with Bhanu, an Asiatic lion afflicted with chronic recurrent ear infections that had resulted in an exceptionally constricted ear canal. The condition necessitated a general anaesthetic—always a last resort in zoo medicine—so the animal care specialists could conduct a thorough examination. Whilst Bhanu was under sedation, the vets seized the opportunity to perform comprehensive health checks, including detailed inspection of his teeth, which are absolutely crucial for a meat-eater’s survival and wellbeing in captivity.

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

• King cobra displays anaesthetic with venom-spraying display
• Asiatic lion requires sedation for ear canal examination
• Veterinary team carries out several health assessments during anaesthesia
• Zoo medicine requires expertise with rare and dangerous species

The Professionals That Maintain Endangered Species Alive

The veterinary staff 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 maintains what most British zoos can provide: a comprehensive on-site medical facility. This multidisciplinary approach allows the team to address the complex health needs of creatures ranging from dormice to rhinoceroses. Each specialist provides vital skills, whether diagnosing obscure parasitic infections, examining genetic material or executing sophisticated surgical procedures on animals worth millions to global conservation efforts.

The obstacles these professionals face are distinctly uncommon. Shifting a sedated rhino demands careful planning and advanced apparatus. Anaesthetising a dormouse calls for accurate medication levels for an animal tipping the scales at mere grams. Managing the care of a venomous snake demands understanding its behavioral patterns and physical makeup in ways that scarcely any veterinarians come across. The ZSL unit continually needs to develop new approaches, leveraging decades of accumulated knowledge whilst adapting their methods to specific creatures. 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 Historic Innovators to Modern Healthcare

ZSL’s focus on animal welfare dates back two centuries. The journals of Charles Spooner, the zoo’s first “medical attendant,” give some of the first documented records of veterinary medicine in Britain. Spooner managed a young cub named Nelson affected by mange infection, dental issues and a serious ulcer on his lower jaw. Through careful treatment—draining the ulcer and administering daily doses of zinc sulphate—Spooner preserved the cub’s life, founding a record of innovative, compassionate animal medicine that remains in place today.

This longstanding foundation has influenced modern ZSL veterinary practice. The principles Spooner pioneered—precise scrutiny, creative problem-solving and unwavering dedication 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, producing research and creating techniques now embraced internationally. As the zoo marks its bicentenary, its veterinary team stands as a enduring monument to two hundred years of pioneering excellence in exotic animal medicine.

Surgical Precision on the Earth’s Rarest Creatures

Every surgical procedure undertaken at ZSL represents a carefully weighed hazard with far-reaching significant consequences. When a vet performs surgery on an species at risk, they are not simply treating an individual patient—they are protecting an entire population whose continued existence could rely on that one individual. The team must balance the imperative to intervene with the inherent dangers 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 individual quirks.

The intricacy grows significantly when dealing with creatures whose anatomy varies considerably from tame species. A rhino’s circulatory system behaves inconsistently to sedative drugs. A snake’s metabolic rate breaks down anaesthetic agents at rates that defy standard protocols. A dormouse’s diminutive physique leaves scarcely any allowance for error in drug dosing. The ZSL veterinary team has established bespoke methods and surveillance equipment to address these difficulties, often pioneering approaches that subsequently become common procedure across zoological organisations 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 collaborative multi-department operations.
• Dental examinations on carnivores reveal crucial indicators of overall health status.
• Post-operative monitoring involves continuous surveillance by dedicated veterinary nursing staff.

The Deep Bond Between Animal Carers and Animals

Behind every successful medical intervention lies a profound relationship between caregiver and creature. Zookeepers like Tara Humphrey devote extensive time observing their charges, recognising subtle behavioural shifts that indicate illness or distress. When Bhanu the Asiatic lion was anaesthetised for his ear examination, Humphrey seized the rare opportunity for physical affection, embracing the impressive animal whilst he lay asleep. These bonds transcend sentimentality; they embody the deep knowledge that allows keepers to deliver vital details to veterinarians, ultimately enhancing diagnostic accuracy and treatment outcomes.

The Science of Anaesthetizing Large and Hazardous Creatures

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinarians’ most essential duties. Unlike routine procedures at conventional animal hospitals, anaesthetising a lion, rhino, or king cobra demands meticulous planning, specialist equipment, and unwavering composure. The stakes are exceptionally significant: get the dose wrong for a two-tonne rhino 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 devoted years developing procedures that account for each species’ distinctive biological makeup, body composition, and metabolic characteristics.

The process begins well ahead of the syringe penetrates flesh. Veterinarians study the specific creature’s medical history, consult with overseas experts, and establish baseline vital signs. They arrange themselves with precision, ensuring rapid access to critical apparatus in case problems develop. Once the sedative begins working, constant observation grows essential. Heart rate, blood pressure, blood oxygen levels, and body temperature are monitored intensively. Recovery periods require comparably careful 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, in spite of the protective glass barrier.

Preparing the Upcoming Generation of Zoo Veterinarians

The expertise needed to care for threatened animals at ZSL does not emerge overnight. Aspiring zoo veterinarians complete years of demanding training, beginning with standard veterinary qualifications before focusing in wild and exotic animal medicine. ZSL’s strong reputation attracts talented professionals from throughout the globe, many of whom undertake supervised placements under the organisation’s experienced team. This practical education demonstrates as invaluable; textbook knowledge alone cannot prepare a vet for the variability of sedating a lion or identifying illness in a severely threatened species where every individual matters greatly to conservation work.

The veterinary team at ZSL actively contributes in career advancement within the zoo sector, sharing their accumulated knowledge through peer-reviewed articles, industry conferences, and joint research initiatives. Young veterinarians benefit from exposure to diverse cases—from routine health checks to emergency interventions—whilst working alongside specialists in pathology, microbiology, and molecular diagnostics. This multidisciplinary environment fosters innovation in veterinary medicine and ensures that junior veterinarians understand the wider implications of zoo medicine: balancing immediate animal welfare with long-term conservation goals and advancing scientific understanding of species preservation.

• Mentorship with experienced ZSL veterinarians specialising in exotic animal care and emergency response
• Exposure to state-of-the-art diagnostic equipment and pathology laboratories for applied training
• Involvement in collaborative research projects enhancing zoo veterinary medicine standards
• Familiarity to diverse species needing tailored medical approaches and conservation-oriented care approaches