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 documented a year following the charity’s elite veterinary team, capturing 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 distinctly constricted ear canal, the vets, nurses and specialists employed at ZSL’s London and Whipsnade zoos manage critical situations that most other medical practitioners ever encounter. With only a handful of British zoos having their own resident vets, ZSL’s team of five vets, six nurses, a animal pathologist and several specialists represent a rare breed of medical expertise—one that has established standards in animal care for two centuries.

A Year of Exceptional Clinical Pressures

David Levene’s year-long photo documentation revealed the unpredictability of zoo veterinary work. On his second day, the documentarian found himself face-to-face with Bhanu, an Asiatic lion suffering from persistent recurring ear infections that had left him with an exceptionally constricted ear canal. The condition necessitated a full anaesthetic—always a last resort in zoo medicine—so the veterinary team could perform a thorough examination. Whilst Bhanu was sedated, the vets seized the opportunity to perform detailed health assessments, including detailed inspection of his teeth, which are essential for a carnivore’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, received 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 exceptionally perilous patients with practiced care and unwavering professionalism.

• King cobra responds to anaesthetic with venomous spitting display
• Asiatic lion demands sedation for ear canal examination
• Veterinary team carries out multiple health checks during anaesthesia
• Zoo medicine calls for expertise with rare and dangerous species

The Experts Responsible for Keeping At-Risk Animals Alive

The animal health team at ZSL exemplifies one of Britain’s most specialist medical workforces. With five fully qualified veterinarians, six nursing professionals, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity runs what few British zoos can match: a comprehensive, in-house medical facility. This multidisciplinary approach enables the team to tackle the intricate health demands of creatures ranging from dormice to rhinoceroses. Each specialist provides essential knowledge, whether diagnosing obscure parasitic infections, examining genetic material or executing sophisticated surgical procedures on animals worth millions to international conservation efforts.

The difficulties these experts encounter are genuinely exceptional. Shifting a unconscious rhino demands meticulous preparation and specialist equipment. Sedating a dormouse requires accurate medication levels for an animal weighing mere grams. Managing the care of a venomous snake requires grasping its behavioral patterns and physical makeup in ways that scarcely any veterinarians experience. The ZSL group continually needs to innovate, utilising years of accumulated knowledge whilst modifying their methods to each animal. Their work extends far beyond routine check-ups; they are guardians of some of the world’s most endangered species, where a single animal’s survival can hold significant ecological implications.

From Original Founders to Present-day Medicine

ZSL’s focus on animal wellbeing extends back 200 years. The journals of Charles Spooner, the zoo’s original “medical attendant,” give among the earliest written evidence of veterinary care in Britain. Spooner managed a young cub named Nelson affected by mange infection, dental issues and a life-threatening ulcer on his lower jaw. Through meticulous care—draining the ulcer and giving regular zinc sulphate treatments—Spooner saved the cub’s life, founding a record of innovative and compassionate animal medicine that persists today.

This longstanding foundation has informed modern ZSL veterinary practice. The principles Spooner pioneered—careful examination, creative problem-solving and resolute devotion to individual animals—remain core to the team’s approach. Over two centuries, ZSL vets have continually advanced boundaries in animal health and welfare, producing research and creating techniques now adopted globally. As the zoo marks its bicentenary, its veterinary team stands as a living testament to two hundred years of pioneering excellence in exotic animal medicine.

Surgical Precision on the World’s Most Endangered Creatures

Every surgical procedure undertaken at ZSL represents a carefully weighed hazard with far-reaching significant consequences. When a veterinarian operates on an endangered animal, they are not simply treating an individual patient—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 operative setbacks. Each decision is informed by years of gathered knowledge, collaborative research with overseas specialists, and an intimate understanding of the individual’s clinical background and unique characteristics.

The complexity grows significantly when handling creatures whose bodily composition differs radically from domesticated animals. A rhino’s circulatory system behaves inconsistently to anaesthetic administration. A snake’s metabolism breaks down anaesthetic agents at rates that exceed conventional guidelines. A dormouse’s small frame leaves almost no room for error in drug dosing. The ZSL veterinary team has created bespoke methods and observation technology to overcome these obstacles, often establishing innovative techniques that subsequently become standard practice across zoological institutions worldwide.

• Anaesthetising dormice requires accurate micrograms of meticulously formulated pharmaceutical solutions.
• King cobras demand secure containment protocols during recovery from sedation procedures.
• Rhino relocations necessitate specialised apparatus and collaborative multi-department operations.
• Dental examinations on carnivores reveal key markers of overall health status.
• Post-operative monitoring involves round-the-clock observation by experienced veterinary support staff.

The Affectionate Relationship Between Keepers and Creatures

Behind every effective medical procedure lies a profound relationship between caregiver and creature. Zookeepers like Tara Humphrey devote extensive time observing their charges, identifying subtle behavioural shifts that indicate illness or distress. When Bhanu the Asian lion was put under anaesthetic for his ear check, Humphrey seized the rare opportunity for physical affection, embracing the impressive animal whilst he lay asleep. These bonds transcend sentimentality; they embody the thorough understanding that allows keepers to deliver vital details to veterinarians, ultimately improving diagnostic accuracy and treatment outcomes.

The Art of Anaesthetizing Massive and Dangerous Animals

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinarians’ most critical responsibilities. Unlike routine procedures at traditional veterinary clinics, anaesthetising a lion, rhino, or king cobra demands careful preparation, specialised apparatus, and unwavering composure. The stakes are exceptionally significant: get the dose wrong for a two-tonne rhino and the animal’s cardiovascular system may fail; give insufficient medication to a venomous snake and the keeper encounters real risk of death. ZSL’s veterinarians have spent decades refining protocols that account for each animal’s unique physiology, body composition, and metabolic peculiarities.

The procedure begins long before the syringe enters flesh. Veterinarians examine the individual animal’s medical history, consult with international specialists, and establish baseline vital signs. They position themselves strategically, ensuring quick availability to emergency equipment in case problems develop. Once the sedative begins working, constant observation grows essential. Heart rate, blood pressure, oxygen saturation, and body temperature are monitored intensively. Post-operative phases demand comparably careful 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 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 emerge overnight. Prospective zoo veterinarians complete years of demanding training, starting with traditional veterinary qualifications before specialising in wild and exotic animal medicine. ZSL’s established reputation attracts accomplished professionals from throughout the globe, many of whom undertake apprenticeships and mentorships under the charity’s experienced team. This direct education proves invaluable; academic study alone cannot prepare a vet for the unpredictability of anaesthetising a lion or identifying illness in a at-risk species where each animal matters greatly to wildlife conservation.

The veterinary team at ZSL plays a key role 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 routine health checks to urgent clinical procedures—whilst working with specialists in pathology, microbiology, and molecular diagnostics. This cross-functional setting fosters innovation in animal healthcare and ensures that emerging practitioners understand the wider implications of zoo medicine: reconciling immediate animal welfare with sustained species preservation objectives and contributing to scientific understanding of species preservation.

• Mentorship under expert ZSL veterinarians with expertise in care of exotic animals and emergency response
• Access to advanced diagnostic equipment and pathology laboratories for applied training
• Participation in collaborative research projects enhancing standards in zoo veterinary medicine
• Exposure to various animal species requiring species-specific medical strategies and conservation-focused treatment strategies