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 following the charity’s specialist animal doctors, capturing the remarkable difficulties of treating some of the world’s most dangerous and endangered animals. From anaesthetising 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 working across ZSL’s facilities in London and Whipsnade navigate critical situations that most other medical practitioners ever encounter. With just a small number of British zoos having their own resident vets, ZSL’s team of five vets, six nurses, a 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 Remarkable Medical Challenges

David Levene’s extended photographic project uncovered the unpredictable nature of zoo animal medicine. On his second day, the photographer encountered Bhanu, an Asiatic lion suffering from chronic recurrent ear infections that had left him with an unusually narrow ear canal. The condition necessitated a full anaesthetic—always a last resort in zoo medicine—so the veterinary team could perform a comprehensive assessment. Whilst Bhanu was sedated, the vets seized the opportunity to carry out detailed health assessments, encompassing detailed inspection of his teeth, which are absolutely crucial for a meat-eater’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, received 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 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 demands sedation for aural examination
• Veterinary team conducts multiple health checks during anaesthesia
• Zoo medicine demands expertise with rare and dangerous species

The Professionals Who Keep Threatened Wildlife Alive

The veterinary staff at ZSL represents one of Britain’s most specialised medical workforces. With five certified veterinarians, six nursing professionals, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity maintains what most British zoos can provide: a comprehensive, in-house medical facility. This multidisciplinary model enables the team to manage the complex health needs of creatures extending from dormice to rhinoceroses. Each specialist contributes crucial expertise, whether detecting rare parasitic infections, studying genetic material or performing intricate surgical procedures on animals worth millions to international conservation efforts.

The obstacles these professionals face are distinctly uncommon. Moving a unconscious rhino requires meticulous preparation and specialised tools. Sedating a dormouse demands precise dosing for an animal weighing mere grams. Treating a venomous snake necessitates grasping its behaviour and physiology in ways that scarcely any veterinarians come across. The ZSL unit must constantly develop new approaches, utilising years of accumulated knowledge whilst modifying their methods to individual animals. Their work extends far beyond regular assessments; they are stewards of some of the planet’s most endangered species, where a single animal’s survival can bear significant ecological implications.

From Early Innovators to Present-day Medical Practice

ZSL’s dedication to animal wellbeing extends back two centuries. The journals of Charles Spooner, the zoo’s original “medical attendant,” give among the earliest written evidence of animal medical care in Britain. Spooner cared for a lion cub named Nelson affected by mange infection, teething troubles and a potentially fatal ulcer on his lower jaw. Through meticulous care—lancing the ulcer and giving regular zinc sulphate treatments—Spooner saved the cub’s life, establishing a legacy of compassionate and innovative veterinary care that remains in place today.

This longstanding foundation has influenced modern ZSL veterinary practice. The principles Spooner pioneered—careful examination, innovative solutions and unwavering dedication to individual animals—remain fundamental to the team’s approach. Over two centuries, ZSL vets have continually advanced boundaries in veterinary care and animal welfare, publishing research and developing techniques now implemented worldwide. As the zoo celebrates its bicentenary, its veterinary team stands as a lasting tribute to two hundred years of innovative leadership in exotic animal medicine.

Surgical Precision on the Earth’s Rarest Creatures

Every surgical operation performed at ZSL represents a carefully weighed hazard with far-reaching significant consequences. When a vet performs surgery on an endangered animal, they are not simply treating an individual patient—they are protecting an entire population 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 choice draws upon by years of gathered knowledge, joint investigations with overseas specialists, and an deep knowledge of the individual’s clinical background and individual quirks.

The complexity increases substantially when working with creatures whose bodily composition deviates substantially from tame species. A rhino’s cardiovascular system reacts unpredictably to sedation. A snake’s metabolic processes processes anaesthetic agents at rates that exceed conventional guidelines. A dormouse’s diminutive physique leaves scarcely any allowance for error in medication dosage. The ZSL veterinary staff has developed specialised techniques and monitoring systems to address these difficulties, often establishing innovative techniques that later become common procedure across zoo facilities worldwide.

• Anaesthetising dormice requires precise micrograms of meticulously formulated pharmaceutical solutions.
• King cobras demand robust enclosure protocols during recovery from sedation procedures.
• Rhino relocations necessitate specialist equipment and collaborative multi-department operations.
• Dental examinations on carnivores reveal key markers of comprehensive health condition.
• Post-operative monitoring involves 24-hour watchful care by dedicated veterinary nursing staff.

The Deep Bond Between Animal Carers and Animals

Behind every successful medical procedure lies a deep relationship between caregiver and animal. Zookeepers like Tara Humphrey spend countless hours observing their animals, identifying minor changes in behaviour that signal illness or discomfort. When Bhanu the Asiatic lion was put under anaesthetic for his ear examination, Humphrey took the uncommon chance for physical affection, cuddling the magnificent beast whilst he lay asleep. These connections transcend sentimentality; they represent the thorough understanding that enables keepers to provide crucial information to veterinarians, ultimately enhancing diagnostic accuracy and treatment outcomes.

The Science of Anaesthetising Large and Hazardous Wildlife

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinary team’s most critical duties. Unlike routine procedures at traditional veterinary clinics, anaesthetising a lion, rhino, or king cobra demands meticulous planning, specialised apparatus, and nerves of steel. The stakes are extraordinarily high: 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 faces genuine mortal danger. ZSL’s veterinarians have devoted years refining protocols that account for each animal’s distinctive biological makeup, physical structure, and metabolic peculiarities.

The procedure begins well ahead of the syringe penetrates flesh. Veterinarians study the individual animal’s medical history, consult with overseas experts, and establish standard physiological measurements. They position themselves strategically, guaranteeing rapid access to emergency equipment should complications arise. Once the anaesthetic takes effect, constant observation grows essential. Heart rate, blood pressure, oxygen saturation, and body temperature are monitored intensively. Recovery periods require comparably careful observation, as animals emerging from sedation can act erratically—as Guardian photographer David Levene discovered when King Arthur the cobra rose up and spat straight towards him, despite the protective glass barrier.

Preparing the Upcoming Generation of Zoo Veterinarians

The specialised knowledge required to care for endangered animals at ZSL doesn’t materialise overnight. Aspiring zoo veterinarians complete years of intensive training, starting with conventional veterinary qualifications before focusing in wild and exotic animal medicine. ZSL’s established reputation attracts skilled professionals from across the globe, many of whom complete supervised placements under the charity’s seasoned team. This practical education proves invaluable; academic study alone cannot equip a vet for the uncertainty of anaesthetising a lion or diagnosing illness in a severely threatened species where every individual matters profoundly to conservation efforts.

The veterinary team at ZSL plays a key role 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 with 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 animal welfare with sustained species preservation objectives and advancing scientific understanding of species preservation.

• Guidance from expert ZSL veterinarians with expertise in exotic animal care and urgent intervention
• Exposure to state-of-the-art diagnostic tools and pathology laboratories for applied training
• Engagement in cross-border research initiatives improving veterinary care standards for zoos
• Familiarity to diverse species requiring tailored medical approaches and conservation-focused treatment strategies