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 documented a year following the charity’s elite veterinary team, capturing the remarkable difficulties of caring for some of the world’s rarest and most vulnerable animals. From anaesthetising a king cobra that responded to anaesthetic with a venomous spray to examining an Asiatic lion’s unusually narrow ear canal, the vets, nurses and specialists working across ZSL’s London and Whipsnade zoos navigate medical emergencies that few other professionals ever face. 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 represent a unique form of veterinary knowledge—one that has pioneered animal welfare practices for 200 years.

A Year of Remarkable Clinical Pressures

David Levene’s year-long photo documentation revealed the unpredictable nature of zoo animal medicine. On his second visit, the photographer encountered Bhanu, an Asiatic lion suffering from persistent recurring ear infections that had resulted in an exceptionally constricted ear canal. The condition necessitated a general anaesthetic—always a final option in zoo medicine—so the veterinary team could perform a comprehensive assessment. Whilst Bhanu was under sedation, the vets took the chance to perform detailed health assessments, encompassing careful examination of his teeth, which are essential for a meat-eater’s wellbeing and survival in captivity.

Perhaps the most dramatic 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 be fatal to an elephant, yet the ZSL team handles such exceptionally perilous patients with practiced care and unwavering professionalism.

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

The Experts Responsible for Keeping Endangered Species Alive

The animal health team at ZSL represents one of Britain’s most highly specialised workforces. With five fully qualified veterinarians, six nursing professionals, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist, the charity operates what most British zoos can provide: a full in-house medical facility. This multidisciplinary model enables the team to manage the complicated medical requirements of creatures extending from dormice to rhinoceroses. Each specialist provides crucial expertise, whether identifying unusual parasitic infections, studying genetic material or conducting complex surgical procedures on animals worth millions to worldwide conservation efforts.

The difficulties these professionals face are distinctly uncommon. Relocating a sedated rhino necessitates thorough planning and specialist equipment. Sedating a dormouse calls for exact pharmaceutical measurement for an animal tipping the scales at mere grams. Managing the care of a venomous snake requires comprehending its behaviour and physiology in ways that relatively few veterinarians come across. The ZSL unit has to regularly innovate, utilising years of accumulated knowledge whilst adapting their methods to individual animals. Their work extends far beyond regular assessments; they are stewards of some of the Earth’s endangered species, where a single animal’s survival can bear major preservation implications.

From Early Pioneers to Present-day Medicine

ZSL’s dedication to animal wellbeing dates back 200 years. The journals of Charles Spooner, the zoo’s original “medical attendant,” offer some of the earliest written accounts of animal medical care in Britain. Spooner treated a young lion cub named Nelson affected by mange infection, teething troubles and a life-threatening ulcer on his jaw. Through careful treatment—opening the ulcer and administering daily doses of zinc sulphate—Spooner rescued the cub’s life, creating a record of innovative, compassionate animal medicine that continues today.

This historical foundation has informed modern ZSL veterinary practice. The principles Spooner pioneered—precise scrutiny, creative problem-solving and unwavering dedication to individual animals—remain fundamental to the team’s approach. Over two centuries, ZSL vets have regularly extended boundaries in animal health and welfare, producing research and creating techniques now embraced internationally. As the zoo commemorates its bicentenary, its veterinary team stands as a living testament to two hundred years of innovative leadership in exotic animal medicine.

Precision Surgery on the Planet’s Rarest Animals

Every surgical procedure undertaken at ZSL represents a calculated risk with far-reaching significant consequences. When a veterinarian operates on an endangered animal, they are not simply caring for a single creature—they are protecting an entire population whose continued existence could rely 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, collaborative research with overseas specialists, and an deep knowledge of the specific animal’s medical history and unique characteristics.

The intricacy grows significantly when working with creatures whose bodily composition varies considerably from tame species. A rhino’s cardiovascular system reacts unpredictably to sedative drugs. A snake’s metabolic processes metabolises anaesthetic agents at rates that exceed conventional guidelines. A dormouse’s tiny body leaves almost no room for error in drug dosing. The ZSL veterinary staff has developed bespoke methods and surveillance equipment to overcome these obstacles, often developing novel methods that subsequently become established protocol across zoological organisations worldwide.

• Anaesthetising dormice requires accurate micrograms of carefully calculated pharmaceutical solutions.
• King cobras demand secure containment protocols during recovery from sedation procedures.
• Rhino relocations necessitate specialised apparatus and integrated multi-agency operations.
• Dental examinations on carnivores reveal key markers of general wellbeing.
• Post-operative monitoring involves continuous surveillance by dedicated veterinary nursing staff.

The Affectionate Relationship Between Animal Carers and Animals

Behind every successful medical procedure lies a profound relationship between keeper and animal. Zookeepers like Tara Humphrey devote extensive time observing their charges, identifying subtle behavioural shifts that indicate illness or distress. When Bhanu the Asiatic lion was anaesthetised for his ear check, Humphrey took the uncommon chance for tactile contact, embracing the impressive animal whilst he lay asleep. These bonds go beyond mere emotion; they embody the thorough understanding that allows keepers to deliver vital details to veterinarians, ultimately enhancing diagnostic accuracy and therapeutic results.

The Science of Anaesthetising Big and Potentially Dangerous Animals

Administering anaesthesia to the zoo’s most formidable residents represents one of the veterinarians’ most critical responsibilities. Unlike routine procedures at conventional animal hospitals, anaesthetising a lion, rhino, or king cobra demands careful preparation, specialist equipment, 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 collapse; give insufficient medication to a venomous snake and the keeper encounters genuine mortal danger. ZSL’s veterinarians have devoted years developing procedures that account for each species’ distinctive biological makeup, physical structure, and metabolic peculiarities.

The process begins well ahead of the syringe penetrates flesh. Veterinarians study the specific creature’s clinical background, liaise with overseas experts, and determine standard physiological measurements. They arrange themselves with precision, guaranteeing rapid access to emergency equipment in case problems develop. Once the sedative begins working, constant observation becomes paramount. Pulse, arterial tension, blood oxygen levels, and body temperature are tracked relentlessly. Recovery periods require equally vigilant observation, as animals coming out of anaesthesia 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.

Preparing the Upcoming Generation of Zoo Veterinarians

The specialised knowledge required to care for endangered animals at ZSL does not emerge overnight. Prospective zoo veterinarians complete extended periods of intensive training, beginning with standard veterinary qualifications before focusing in exotic and wild animal medicine. ZSL’s established reputation attracts talented professionals from throughout the globe, many of whom complete supervised placements under the charity’s seasoned team. This direct education proves invaluable; theoretical learning alone cannot prepare a vet for the unpredictability of anaesthetising a lion or diagnosing illness in a at-risk species where each animal matters profoundly to conservation efforts.

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 standard wellness examinations to emergency interventions—whilst working with specialists in pathology, microbiology, and molecular diagnostics. This multidisciplinary environment fosters innovation in animal healthcare and ensures that emerging practitioners understand the wider implications of zoo medicine: reconciling immediate creature wellbeing with long-term conservation goals and advancing scientific understanding of species preservation.

• Mentorship from seasoned ZSL veterinarians with expertise in exotic animal care and emergency response
• Access to state-of-the-art diagnostic equipment and laboratory facilities for hands-on learning
• Engagement in collaborative research projects enhancing standards in zoo veterinary medicine
• Exposure to various animal species needing customised treatment methods and conservation-focused treatment strategies