silverguide.site –

• Some images may be upsetting to young audiences

How do you shift a sedated rhino? Can a dormouse be drugged? What happens to a lion with an unusually small ear canal? How does the world’s longest venomous snake respond to treatment?

Not easily, was the answer to the final question, as Guardian photographer David Levene discovered during a year following intricate veterinary operations on some of the world’s most endangered animals.

When Levene took a photograph of a king cobra snake just after it had received an anaesthetic, the animal affectionately known as King Arthur gave him its own version of the hairdryer treatment. “I was the first person he saw after he’d been jabbed in the tail and he reared up and opened his mouth and started spitting at me. I was behind glass but I told him, ‘It wasn’t me!’” says Levene.

Large, dangerous, small, incredibly rare – the exotic and native animals kept by the Zoological Society of London (ZSL) at its zoos in London and Whipsnade pose very different challenges for the veterinary team who work for the charity.

“On the second day of the project, I found myself face-to-face with a lion – it was definitely a baptism of fire,” says Levene.

The Asiatic lion, Bhanu, was suffering chronic recurrent ear infections, which caused him to have an unusually narrow ear canal. He required a general anaesthetic to be examined fully. A “GA” is always a last resort, but Bhanu was fine. While he was under, the vets performed as many checks as they could, including inspecting his teeth – which are, of course, crucial for a carnivore’s health and happiness.

The vets who treat the animals at Whipsnade and London are a special team. Only a handful of British zoos employ their own in-house veterinarians. ZSL, which celebrates its 200th birthday this spring, has five vets, six nurses, a pathologist, a pathology technician, a molecular diagnostician and a microbiologist.

Over its 200 years, ZSL vets have played pioneering roles in animal health and welfare. The journals of the zoo’s first “medical attendant”, Charles Spooner, provide some of the earliest written evidence of veterinary care. A young lion cub called Nelson was suffering from mange, teething troubles and an ulcer on his lower jaw, which is often fatal for lion cubs. Spooner lanced the ulcer and administered a daily solution of sulphate of zinc, and the cub recovered.

Herpetologist Joan Beauchamp Procter, who was made the first female curator of reptiles and amphibians in 1923, transformed their care with an innovative reptile house. Oliver Graham-Jones, Britain’s first dedicated zoo vet, was appointed in 1951 and invented the handheld dart gun, allowing anaesthetics to be safely administered from a distance.

Levene’s year at the zoos began when he visited London to take photos of an art exhibition based on animal poo. Close to the artist’s studio was the veterinary hospital. “Instantly I thought, ‘Wow, I need to see what’s inside,’” says Levene, who wanted to be a vet as a boy. Months of negotiations later, he was given unprecedented access during 2025.

It takes more than a dozen vets, nurses and keepers to haul a sedated rhino into place for an operation – anaesthetised animals do not always fall asleep in a convenient location. Security staff had to also be on high alert when Kiburi, the 177kg, 21-year-old patriarch of London zoo’s western lowland gorilla troop, was sedated and taken for a CT scan and full health check.

All operations require precision, but the daintiest of procedures are particularly taxing. The dormouse pictured under anaesthetic is part of a captive population bred by the zoo for UK conservation and reintroduction programmes, with the severely declining species under threat. Levene watched as nine mice were weighed “and then put under anaesthetic with gas delivered by these tiny little face masks” so their health and growth could be meticulously checked.

Although Levene was drawn to the drama of treating big, charismatic animals, his favourite picture is another image of an intricate procedure: four medical staff tending to a mountain chicken frog – a small specimen that can grow into a huge 1kg amphibian. Just 21 of the critically endangered frogs were found left in the wild during a 2023 census; ZSL is now playing a key role in the Mountain Chicken Recovery Programme, working out its wild challenges (chiefly amphibian chytridiomycosis, caused by a deadly microscopic fungus) while breeding it in captivity to increase their numbers.

This particular mountain chicken frog was suffering from gallstones, so vets operated on its gallbladder. “I love the intent on their faces,” says Levene. “It just shows the level of care and attention that goes into creatures large and small. They are all equal in the vets’ eyes.”

During his year behind the scenes, Levene was struck by “the passion and the professionalism that goes into the care of the animals. I was also taken with the steely focus that came over people. The vets, nurses and keepers were really lighthearted. There was lots of joking, but as soon as we were in that surgical setting, they were laser-focused. They were so concerned with the welfare of the animal that it was almost uncomfortable for the observer, because you didn’t want to get in the way.”

There was a delicate balance between Levene’s need for up-close access alongside the urgency of emergency procedures and the safety requirements of working with dangerous wild animals. “I was lucky that they trusted me, to allow me to be that close,” he says of the moment he captured the vets clustered around Bhanu the lion’s mouth, one vet using a phone – covered in big cat stickers, naturally – to better illuminate its gums.

While the vets sought to maintain their detachment while treating animal patients, the keepers can’t avoid a more intimate relationship. “The keepers are living with the animals every day and get to know them really well,” says Levene. “They are still very professional, but a procedure is a much more emotional thing for them. When a dangerous animal is under anaesthetic, they are all over them – taking the opportunity to cuddle these animals, smell them.”

After taking 50,000 photos of multiple procedures over the year, Levene felt the wonder of proximity to these incredible animals, and the dedication of the professionals who care for them. The texture of a lion’s tongue; the weight of its paw – these are unforgettable encounters. At one point, Levene was persuaded to put down his camera and gently hold a sedated lion’s paw. How was it? “It was biiiiig,” he says. “It was a big unit of a paw. A good two hands-worth.”

* * *

‘It’s a huge undertaking to anaesthetise a rhino’: the animals ‘going under’

Inside the veterinary hospital at London zoo, each day begins with a meeting, writes David Levene, shared by video link with the team at Whipsnade, to run through the schedule of treatments and procedures for the day ahead.

At 8am sharp, all the Wildlife Health Services team gather in the coffee room to run through the tasks for the day ahead, typically including a mix of inpatient procedures for more serious health concerns, plus inspections and medication for animals with minor ailments. Treatments for more serious conditions, or to work safely with dangerous animals, require a general anaesthetic (GA). These can sometimes be managed in the treatment room with a vet and a nurse. More complex procedures might require multiple in-house vets, external specialist teams, three or four nurses and a supporting cast of zookeepers and other staff, often taking place within the animal enclosures rather than the vet hospital.

Anaesthesia is routinely used for welfare and safety reasons, and to reduce stress levels placed on animals. For animals that have undergone training to teach them to offer their tail to the nurse, anaesthetising can be a straightforward process with a simple injection through a protected opening to the animal enclosure. Very large, dangerous or downright obstinate patients might require a different tack, such as a dart fired from an air rifle.

After a procedure where the animal is sedated, a “reversal” drug is sometimes used to gently bring them back to consciousness.

* * *

‘I’ve had to upheave my life to do this!’ A veterinary resident’s first six months

Harriet Woodhall is the new veterinary resident at ZSL, a three-year training programme designed to offer a springboard to the lucky few candidates who have chosen zoological care as their veterinary specialism.

A large proportion of trainees would say that they’d love to become a zoo vet, but only a handful manage it.

“I’ve had to upheave my life, and my partner’s life!” Woodhall says. “If you’re not willing to make the sacrifices in pay and time off and life outside of work, then I can understand why people give it up.”

Like many other vets before her, Woodhall cut her teeth working almost exclusively with domestic cats and dogs in small-animal practice – where about 80% of UK vets work – before moving into exotics such as reptiles and amphibians. This foundational work is essential: traditional practice builds the surgical and clinical skills that can later be applied to the dizzying numbers of species and physiologies found in zoo settings, worlds away from the familiar mammals found in homes around the world.

As one ZSL veterinarian explained: “It’s very rare that someone will just graduate and go straight into a zoo. You need to be spaying pets, doing routine surgeries, caesareans, intestinal surgery, so you’ve got good foundational knowledge and skills.”

Woodhall knew from a young age that she wanted to work in zoos. “Whipsnade wasn’t our closest zoo, but it was the one that I would go to. I remember going a lot as a kid and seeing the changes over the years. I even remember the days when elephants were walking around the zoo and they had sea lions and all sorts. Going there inspired me to go into this field.”

* * *

‘These are rare animals. We want to learn more about them’: inside the pathology department

Simon Spiro is the UK’s only full-time zoo pathologist, “possibly the only one in Europe”, he muses. The pathology department he runs plays a vital role within ZSL and beyond, helping zoological science to achieve a deeper understanding of all the varied species held within the zoo’s collections.

Spiro is responsible for assigning a cause of death to every animal that dies at London and Whipsnade zoos, both as a legislative necessity as well as for general transparency. It’s “part of how we’re regulated and monitored, so people can be confident that animals aren’t dying for horrible reasons that no one would ever find out about”.

But his analyses also feed back to the team of vets working day in, day out to care for the zoos’ animals.

“The vets are diagnosing animals, they’re treating animals. They need to know if they’re correct. It’s one thing to make a diagnosis, and we may work on the presumption that an animal has cancer, for instance, but until you have the pathology, until you have the results of the postmortem, you can’t really know for sure. So that lets us mark our own homework, as it were. It lets us know what we’ve got right, but then it also lets us know what we’ve got wrong.”

The work that Spiro and his team carry out in the pathology and molecular diagnostics labs also contributes to a multitude of research programmes and initiatives, helping to monitor the spread of zoonotic diseases, develop thinking about animal welfare, and inform governmental policy and decision-making.

“You can’t do all the investigations you might want to do on an animal while it’s alive. These are rare animals. There’s not much we know about them and we want to learn more about their anatomy, their physiology.

“ZSL is a conservation organisation, and conservation is fundamentally about stopping animals from dying, and if you don’t understand why they’re dying there’s no way you can do that.”

* * *

‘The zoo was never originally intended to be a place of entertainment’: the importance of science and conservation

London zoo isn’t just a zoo. It plays a major part in a global network of animal science and conservation. The ZSL, of which London and Whipsnade zoos are part, was founded 200 years ago by Sir Thomas Stamford Raffles “for the advancement of zoology and animal physiology”. That central ethos holds true to this day.

“The zoo was started as a scientific organisation to study animals,” says ZSL’s head vet, Amanda Guthrie. “It wasn’t originally intended to be open to the public. It wasn’t for quite a few years until people realised that they probably needed money to operate the zoo! Bringing visitors in would allow that. But the zoo was never intended to be a place of entertainment. It was primarily for the scientific study of animals and it stayed that way.”

The ways in which ZSL contributes to the advancement of scientific understanding and animal conservation are myriad, encompassing outreach, education, research, protection, preservation and even reintroduction of endangered species. It works with multiple partner organisations, domestic and international, to further knowledge and expertise about animal health and husbandry. It runs a wildlife disease risk analysis initiative with Natural England and contributes data to the Zoological Information Management System database that charts the health and welfare of thousands of species around the globe.

“We follow animals in the zoo from birth until death, we keep detailed records, and we do a full postmortem investigation when they die,” says Guthrie. “We understand every single aspect of their life. We get to learn new stuff every day, so the fulfilling and rewarding part of this job is to contribute to the science and knowledge that, in 30 years, someone can refer back to what we’ve discovered or described, and it’ll benefit those animals in the future.”