Exotic Vetting

What Treating Wild Animals Teaches You About Their Lives

Romain Pizzi

• Publisher: William Collins
• Year: 2021
• Print ISBN: 9780008356743
• eBook ISBN: 9780008356767
• Topic: Biological Sciences
• Subtopic: Ecology
• Index: Biological Sciences

Anaesthetising a fish, x-raying a frog and hospitalising a walrus are all in a day’s work for the world’s wildest veterinarian.

Travelling from the rainforests of Sierra Leone to the jungles of Borneo, Romain Pizzi has caught, anaesthetised, diagnosed, operated on, medicated, and then released some of the world's most endangered wild animals.

From disease testing Polynesian snails to keyhole surgery in Sumatran orangutans; from endoscopy in sharks to ultrasound on a chimpanzee. Sometimes this is high tech work, such as the first robotic surgery in a tiger, or giant panda cloning attempts. Sometimes the situations are more primitive, from anaesthetising a bear with a bicycle pump, old plumbing tubes and a plank, to operating on a vulture using an old metal spoon.

In How to Operate on a Mammoth, Romain recalls his many interesting patients, while taking readers on a tour of the challenges of treating the world’s amazing spectrum of wild animal species.

1

The problem with a suicidal walrus

The walrus tries its best to commit suicide under anaesthesia by holding its breath. It has a dive reflex, allowing it to breath-hold for more than half an hour underwater. To save oxygen underwater, the heart slows down and blood vessels supplying the brain, heart and kidneys widen, to maximise blood and oxygen supply to these important organs. In other places vessels constrict, shifting blood flow away from less critical sites such as the skin, blubber and intestines. Unfortunately, when anaesthetised, all a walrus’s natural mechanisms are confused and don’t work normally. While the brain is away, not even dreaming of clams, the body thinks it is underwater. The walrus holds its breath, its heart slows, and the longer the anaesthesia the higher the risk of disaster unfolding.

Anaesthesia is controlled death. It is easy to forget this when disguised by the veneer of respectability in a modern human hospital. Despite over 150 years of anaesthesia, with millions of people anaesthetised yearly for everything from ingrown toenails to brain surgery, and wildlife vets like me anaesthetising everything from seahorses to elephants, we still don’t actually understand the precise physiological mechanisms that make anaesthetic drugs work. Why, when we give some compounds, does the brain lose consciousness, and patients don’t feel pain? It isn’t at all like sleep. Give too much and the patient dies. Anaesthetic drugs are after all toxic chemicals: poisons given in just the precise amount to keep the patient oblivious, in the narrow corridor between life and death.

Anaesthesia in the walrus is complicated by its massive weight and blubber. The thick blubber layer makes it difficult to inject into muscle. Drugs in the blubber are absorbed unreliably, and it can take ages for the walrus to become anaesthetised, making everything even more unpredictable. Its hind limbs are tiny with small muscles, so we inject drugs in the back muscles instead. The blubber makes it almost impossible to get a catheter in a vein to give injectable drugs in an emergency. A large bull can weigh one and a half tonnes. In water this is not a problem, as the weight is evenly supported by external pressure. On land, however, it is a different story. All the pressure is exerted in one direction by gravity. It’s like trying to breathe with a small car parked on your chest. Under anaesthesia, this is hardly helpful to a walrus’s wellbeing. Even with a ventilator to breathe for the unconscious animal, and using drugs to encourage a less sluggish heartbeat, walrus anaesthesia is usually nerve-racking and occasionally fatal.

Thankfully, walrus anaesthesia is not needed that often. Still, having anaesthetised over 300 wild seals, I am all too familiar with them trying to suffocate themselves under anaesthesia by holding their breath. But there are other alarming anaesthesia patients besides walruses and seals.

Anaesthesia is hours of boredom, interspersed with moments of sheer terror. My patients, if they happen to wake up inadvertently, can quickly kill me. Having an endangered Asiatic lion blink and lick her lips while I had her anaesthetised, makes one think rather quickly. She won’t be writing a letter of complaint to hospital management if she wakes up unexpectedly.

Anaesthetising the same wild animal can be completely different in disparate scenarios. Despite an intimidating appearance, white rhinos are often absurdly easy to anaesthetise in a zoo. The simplest thing is to give them a half bucket of fresh vegetables, and when they stick their head in to guzzle, to put a thin needle in one of the fine veins on the outer edge of their ear. They flick the ear once or twice as if a fly were biting them, then seem not to notice. I used to apply a local anaesthetic cream with gloves and wait 15 minutes for it to take effect, until I realised that most of them simply don’t care. I attach a long thin drip-line, so the needle isn’t pulled out, and then I will slowly inject, until, with a few big sighs, their legs crumple beneath them, and they are off to the land of oblivion. Feeding an animal while I anaesthetise it is not seen as best-practice among many anaesthetists – choking or breathing in regurgitated food are their biggest fears, and much of the human anaesthetic process is to limit the risk of this as much as possible. But a small bucket of fruit for a 3 tonne animal is like me eating half a chocolate bar. Still this horrifies some, until I explain the alternative. Would they rather have an hysterical patient running around in Accident and Emergency while you try to inject drugs into their butt-cheek? Stress hormones have a detrimental effect on the heart under anaesthesia, so this can quickly turn into an even worse scenario.

While anaesthesia for zoo rhinos is often simple and stress-free initially, this is only the getting them to sleep phase, or induction. Keeping rhinos safely asleep under anaesthesia, or maintenance, is a whole different matter. They don’t breathe well under anaesthesia, but for different reasons to walruses. Broad, flat ribs are great protection for your vital organs from another rhino charging you, but make your chest rigid. Rhinos breathe mainly with their diaphragm, and so need to move their abdomen to breathe. Lying on your belly when anaesthetised doesn’t make this easy. As anaesthesia slows down the gut’s involuntary wave-like constriction and relaxation (peristalsis), gas accumulates in puffed-up intestines, further putting pressure on the diaphragm. Again, keeping anaesthesia as short as possible is the secret to success.

Capturing wild white rhinos in South Africa, where I qualified as a vet, requires slightly more effort. Much of the time they behave like a large grey cow, only with very poor eyesight and a single horn on their nose. Rhinos don’t enjoy being darted, and can be difficult to get close to, so they are often darted from a small helicopter. As helicopter fuel is horrendously expensive, helicopters like the Robinson R22 are so lightweight they almost appear made of paper, with no doors, and an engine hardly bigger than a garden lawnmower’s. Swooping down at speed to dart a rhino from as close a distance as possible means that when things go wrong, it is the equivalent of dropping out of the sky on a moped.

Things are considerably worse outside Africa, where other rhino species are far more endangered and rare, and dense forest makes finding them very difficult. I was once asked to come up with a way to safely anaesthetise rhinos for a project that had found a tiny number of a critically endangered rhino species in a geographic region where none were supposed to exist. But they were in dense jungle, in a low-grade war zone, where the only access was via freedom fighters, or terrorists, whichever perspective you prefer. Wandering around as a foreigner in camouflage on foot with a dartgun slung over your shoulder in a rebel-held war zone for months was never going to be an easy sell to my wife.

Wildlife vets refer to a bewildering array of different things as anaesthesia. Anaesthesia is usually defined as a controlled, temporary loss of sensation or awareness induced for medical purposes, with general anaesthesia being unconsciousness and a total lack of sensation. We rarely use local anaesthesia on its own in wildlife. A dentist attempting local anaesthesia on its own in a lion would be a one-patient wonder. In many cases we simply want to be able to handle, take a blood sample, or even just put an animal in a transport crate, and don’t need the same depth of anaesthesia to block pain as for an operation. This is immobilisation, rather than anaesthesia, although the terms are often interchanged. Usually, when moving animals such as rhinos, we actually want them to be standing, so a lightly sedated rhino can be walked, although stumbling, with guiding ropes into a truck without the risks that come with full anaesthesia. This also has the benefit of the rhino doing the hard work for us, rather than needing a crane to lift it.

Standing sedation is the secret to safe capture of one of the least favourite anaesthetic patients of any wildlife vet: giraffes. Although their necks can be more than 2 metres long, they still only have seven neck bones, the same as most mammals. They also have a surprisingly thin skull. An anaesthetised giraffe keeling over and hitting the ground risks fatally breaking its neck. Better if we can dart the giraffe, then rush over before it falls down, and partly reverse the anaesthetic drugs. With some leg ropes and a blindfold the giraffe is dozy, but can be safely walked into a transport truck.

The dartgun

In July 1850, the Times newspaper reported the first successful anaesthesia in a wild animal. A cheetah at London Zoo had managed to break its leg. A sponge of chloroform on a long stick was held to its face until it become unconscious, and a successful amputation of its mangled leg was carried out under chloroform anaesthesia. But a chloroform-soaked sponge, even on a stick, is useless for lions or elephants running around the African savanna or orangutans swinging through the Bornean rainforest.

Enter the dartgun. While its invention may seem obvious, it wasn’t so at the time. There were several insurmountable problems. Syringes, even after World War II, were made of glass, so hardly suitable for being shot out of a gun. Early human anaesthetic drugs needed injection via a vein, which was impossible with a dart, and most needed large volumes to be given.

First attempts at remote anaesthesia differed little from how South African bushmen and South Americans hunted wildlife with poison-coated arrows. Animals were shot with arrows coated with drugs such as curare and strychnine that their muscles had to dissolve and absorb slowly. One early attempt was actually a metal drill bit, the grooves filled with gallamine and glucose, shot into white-tailed deer with a carbon dioxide gun. Curare was used by native South Americans in blowpipe darts to kill animals for thousands of years. Gallamine was similar to curare, and both were terrible for anaesthesia. They paralysed muscles, so an animal couldn’t move but was totally awake and could still feel pain normally. A tiny bit too much and it also paralysed the breathing muscles, with the patient suffocating. Another early design, powered by thick elastic bands, was lovingly named the bazooka, which perhaps wasn’t the greatest endorsement.

Veterinarians have always proved to be extremely inventive. We have vet John Dunlop to thank for the pneumatic tyres we take for granted on our cars and bicycles. New Zealand vet Colin Murdoch was even more creative. Aged only 10 years, he made his own gunpowder, and a few years later his own homemade gun. Working after World War II, his most remarkable invention was the disposable plastic hypodermic syringe. He knew that despite boiling for sterilisation, glass syringes frequently spread infections between patients. The New Zealand Department of Health wasn’t convinced of the merits of the plastic syringe and so he couldn’t progress its development for several years, but it paved the way for another of his 46 other patented inventions.

Faced with the difficulties of catching Himalayan tahr, a large hairy wild goat introduced to New Zealand 50 years earlier for sport hunting, Murdoch invented the first dartgun. This would completely revolutionise wildlife veterinary work, particularly in Africa, with its many large dangerous wildlife species. However, there were still few suitable drugs. Murdoch started testing his dartgun using curare, which unfortunately killed many of the animals. Over the next two decades, a host of different companies came up with their own systems. Some used blank firearm cartridges, and without care the metal syringes could fatally shoot straight through smaller animals. Others used carbon dioxide, or a foot pump. Dart syringes also had different designs and mechanisms for injecting the drugs. Some were powered by butane or compressed air, while others used springs or bicarbonate-driven reactions caused by a tumbling eccentric weight.

In the late 1950s, the first successful dartgun captures of African game animals were carried out, on the kob, a beautiful orange-brown antelope with spiral horns, using a muscle paralysing drug similar to curare called succinylcholine. While this worked, better more potent drugs were clearly needed. The man who made these first captures and almost single-handedly started modern African game capture was Antonie ‘Toni’ Harthoorn. A tall and lanky Sandhurst-trained officer and commando during World War II, he graduated from the Royal Veterinary College in London, before ending up in East Africa. He started trialling strong opioids, drugs derived from morphine or other opium poppy compounds, in as many wildlife species as he could. He had plenty of opportunity, when rescuing wildlife stranded by the new Kariba Dam on the Zambezi river. In the early 1960s, he invented a breakthrough drug combination called M99. It contained etorphine, an opioid that was a thousand times as potent as morphine. Two to three millilitres was enough to anaesthetise an adult bull elephant. Etorphine is still one of the mainstays of anaesthesia in African wildlife today. It was originally discovered by Edinburgh researchers studying new anti-inflammatory medicines, when someone stirred the cups of tea with a glass lab rod that, unbeknown to them, had tiny traces of etorphine on it. Their shoddy hygiene almost killed them, but helped discover the drug for anaesthetising elephants in Africa. Etorphine was even investigated by British American Tobacco, who hoped it might create an additional addictive craving for cigarettes.

The benefit of such a concentrated drug was dramatic. When Harthoorn needed to move 100 white rhinos from the Hluhluwe-Imfolozi game park in South Africa, he had started first with morphine combinations for anaesthesia. The volumes were huge, requiring big 20-millilitre darts with considerable impact force. Ian Player, the park warden, describes wounds so large that he was forced to insert almost his whole arm into the depths of the animals to clean them out. Morphine was quickly abandoned for the slightly more potent opioid diethylthiambutene, but the huge volumes and wounds remained a problem until etorphine arrived.

Harthoorn went on to run a wildlife orphanage, and with his vet wife Sue Hart treated George Adamson’s lions, made famous by the film Born Free. He inspired the TV show Daktari and the film Clarence the Cross-Eyed Lion, although he shunned the limelight himself. Abruptly losing his job at Nairobi University following Kenyan independence in 1963, he moved to South Africa where he continued pioneering wildlife capture, anaesthesia and medicine, some of which has still hardly changed. He wrote scientific papers and a 416-page book on the chemical capture of wildlife, which I still treasure on my bookshelf. Then, in a bizarre twist after retiring, he became a homeopath. The scientific pioneer of wildlife veterinary anaesthesia changed career to a human alternative medicine with no scientific basis at all. And he was still happily practising while I was studying at veterinary school.

Etorphine worked wonderfully in large herbivores, but not for carnivores. In South Africa we used phencyclidine, a human anaesthetic with the street drug name of ‘Angel dust’, to anaesthetise lions. For a while some North American wildlife vets used this on mountain lions as well. A long-retired colleague described how, in desperation, he once smuggled Angel dust in an aftershave bottle across Europe to anaesthetise his safari park lions. It can’t have been pleasant. It took ages to work, lions were very twitchy, vomited and sometimes had seizures. It was thankfully replaced by the new human anaesthetic drug ketamine during the Vietnam War, when the American army also switched away from phencyclidine. Ketamine remains one of our main wildlife anaesthetic drugs today.

It seems logical that most cat species would metabolise drugs similarly; however, that isn’t the case. Bizarrely, tigers don’t tolerate the same anaesthetic drug dosages that lions do, despite being a similar size and are more prone to seizures under anaesthesia. Another group that reacts to anaesthetics very differently is bears. The first time I anaesthetised rescued sun bears in Cambodia a decade ago to transport them, I used drugs that work well in brown bears, and even moon bears, which live in the same region. But the sun bears’ bodies drank the drugs up, and I had to use huge doses to get them asleep. They stayed anaesthetised for hours, and I had to stop the trucks every 15 minutes to wet the bears down so that they didn’t overheat. Thankfully they were fine, but I never used that combination again. Even giant pandas react to medications very differently, particularly opioid drugs. Tramadol is a common painkiller for people and animals. At worst, side effects in humans are nausea and feeling slightly groggy. But in large animals, the consequences can be more far-reaching. A colleague once gave an arthritic giant panda a single low dose of tramadol, and was horrified to find she slept non-stop for almost four days without eating or drinking.

Concentrated drugs via the flying syringe, as dartguns were originally called, still have limitations. Darting a black wildebeest bull should be easy. Males are territorial during breeding season, unlike their crazy blue cousins. In good bushveld, you can see a male every few hundred metres just standing in his little area, keeping an eye out for passing females, or a neighbouring male drifting into his area to be chased off. You can drive to within 50 metres of a bull, if you approach slowly and obliquely. Approaching head-on is a guaranteed way to scare off any animal. You can get a long but reasonable shot with a well-maintained dartgun, but not if there are plains zebra around. These wandering pyjama-donkeys are far more suspicious, and before you can ever get close enough to be within dartgun range, with a loud bark from the stallion they all stampede off, triggering the wildebeest bull to do the same. You can waste a whole day staring at the jumble of bouncing striped bums running away, never able to take even a single shot at your wildebeest bull. Yet a zebra’s flight zone, the distance it lets you approach before galloping off, is modest compared to some animals. Gemsbok are possibly the most beautiful of all antelope. But living in the Namib desert they can spot you kilometres away. Sometimes the only sight you can glimpse of a small herd is a tiny puff of dust on the horizon, making them impossible to reach with a dartgun from your Land Rover.

While it’s easier to use a dartgun in a zoo, there is still a risk of injury, and at the least it is unpleasant and painful for the patient. It is often not much fun for the vet, either. I remember early in my career having to dart a gorilla. She knew what was going to happen and quivered in the corner, trying to hide herself in straw and crying. It was nerve-racking trying to dart her, but also distressing. Over the years I have seen all sorts of mishaps, from a pregnant antelope being darted directly into the brain, to broken bones and unfortunate deaths from unlucky shots.

Zoos now design enclosures with squeeze cages for us to safely inject patients by hand, or even better, train animals for hand injection. An adult tiger trained to calmly accept an anaesthetic injection is better for both patient and vet. Without surging adrenaline, anaesthetic onset is rapid, and much safer. This is now common for everything from chimpanzees to giant pandas.

There are other ways to make anaesthesia less stressful for our patients. We can sometimes anaesthetise animals like bears by putting drugs in their food. Carfentanil is an opioid that is ten thousand times the potency of morphine, even more potent than etorphine. Mixing it with a tablespoon of honey means bears will happily anaesthetise themselves. Even better, they seem happy to take it again in future, making repeated anaesthetics easy, rather than getting the animal stressed and wary. It even works in the most suspicious of zoo anaesthesia patients: chimpanzees.

Potent opioids would appear useless outside elephant anaesthesia, as even a tiny dose could be fatal to humans. In October 2002, when Chechen terrorists occupied a theatre in Moscow and took 900 people hostage, the Russian authorities pumped a chemical agent into the ventilation system to incapacitate the terrorists. Sadly, more than a hundred hostages also died. While the Russian government never divulged what it used, later analysis of clothing at the Porton Down military research centre demonstrated that the chemical cocktail contained carfentanil.

Carfentanil was also used to cut heroin, with the predictable result of accidental deaths due to drugs being more potent than addicts had expected. These problems have led to opioids such as etorphine and carfentanil, which we so heavily rely on in wildlife anaesthesia, becoming very restricted. It is now impossible to import them for genuine wildlife work in much of the world. In some cases, we now have to use less safe and effective drug combinations than we were using half a century ago. I recently had my first giraffe anaesthesia death in two decades, because I couldn’t get etorphine imported into the country I was working in, which was very sad and extremely frustrating.

Oral anaesthetics have also been used in wild birds. Sandhill cranes have been caught by mixing alpha-chloralose, a barbiturate, with corn and then catching them by hand when heavily sedated and unable to fly. It takes cranes 24 hours to recover, during which they have difficulty regulating their body temperature. It is essential to prevent them from overheating or becoming cold, both of which would be fatal. Alpha-chloralose is actually mainly marketed as an avicide – a poison to kill birds eating farm crops – highlighting the fine line anaesthesia treads between life and death.

There is the real danger that birds will gobble the anaesthetic corn and fly away before the half an hour it takes to have effect, so it is best offered late afternoon. Then if the cranes do fly away, they will likely roost nearby. Many birds have a crop, a dila...

Table of contents

• Cover
• Title Page
• Copyright
• Praise for Romain Pizzi
• Dedication
• Contents
• About This Book
• Introduction
• 1 The problem with a suicidal walrus
• 2 Catching crocodiles with shoelaces
• 3 When a bird in the hand is not better
• 4 How to squeeze a porcupine, and look an owl in the eye
• 5 Getting blood from a stone is easier than from a killer
• 6 Why deer don’t die of sickle-cell anaemia
• 7 Lies, damn lies, and test results
• 8 Turtle migraines and the six-fingered woodpecker
• 9 How sidewinder missiles help a black rhino
• 10 Surgery and the secret police
• 11 Hippopotamus dentistry with an angle grinder
• 12 Manatee junk food
• 13 A spoonful of ants makes the medicine go down
• 14 To breed or not to breed?
• 15 Winnie-the-Pooh was shot
• 16 Die free
• 17 Why?
• Picture Section
• Acknowledgements
• Index
• About the Author
• About the Publisher