The Hippo with Toothache (13 page)

Since that day with Frances, I have used the topical isoflurane jelly protocol with many frogs and toads. By presenting this method of amphibian anesthesia at various scientific meetings and writing about it for veterinary medical books, I have also shared this technique widely with my colleagues. But it was Frances, our tiny poison dart frog, that made it all happen.

Mark D. Stetter received his bachelor's degree in biochemistry and chemistry, followed by a veterinary degree from the University of Illinois at Urbana–Champagne. He completed an internship in small animal medicine and surgery at the Animal Medical Center in New York and then served as staff veterinarian at the Audubon Institute in New Orleans. Dr. Stetter went on to complete a residency in zoological medicine at the Bronx Zoo/Wildlife Conservation Society, where he became associate veterinarian. He joined Disney's Animal Kingdom in 1997, when it first opened, and is currently director of veterinary services. He is board certified by the American College of Zoological Medicine, serving as president of this organization in 2006–2007. Known
among his friends and colleagues for thinking outside the box, Dr. Stetter has a special interest in medical technology and has been the first to apply advanced diagnostic and treatment techniques in a wide range of species, from frogs to elephants.

Zoo vets face unique challenges because of the vast number of species in their care, the potentially endless list of medical problems, and the great variety of conditions in which wild animals live. They must be prepared to be emergency doctors, primary caregivers, anesthesiologists, surgeons, even gerontologists. Every day is different, and many cases are one of a kind. The work can be exhausting, uncomfortable, and dangerous.

We begin our examination of every patient with what sounds like a simple process: observation. Since most wild animals have an innate fear of humans, even this first step can be hard on the doctor. In field situations, we may track the patient for hours or even days before we catch a glimpse of it. If the animal has learned to recognize the vet, we may end up hiding in vehicles, climbing trees, or sitting motionless at a distance until the animal accepts and ignores our presence. Sometimes the only option may be to join the animal in its environment: plenty of zoo vets have donned a wet suit and scuba gear and swum with their patients, even with sharks.

Once we decide it's necessary to restrain, anesthetize, or move a wild animal, we plan our approach. These procedures may carry a certain degree of risk, depending on the animal and the circumstances. Whereas an inch-long Texas dung beetle can be held gently in a pair of forceps, a 250-pound tiger requires a carefully placed anesthetic dart. Human safety is always a top priority. And even with the best planning, anything can happen.

If we don't have personal experience with the particular animal or situation—always a possibility—we review what we've done with closely related animals, read the literature, and call for advice.

Many smaller birds, reptiles, amphibians, and invertebrates can be carefully held in a net or in gloved hands. To minimize stress, it's best to lightly anesthetize them for an exam. But larger species that can bite, kick, scratch, and expel venom must be immobilized from the start. In such cases, we use a variety of potent injectable anesthetics in addition to gas anesthesia. Sometimes these drugs can be injected by hand, with the animal in a net or restraint box. More often, we inject them from a distance by a flying dart, using a lightweight CO
₂
-powered pistol or rifle.

Zoo vets tend to work long hours in difficult settings, whether it's kneeling on a concrete floor performing surgery or crawling through brambles to see a patient. Even a state-of-the-art veterinary hospital can feel like the bush when you've been working for sixteen hours every day for a week. When we work in the field, whether easily accessible or remote, all of the necessary equipment and staff must be brought to the patients. Checklists are essential, given that
something unpredictable always happens. Most of us subscribe to the rule that says plan, plan, plan … and then be flexible.

Zoo vets are known for their stamina, strong constitutions, steady hands, good aim, and healthy knees—with a bit of ego added to the mix. In this next selection of stories, these vets get physical. One works nonstop for a solid month to fly a group of dolphins to a new home. Another takes a risk while examining one of the world's largest saltwater crocodiles. Others brave logistical challenges and harsh conditions before they even have a chance to get their hands on their patients—a Bactrian camel, a herd of escaped bison, a mountain gorilla, and a forest elephant.

Lucy H. Spelman, DVM

“I'VE NEVER BEEN
successful anesthetizing a bison. Are you sure?” Over the phone, the owner of the herd sounded both demanding and doubtful. He too was a veterinarian. “The smallest animal weighs at least seven hundred kilograms and most weigh well above one thousand kilograms.” He gave me this information as if I'd never even seen a bison.

A few days earlier, I'd heard on the news that the French Army planned to shoot and kill an entire herd of escaped bison if something wasn't done soon. For the past three weeks, the animals had been wandering around the French countryside near the farm where they lived in the village of Joinville. TV crews had filmed them: the large, shaggy brown animals with huge horns appeared to be enjoying their freedom, trampling crops, eating what they liked, and charging through
small villages. It was the end of May 2004; maybe they decided the grass looked better on the other side of the fence. The authorities had tried to capture them with dogs and horses but succeeded only in running the herd around even more. Now they planned to use bullets.

I vowed not to let that happen. I felt confident that a full-scale bison recapture was achievable, especially with the help of my husband, Marc, a fire-and-rescue official who also knows how to handle scared or injured animals.

“I've used Immobilon numerous times to anesthetize rhinos, elephants, and bison, including big, excited animals,” I replied. “I've got enough of this drug for twenty animals, more than half your herd. We can do this.”

A highly potent narcotic, Immobilon is a controlled drug, and there are strict laws about its use. We have to pay for a special license to use this anesthetic on animals and are required to keep a detailed log that accounts for every drop. Only a few companies sell this drug, or a similar one; it must be imported into France from the UK; and we can only buy so much at once. But although I didn't have enough of this anesthetic for the entire herd of thirty-plus animals, I knew that bison always travel together. If we moved some, the others would follow.

With his reluctant acquiescence, I directed the owner of the bison herd to prepare for our arrival. He would need several tractor-trailers equipped with some type of lift in order to raise the anesthetized animals off the ground and transport them.

I learned that the situation had indeed become critical. As the big animals smashed down fences, they inadvertently set
hundreds of cows free as well. Farmers struggled to keep up with repairs and round up their cows. They were angry. A ranger with a rifle had managed to reduce the herd by one, shooting a bison that charged a village crowd. But when the officials proposed shooting all of the animals, the general public and animal-welfare groups reacted with outrage. In any case, this option was not only unacceptable, it was also impractical. The bison would certainly disperse at the sound of gunshots.

Finally, acting on the advice of the rangers' office and the director of the Paris Zoo, where I used to work, the veterinarian who owned the bison herd called me. He had run out of choices.

The following afternoon, Marc and I flew to eastern France. Our equipment included an unusual assortment of gear, and we were relieved when the French airport authorities cleared us through security. Most people traveling with rifles, drugs, ropes, and heavy leather straps would not get very far at Paris Charles de Gaulle International Airport!

After an hour's flight, we were met by a local government official and driven by truck to the section of countryside where the escaped bison had been grazing for the past week. Using a pair of powerful binoculars high on a hill, I watched the herd moving about peacefully in the middle of a field dotted with spring flowers—and noticeably empty of cows. Several bison drank water from a tank. Others rested lying down. The fugitives looked completely calm.

About two dozen frustrated farmers had gathered for the capture event. They regarded me warily. The veterinarian who owned the herd stood silent in the middle of the crowd.
The bison had pushed through or trampled every fence in their path, forcing the farmers to round up their cattle and lock them in barns. I could see that managing the people during this event would be half the challenge, so I began with a detailed briefing to explain a number of precautions.

“The anesthetic we use for the bison, Immobilon, is designed for large-animal anesthesia and is very dangerous to humans. It has two great advantages: potency and reversibility. A tiny amount fells a bison in less than ten minutes. Its full effect will last only an hour, but the animal will remain heavily sedated unless the drug is reversed. We carry an antidote that completely antagonizes the narcotic and can return the animal to its feet in minutes.”

I went on to explain the disadvantage: while this anesthetic is safe for hoofed animals like bison, giraffes, rhinos, and gazelles, just two drops on the skin or splattered in the eye or mouth will kill a person in less than five minutes. It is quickly absorbed and shuts down the respiratory system.

Because of this danger, I asked that everyone give us plenty of room to maneuver. Though the antidote does work on people, I emphasized that our goal was to avoid any situation in which we'd have to use it. No one should touch the darts or the animals when they first fell down under the effects of the anesthetic. Marc and I would remove the dart and pick up any that missed their targets. Helpers should avoid getting any blood from the animals on their hands. (Theoretically, the drug poses no risk to humans once it's in the bison's bloodstream, but I did not want to put this theory to the test.)

Next I explained the risks to the animal. Anesthesia in bison is risky because they tend to vomit. Moving the animals
can accentuate this tendency, since their normal reflexes are disabled by the anesthetic. The material in the rumen, the fermentation-vat portion of the stomach, includes a mixture of plant fiber, fluid, and gas. If the bison vomits under anesthesia, this material practically explodes out of the animal's mouth. It's usually impossible to clear it away from the area over the back of the tongue fast enough to prevent it from ending up in the wrong place—the opening to the airway.

I emphasized that the way to minimize this possibility was to keep the animal's head above its belly at all times. Everyone needed to follow this rule. Marc would place a sling around the bison's body and use a tractor with a pitchfork-style front-end loader to raise the animal off the ground. After looping the sling around the metal tines, Marc would ask for help in holding the bison's head up while its body was lifted into the trailer. This could take two additional people, given the size of the animals.

The farmers appeared to be listening, though several smiled or raised their eyebrows. After all, they'd been trying to capture the bison for weeks, without success. How could a woman from the city do better in one day? It also occurred to me that they might not mind if a bison or two died after all the damage the animals had caused. But I did mind.

I closed the briefing with a question: “Does anyone know if it's possible to drive a truck past the herd without disturbing them?” The farmers answered yes, no problem. We could proceed as planned.

Marc and I climbed into the truck, each armed with a loaded dart rifle and a second dart at the ready. We both wore dark green coveralls and latex rubber gloves. I had my
stethoscope in my pocket as well as the reversal drug already drawn up in a capped syringe, just in case. Each animal would receive the same dosage of Immobilon, 1.5 milliliters. Despite the stress of the situation, I felt a rush of adrenaline. I loved working with Marc, and was determined to save these roving bison.

In case one of the bison charged the truck, a ranger with a bullet rifle accompanied us as a precaution. We drove toward the herd. The animals seemed oblivious. I fired the first dart from about forty meters, into the rear end of a large female to the right of the truck. Marc got his dart off a minute later, into the shoulder of a male on the left.

Thanks to their tough hides, both bison reacted as if stung by a bee rather than a dart. They barely moved, and the herd stayed together. We reloaded and darted again. Ten minutes from the start, we had darts in four animals. They began to react, staggering and then slumping to the ground. The other bison continued to rest or eat, seemingly unperturbed.