The Dragon Autopsy

What it’s like to watch a komodo dragon get dissected

Ed Yong

Try to imagine how hard it would be to skin a Komodo dragon.

It is harder than that.

The problem is that the giant lizard’s hide is not just tough and leathery, but also reinforced. Many of the scales contain a small nugget of bone, called an osteoderm, which together form a kind of pointillist body armor. Sawing through these is tough on both arms and blades.

I’m at the Royal Veterinary College, about 20 kilometers outside of central London, watching four biologists put their shoulders into the task. A Komodo dragon, which recently died in London Zoo for unexplained reasons, lies on a steel gurney in front of them. Their task, over the next three days, is to dissect it and measure all of its muscles. So, first, the skin must come off.

They’ve just started, and it is proving tougher than expected. “The knives are going to blunt really fast,” says John Hutchinson, a professor of evolutionary biomechanics, looking at the seven used blades that have already piled up on the side. Fortunately, they have spares, and the tough work of breaking into the skin eventually gives way to the more delicate job of separating it from the underlying muscles. That requires quick, dainty strokes, as if coloring in a book. The dragon-flayers settle into a rhythm, and a silence descends.

“Did you guys see the new Game of Thrones?” says Hutchinson, breaking it. “I liked it, but not enough dragons yet for me.”

* * *

The Komodo dragon is the world’s largest lizard—a giant monitor that can reach up to 3 metres from nose to tail and weigh up to 70 kilograms. Its broad-snouted face can seem, in the words of the science writer David Quammen, “as gentle and dim as a basset hound’s,” but its rugged skin, sprawling gait, and curved claws hint at the violence it is capable of. This is a predator that looks like it could take down a fully grown buffalo—and it absolutely can.

For decades, scientists believed that the dragon kills using toxic bacteria, which grow upon the strands of meat that get trapped in its teeth. When it bites a victim, the microbes flood into the wounds and cause fatal blood poisoning. But in 2009, Bryan Fry from the University of Queensland proposed the still-controversial idea that the dragon actually kills with venom. The idea is that sizeable glands in its head produce toxins that lower blood pressure, cause hemorrhaging, and prevent clotting. These symptoms are exacerbated by the dragon’s tendency to inflict huge, gaping wounds using its powerful neck and serrated teeth. Thanks to the bite, its prey bleeds heavily. Thanks to the venom, it doesn’t stop.

Komodo dragons hunt their prey on a few small Indonesian islands, including the one that gave them their name. And though formidable as individuals, they are vulnerable as a species. Fewer than 5,000 survive in the wild and their population seems to be declining, due to the usual trifecta of habitat loss, conflict with humans, and changing climate. In attempts to bolster its numbers, zoos around the world breed this magnificent creature. London Zoo has been doing so since 1927. (You may have spotted one of its current males, Raja, in the latest Bond film, Skyfall.)

Last December, the zoo’s keepers found Rinca, another male dragon named after one of the islands where they live, collapsed in his enclosure. He had been perfectly healthy until then, but he was clearly in a bad way and having trouble breathing. They spent all night trying to revive him, but it was too late. The zoo sent Rinca’s body to the Royal Veterinary College to find out why he died, so they can better care for their other animals.

The veterinarian Alex Stoll wheels him into their laboratory and, with some effort, lugs him onto a medical scanner: He still weighs a hefty 45 kilograms even though his brain, eyes, and internal organs have already been removed. “Genitalia are still there; we’ll check those out later,” Hutchinson promises. “The main thing is: Don’t touch the head. There’s danger from venom and bacteria and the teeth are very, very sharp.”

He pauses.

“Even away from the head, don’t touch it without gloves on. There’s Salmonella and other stuff.” (In 1996, a Komodo dragon in Denver zoo caused a Salmonella outbreak that affected more than 300 children.)

“Don’t touch the CT machine either.”

I decide not to touch anything at all.

Sophie Regnault and Alex Stoll prepare Rinca’s body for X-ray scanning. (Ed Yong)

The dragon is wrapped in green and red plastic sheets, like the world’s strangest Christmas present. Within the scanner, red beams dance across his head, capturing hundreds of X-ray slices. On a screen in the adjoining room, the scans appear like a moving Rorschach blot and build a ghostly model of the lizard—one that will hopefully tell Stoll why it died. His best guess is a condition called compressive cervical myelopathy, which has been reported in captive Komodos before. The animal suffers an injury that shifts some of its neck bones, causing them to press against its spinal cord, and leading to uncoordinated movements or paralysis.

Horses and large dogs get a similar condition called wobbler disease. The prognosis, sadly, is poor. Stoll will use the CT scans to look at the vertebral joints in the dragon’s neck to see if he can find sites of compression. He has also dissected the brain and will observe its neurons under a microscope: If they are swollen, that would also suggest a compression.  In captivity, the kinds of injuries that cause compression might include falling off a rock, Stoll told me. That’s what happened to a Komodo dragon that died elsewhere. It’s still not clear how Rinca died.

Regardless of the cause, Rinca’s death, though tragic, provides a rare opportunity to learn more about the biology of this spectacular animal. Hutchinson is especially interested in how it moves. He’s a scholar of animal movements, having studied the skeletons, musculature, and gaits of penguins, rhinos, salamanders, tyrannosaurs, and more.

As with many of these other species, his plan is to build a digital model of a Komodo dragon and take it for a virtual walk to see how much force its limbs generate as they push against the ground, and how much work its muscles do. “There’s reasons to think that it’s pushing the limits of what a terrestrial lizard can do,” he says. Then again, Australia was once home to an even bigger monitor lizard called Megalania—twice as long as a Komodo, around eight times as heavy, and extinct for at least 30,000 years. “We’ve scanned the skeleton of Megalania and we can use data from the Komodo to reconstruct it biomechanically.” To get that data, he needs to measure and weigh each of the Komodo’s muscles. Hence: the dissection.

Ed Yong

Hutchinson works with three others: postdoc Viv Allen, and students Sophie Regnault and Sophie Macaulay. Dressed in latex gloves, waterproof overalls, and thick rubber boots, they work in an airy hangar, flooded by sunlight on an unseasonably warm April morning. An overflowing bucket sends a stream of water into the dissecting area to wash any blood into a drain. A nearby shelf holds an array of skeletons and an secondhand copy of an old Malaysian book on Komodo internal anatomy. Medical students gawp through a window. I circle them, watching, taking photos, and being mindful of my surroundings, as stressed in the health and safety form I had to sign. (“You cannot remain blameless if a student is concussed by a swinging cow,” the form noted. Strange things happen in a veterinary school.)

“The thing I love about dissecting is that it’s kind of meditative,” says Hutchinson. “You get into the zone and once you start, you don’t want to stop. You can’t rush through it or you’ll cut your fingers. You’ve just got to go with the flow.”

It doesn’t always go that smoothly. Soon, they’re swapping their best dissection stories, like the guys from Jaws. Hutchinson plays the Hooper role. In 1997, a shipping snafu meant that a dead savannah monitor, which he was meant to dissect, sat in the back lot of a post office for two weeks. In California. In August.

By the time he got to it, “it was literally bubbling.”

Allen beats that with a Quint-worthy story. He recently flew to Louisiana with a couple of undergrads to study alligator anatomy. Jetlagged and tired, they started cutting open an animal that had been recently shot. “It was very obviously dead; it had a hole the size of my fist in its brain,” recalls Allen. “We put it down on the slab, I stuck a knife in it, and the thing walked off the table.” Reptiles, it turns out, have such slow metabolisms that their muscles can stay viable for hours after death. Hit the right nerve centre and you’ll trigger a chain reaction of muscular contractions that can send an unquestionably dead gator scurrying off a slab. “We freaked out. It just wouldn’t stop moving. We cut its head off just to make sure,” says Allen. “And then, one of the undergrads was sick in it.”

* * *

Fortunately, having died a few months ago, Rinca the Komodo dragon does not reanimate. It takes the team around three hours to remove the skin, which goes faster once they get to the point when Hutchinson can simply pull. He leans right back, while Allen separates the connective tissue.

The tail is the hardest part. There’s a ridge along the top where the osteoderms in the skin have almost fused to the underlying vertebrae. Separating the two is like sawing through bone. The scalpels start making a grating rat-a-tat-a-tat noise. Hutchinson steps back, visibly exhausted. “It’s like trying to skin a tin can,” he says. “It feels like it’s going to break the knife.” His jumpsuit is flecked with blood and there’s a little chunk of flesh stuck to his thigh.

Ed Yong

Once everything is off, it becomes clear how butch the animal is. Its exposed musculature, once coated in loose, studded skin, is now beautiful and bulging. The tail looks almost like a salmon fillet, with repeating bands of muscle and connective tissue. The biggest muscle of all—the caudofemoralis—runs from the tip of the tail to the thigh; when it contracts, its pulls the leg backward and pushes the animal upwards and forwards. Hutchinson demonstrates by tugging on it; sure enough, the leg swings backwards. “The tail is really part of the hindlimb,” he explains.

Hutchinson cuts away the caudofemoralis, and we see the dragon’s penises—both of them. Like all snakes and lizards, Komodo dragons have a hemipenis—a forked organ whose two tips emerge from separate openings.

Until they do, it can be very hard to tell what sex an animal is, which is why Rinca was initially billed as a female. The isolated caudofemoralis looks uncannily like a very long chicken breast. Carefully, Hutchinson photographs and measures it. He records its length, weight, the length of its fibers, and the angle of those fibers. All of this will tell him how fast the muscle can contract, its range of motion, and how much force it can produce. He repeats each measurement several times over, and will spend the next few days doing the same for every one of the dragon’s muscles. “This is the boring bit,” he says. I take my leave.

No part is wasted. The head, which is the only part of the animal that the dissection team didn’t touch, is going whole to Susan Evans at University College London, who studies reptile skulls. Unlike human skulls, whose movements are restricted to a yapping jaw, a lizard’s skull is exceptionally mobile, with many joints that allow the bones to shift against each other in complicated ways. This mobility, known as cranial kinesis, helps the animals to feed; Evans wants to  understand how it works and how it evolved.

Ed Yong

Like Hutchinson, she does so by building digital models of lizard skulls, to which she will now add muscles and soft tissues. These will inevitably change the spread of forces through the skull, in ways that no one currently understands. The Komodo head will be invaluable for this, especially given its size. “It’ll help us to get to grips with the anatomy on a large scale so that when we’re dissecting little tiny things, it’ll be easier,” she says.

While virtual versions of Rinca are biting and striding their way through laboratory screens, the remains of his body—skin and skeleton—are heading north to the National Museum of  Scotland, presumably to be stuffed and mounted. Even in death, the animal is glorious. Even in death, it has stories left to tell.