16

Never Work on a Species That Is Smarter than You Are

I adore reptiles, and I always have—ever since my childhood, when I encountered small lizards in the backyard of our suburban house in Brisbane, in subtropical Australia. And I respect reptiles. They are sophisticated and elegant animals, pursuing mysterious lives. Their ecological footprint is vastly lower than that of energy-squandering warm-blooded mammals and birds. So in a very real sense, I’m a reptile zealot. I have devoted years of effort into public relations for reptiles, especially snakes, to convince the general public that scaly creatures have real value.

But intelligence? It pains me to admit it, but by and large, reptiles are not the sharpest tools in the toolshed. Brains are expensive, chewing up more energy per gram than any other type of bodily tissue. So for an energy miser like a reptile, investing resources into cognitive ability is unlikely to be worthwhile. For the average lizard, being smarter doesn’t pay off in the cold hard calculus of natural selection. I don’t doubt that there are some cold-blooded geniuses out there … for example, recent research on lizards has revealed fascinating complexities in social systems and some spectacular examples of cognitive gymnastics. But if you’re looking for Animal Einsteins, you probably won’t spend much time in the reptile house of the local zoo.

To be brutally frank, my adoration for reptiles is based on many characteristics of these fantastic beasts … but problem-solving ability isn’t high on that list. Of course, I may be wrong. Humans tend to rate other creatures as intelligent when we look into their eyes and perceive some subtle cues that hint at mental activity going on in their brains. And inconveniently, most lizards and snakes are so small that peering into their eyes requires more visual acuity than I can muster.

But a few species of reptiles are big enough for a human being to peer into their eyes. And fortunately for me, Australia is home to some of the biggest lizards on planet Earth. The really outsized species all belong to a single family—the Varanidae—which are known as monitor lizards in most parts of the world but are called goannas in the Land Down Under. Some of these animals are genuinely huge, especially the Komodo Dragon (Varanus komodoensis), which evolved in Australia but is now found only on a few small islands to the north. A large male Komodo can weigh more than 90 kg (200 lb) and can take down prey as large as adult water buffalos. Anyone who believes in the innate superiority of the human race over lowly cold-blooded creatures should take a trip to the island of Komodo, where lizards are in charge of the ecosystem. Komodo Dragons are more than big enough for a person to look them in the eye. And when you do, you realize that the lizard regards you as a potential dinner rather than as a threat to its existence.

The varanid lizards that are still found in Australia are smaller, with the Komodo Dragon’s close relative, the Lace Monitor (Varanus varius), weighing in at up to 14 kg (30 lb). But that’s still a lot of lizard, especially when it stands up on its hind legs, hisses like a steam train, and lunges at you. Goannamosity incarnate. More than 2 m (6 ft) long, with massive claws, serrated teeth, and a muscular tail that can be thrashed around as an additional weapon. I well remember the first big Lace Monitor I ever caught, when I was about 10 years old. Aware of the damage that could be inflicted by those teeth and claws, I leapt upon the lizard with one hand around its neck and the other on its hindquarters, thereby taking those formidable weapons out of play. But I didn’t have enough hands to control the tail as well, and a mighty slash of the tail across my face left me with a profusely bleeding nose for the next 30 minutes. By the time I arrived home, my shirt was soaked in blood; my mother thought I’d been hit by a car.

But brute strength isn’t the only ammunition in the goanna’s arsenal. They are smart. There’s something special in the way that a goanna looks at you. They seem to feel that the biblical injunction about humans having dominion over all the wild animals of the earth should have been followed by an asterisk that directs you to a footnote saying except varanid lizards. It’s difficult to feel superior when you come back to your tent after a hike to find the side of the tent slashed open, a steamy pile of lizard poo on your sleeping bag, and a giant lizard slumbering on a tree limb several meters above the remains of your camping gear. Especially when the swollen belly of that lizard contains the steak that you had brought along for the night’s dinner.

Any herpetologically obsessed child has a few misadventures while they learn how to catch reptiles. That’s especially true in Australia, where most of the snakes are venomous. But despite many near misses from tackling deadly snakes, only one youthful encounter inflicted a wound still evident on my now-elderly body: a long scar on my forearm. And that wound was donated by a goanna, not a snake. I had climbed a eucalypt tree in pursuit of a huge Lace Monitor. Perhaps surprisingly, I had managed to seize the lizard without losing any blood—but then was faced with the problem of getting back down. Climbing required at least one hand, meaning that I could restrain the goanna only around the neck. And as soon as I released its tail base, those powerful hindlimbs swung around and the lizard sunk its hind claws into the meat of my forearm. By the time I reached the ground, that laceration was down to the bone.

Okay, you might think, a goanna can defeat a child—but surely an adult human being can stand up to any lizard? I can only wish that were true. As a professional biologist, some of my most humbling experiences in the field have involved showdowns with goannas.

Early in my career, fate put me on a collision course with the Yellow-Spotted Monitor (Varanus panoptes) of tropical Australia, about the same size as a Lace Monitor. These giant lizards are the apex predators on tropical floodplains all across Australia’s Top End, and are important traditional food (bush tucker) for many Aboriginal communities. So when the Australian government approved a uranium mine slap-bang in the middle of the wet–dry tropics of the Northern Territory, the management authorities realized that we needed to know more about the ecologically and culturally significant goannas of the area. In 1982, I was given a contract to do that research. And for completeness, I was asked to look at the ecology of two other species as well: the semi-aquatic water monitors (Varanus mertensi and V. mitchelli).

I was still very early in my career—I had just landed my first academic job—and everything I knew about tropical biology could have been written on a single rosette on the flanks of a Yellow-Spotted Monitor. Nobody else knew much about the tropical fauna, either, so there were no wise colleagues to advise me. I used my contract money to hire my first research assistant—Rob Lambeck, an undergraduate from one of the Uni classes I was teaching—and to pay for our flights from Sydney to the mining town of Jabiru, east of Darwin.

The first morning after our arrival, Rob and I took a four-wheel-drive vehicle out onto the majestic floodplain of Magela Creek. To my uneducated eyes, it was like landing on a different planet—the extraordinary lushness of the wetlands, thousands of waterbirds, massive Saltwater Crocodiles sinking into the muddy water as we approached. And for a keen herpetologist, it was an intoxicating introduction to creatures I had read about in books but never seen in the wild—spectacular Frillneck Lizards (Chlamydosaurus kingii), huge Olive Pythons (Liasis olivaceus), and venomous snakes (King Browns, Pseudechis australis) larger than any serpent in southern Australia.

The goannas were there, too, but they were secretive. We eventually worked out how to find water monitors, by paddling a canoe down pandanus-fringed billabongs or carefully examining creek-crossing sites along the roads. The larger Yellow-Spotted Monitors were more widely distributed, but we could find them on the open floodplain close to the water’s edge.

Finding a goanna, though, isn’t the same as catching it. Time and again, we found goannas. And time and again, we crept up to them. And time and again, they hurtled off as we approached, into inaccessible sites like crocodile-infested billabongs and massive brush piles. It was infuriating—the lizards knew exactly how close they could allow us to approach before they moved, so on many occasions we were only a heartbeat away from launching a dive at the reptile before it evaporated in front of us.

We caught a few goannas on that first trip, mostly through luck and using 4-m (12-ft) fiberglass fishing poles with nylon nooses on the end. It was expensive work, though, because a noosed goanna would often tear off into cover, snapping the pole around an inconveniently located log. Our best success was with large male Yellow-Spotted Monitors that were courting females when we saw them. The female disappeared long before we could approach, but the romantically aroused males paid less attention to us and often were still searching for their lost loves when we slipped the noose around their necks.

On our second trip, we were better prepared. We constructed goanna traps, 2-m (6-ft) lengths of pipe with a trapdoor at one end, attached to a trigger holding smelly bait such as long-dead fish. Whenever we saw a goanna basking, but failed to catch it, we deployed one of the traps. And mostly, when we returned, the goanna was still there, but now sitting on our trap rather than secured inside it. Captures were few and far between.

Our sample sizes gradually improved, but it was a trying time. We had learned how to find goannas—lots of goannas—but the lizards outsmarted us at least 90% of the time. It was humbling.

Our breakthrough in varanid catching came when I finally recognized a paradox. First, goannas were almost impossible to catch by any of the methods that we tried. Second, Aboriginal people have been catching and eating goannas for tens of thousands of years. So, they must know how to catch these fiendishly clever lizards.

I employed a local Aboriginal man, Uncle Billy, to teach us how to do it. And it was amazing. The next time we found a large Yellow-Spotted Monitor out on the floodplain, I brought the car to a stop. Instead of hurtling toward the lizard as Rob and I had been doing, Billy just got out of the car, then stood still. And after about 10 minutes, he took a step toward the lizard, then stopped again. It was a very slow, very careful approach, with each foot placed down gently. As Billy grew closer to the animal, I expected the lizard to race away—but instead, it slowly sank to the ground, almost disappearing into the grass. And it stayed there as Billy kept up his snail-paced advance, until he eventually simply bent down and took hold of the animal. Even then, it hardly moved.

The lesson, of course, was that a goanna faced with a slow-motion approach may rely on concealing itself rather than fleeing. So, all we needed to do was approach slowly. But my confidence in solving the problem was short-lived. Neither Rob nor I had the awesome patience required for the slow-motion method, especially when clouds of biting flies descended on us. We moved too quickly, and many lizards retreated rather than awaiting capture. Still, our success rates improved, and we gathered enough data to answer the questions that we were asking.

But you have a lot of time to think as you creep slowly, step by step, toward a large lizard that may or may not wait for you to arrive before hurtling away like a turbo-charged missile. Lots of time to reflect on the advantages of studying stupid reptiles instead of smart ones. There are thousands of species of reptiles in the world, and the varanid lizards are the only ones that sneer at me. I’d prefer a relationship with animals I can outsmart. I vowed that never again would I conduct a field project on goannas.