Predators I Have Known

  The best shoes I’ve found for reef walking are the booties scuba divers don before slipping on their fins. Booties are tough, designed to be submerged in salt water all the time, and many styles are equipped with ribbed soles suitable for limited hiking. They come with an added benefit in that they can be used with fins, even if all you do is snorkel. Compared to booties, expensive reef-walker shoes, Tevas and their clones, and plastic sandals don’t hold up. If you don’t have booties, I suggest bringing along a pair of expendable sneakers.

  Because it’s not only the inanimate sharp-edged coral that you have to look out for.

  Reefs and their inhabitants are among the most amazing places on the planet. But like every other ecologically rich biota, they are home to hunters as well as the hunted, and sometimes the hunters are less than obvious.

  When discussing diving I’m often asked, “Aren’t you afraid of the sharks?” Let me tell you—whether on land or in the water, it’s not the big predators you have to worry about. It’s the little guys. The chance of being attacked by a shark, or a lion, or a bear, is far smaller than that of contracting a tropical disease, or acquiring an inimical internal parasite, or a persistent infection. It’s smaller than that of meeting up with one of Nature’s miniaturized but no less deadly predators. As any Australian who has been stung by an irukandji jellyfish (and survived) can tell you.

  Cephalopods are all carnivores. Their class is comprised of squid, octopus, cuttlefish, and that living fossil, the chambered nautilus. They are the most intelligent of all invertebrates. Unlike a fish, when you confront a cephalopod, especially a cuttlefish or octopus, and gaze into its remarkably advanced eyes, you get the distinct feeling that something is looking back at you and . . . thinking. Their parrotlike beaks are powerful enough to crush the shells of mollusks to get at the edible flesh within. When biting, some species drip toxins of varying potency into the wound they inflict in order to help immobilize their prey. Sadly, they only live two or three years. I’ve always wondered how our species would have fared if intelligent cephalopods enjoyed life spans akin to that of humans. Perhaps one day genetic engineering would allow . . .

  “Come look at the pretty octopus!”

  I was preoccupied with examining some small fish isolated in a tidal pool when JoAnn called out to me. At her shout, I immediately left the fish to their sanctuary and carefully made my way over to my wife. Kneeling in shallow water that occasionally lapped over her ankles, she was poking and prodding at something just beneath the surface. I couldn’t see what it was until I drew much closer.

  When I saw what it was she was toying with, I’m sure my heart skipped a beat.

  “Stop that,” I said. I think I was too taken aback to speak loudly. “Stand up and step back.”

  She looked up at me. “Why? Isn’t it pretty?”

  “Please, hon. Just step back.”

  As a point of pride as well as amusement, JoAnn will usually argue anything with me, grinning as she does so. There must have been something in my voice, because she looked at me uncertainly and then, thankfully, stood up and took a step backward. She was wearing tough but open-toed sandals. Grateful for my ankle-high diving booties, I advanced gingerly and leaned over to get a better look at what she had been casually fingering. If I had guessed wrong as to its identity, I would be forced to own up to my ignorance. A cloud momentarily slid in front of the equatorial sun, fortuitously eliminating most of the glare coming off the gently rippling water.

  I hadn’t been wrong. As an ex–veterinary technician, my wife knows animals, their habits, and how to handle them. She knows the wild creatures of Texas and Arizona particularly well. But the only places in Texas and Arizona where you’re likely to encounter meandering cephalopods are the cool depths of public aquariums.

  Irritated by the attention and exposed by the receding tide, the octopus working its way over and through the miniature coraline canyons was smaller than my closed fist. I knew it was annoyed by all the interest it had attracted because of the bright, black-lined, almost iridescent blue rings it was presently flaring all over its tiny body.

  My abrupt concern for my wife was due to the fact that this was a blue-ringed octopus; a species with a seriously poisonous bite. How poisonous? The venom in its defensive saliva (the octopus manufactures two kinds of venom: one to use in predation and the other for defense) contains tetrodotoxin, 5-hydroxytryptamine, hyaluronidase, tyramine, histamine, tryptamine, octopamine, taurine, acetylcholine, and dopamine: a litany of poisons sufficient to frighten even a non-chemist.

  Tetrodotoxin in particular is a killer. Once this sodium blocker is injected into the body, it causes neuromuscular paralysis and sometimes full respiratory stoppage, often resulting in cardiac arrest and death. Since the victim is unable to breathe, the only chance of saving someone who has been bitten is to immediately initiate mouth-to-mouth respiration and continue it until the victim can be put on an artificial respirator. This treatment has to begin before the victim develops cyanosis and hypotension. Meanwhile, the poisoned individual can lie paralyzed but perfectly aware of everything that is taking place around them, unable to speak, breathe on their own, or indicate any symptoms of distress. It’s a virtual living death.

  Suddenly, the brightly hued little octopus doesn’t seem so adorable anymore.

  I explained all this in equally graphic but less biochemically heavy terms as we stood together, looking on from a short but safe distance away as the aggravated cephalopod continued to wriggle its way through the holes and rifts in the coral. Gradually, it calmed down, losing its warning blue rings in the process. JoAnn turned to me.

  “You’re not putting me on, are you?”

  I shook my head slowly. “You were playing with it. Touching it. It could have killed you at any time.”

  She pondered. I’ve watched my wife skin a rattlesnake with her bare hands. There’s not much she’s afraid of. “Would have been a short vacation.”

  I nodded. Sometimes it’s not only bold, but sensible, to be afraid.

  There was nothing more to say. The sun was starting to set. Silently, we turned and began the long, careful hike that would take us across the reef and back to shore.

  * * *

  Speaking of tetrodotoxin . . .

  Years later, I found myself diving in Papua New Guinea off the stern of a wonderful dedicated live-aboard dive boat called the Tiata. We were in warm, sunlit waters off the island of New Ireland, in the northern Bismarck Sea. It was an easy dive: little current, a sandy bottom, vast schools of rainbow-tinted anthias and butterfly fish, close to shore. What divers like to call an aquarium dive. No sharks to speak of, no sea snakes, nothing likely to cause trouble or pose a threat.

  But remember, it’s the little things that get you.

  The gracious, middle-aged woman diving off to my right was from Chicago. In the course of the preceding days, she had revealed herself to be a competent diver, if not a terribly experienced one. Her husband, unfortunately, was the worst diver with whom I had ever been forced to share boat space. Armed with thousands of dollars’ worth of camera equipment he had little idea how to use, he had absolutely no regard for his fellow divers, his dazzling but easily damaged natural surroundings, his inordinately patient spouse, or, insofar as I could tell, anything else save his own selfish interests. He had from the first day on board proven himself to be as self-centered and inconsiderate underwater as he was above it.

  One day, having failed to get the underwater footage he sought and, as usual, entirely absorbed in himself, he literally shoved aside my cabinmate in his grumbling haste to get a cup of java from the boat’s always-on coffeepot. I had to all but physically restrain my genial cabinmate, an ex–police forensics specialist from Australia, from bodily picking up the oblivious and obnoxious Chicagoan and heaving him overboard. The rest of us did our best to ignore our disagreeable fellow passenger while commiserating silently with his incredibly tolerant wife.

  The next morning, the insuffer
able schmuck was off somewhere hanging onto live coral and shoving his camera in the faces of helpless fish in his usual futile attempt to get good pictures so he could boast to acquaintances back home about what a great photographer he was when I noticed his long-suffering spouse collecting shells from the channel’s sandy bottom.

  Shell collecting is a harmless enough activity when engaged in on land. Underwater, where the shells frequently still boast their original occupants, it can be quite a different matter. The marine gastropod mollusks that occupy most shells tend to be harmless—but not all of them. I wasn’t watching over her—her husband was her nominal dive partner, and I was far more interested in inspecting the surrounding soft corals for tiny squat lobsters and harlequin shrimp—but by sheer chance I did happen to notice when she reached down for one particular shell. It was a large cone shell, saturated with color and the repeating geometric motifs for which its kind are known.

  Certain cone shells are also known for something considerably less aesthetically pleasing.

  When people think of harpoons, their thoughts automatically gravitate toward whaling and its dramatic, bloody history. They are not inclined to think of pretty shells. As is so often the case with Nature, this is another oversight, because cone shells are natural harpooners. Actually, what they “fire,” by means of a sharp muscular contraction, is a modified radular tooth (properly called a toxoglosson radula) that contains a powerful neurotoxin. In some species, this is a tetrodotoxin.

  That’s right. Though they look nothing alike, some cone shells and the blue-ringed octopus make use of the same ferocious type of poison. And just like the venom of the blue-ringed octopus, there is no known antidote or antivenom for the toxin of the cone shell.

  I think there are instances when I have covered more space underwater in less time, but not many. I got to the woman before her bare fingers could close around the shell. She looked at me in surprise when I grabbed her wrist and pulled her hand away. Some concepts are easy to convey underwater, others less so. I couldn’t draw a finger across my throat to indicate my concern because underwater that’s the signal for someone who is out of air. So I had to settle for shaking my finger at her confused face, pointing down at the shell, grabbing my throat with both hands, closing my eyes, and arching backward to drift limply in the water. That particular pantomime sequence is not in any diver’s manual, but it got the point across. She looked at the shell, then back at me, and nodded, eyes wide behind her mask.

  Back on the boat, I took the time to enlighten her as to what had inspired the brief but serious melodrama.

  “It was so pretty,” she murmured, “and it looked harmless.”

  I nodded. “Sure. That’s what makes it so dangerous. A lionfish looks dangerous, so nobody tries to grab it. Same with a spiny sea urchin. In contrast, a shell is just—a shell. Except when it’s a live cone shell.”

  She nodded back at me. “Maybe I’ll just stick to collecting shells on the beach.”

  “Good idea. And while we’re on the subject . . .”

  “Yes?”

  “Just in case the occasion should present itself, you should avoid trying to shake hands with any pretty little octopuses, too.”

  V

  JEALOUS ANTS, MILLIONS OF ANTS, AND REALLY, REALLY BIG...ANTS

  Southeastern Peru, May 1987

  THERE MAY BE NO OTHER place in the world as magnificently wild and biologically diverse as Manú National Park in southeastern Peru. At 3.7 million acres, approximately the size of the state of New Jersey, Manú encompasses within its boundaries 13,000-foot Andean heights, spectacular untouched cloud forest, and glorious unspoiled lowland Amazonian rain forest. More than 15,000 kinds of plants have been found in Manú, more than 625 varieties of tree can inhabit a single acre, and the park is home to more than 800 species of birds, almost as many as in all of North America.

  Only a small part of this extraordinary example of still intact Amazonia is open to the public. Another somewhat larger section, mostly along the Alto Madre de Dios River, has been made available by the Peruvian government for mixed use. The great majority of the park is maintained in its original, natural, untouched state and is open only to scientists and government-approved explorers. Within its boundaries can be found perambulating spectacled bears, the raucous cock-of-the-rock (Peru’s national bird), innumerable snakes, macaws, parrots, primates, giant otters, giant catfish, rare black caimans, piranhas of varying size, species, and disposition, towering trees, entangling vines, the dreaded candiru, at least two human tribes that have essentially no contact with the outside world, and potentially thousands upon thousands of undiscovered, unnamed, and unstudied creatures of every order and genus.

  There are also an awful lot of ants.

  I first visited Manú in 1987, the year it was declared a World Heritage Site by UNESCO. At that time, there was no place close to the park’s boundaries where interested visitors could stay, and certainly nowhere within them. Besides the single primitive ranger station precariously situated at the edge of the Manú River near the entrance to the park, a single scientific station was located much deeper inside the park boundaries on the shores of Cocha Cashu, a small oxbow lake. Quite properly, this facility was and still is closed to non-researchers. In charge of its supervision was the eminent ecologist John Terborgh, whose book Requiem for Nature, set largely in Manú, I highly recommend.

  Asking around the modern Andean city and ancient Inca capital of Cusco (or Cuzco, or if you want to really be a stickler, Qosqo in Quechua) about the possibility of visiting Manú, my traveling companion Mark and I were told to try and find a certain Boris Gómez Luna, as he was the only one who could conceivably arrange such a visit on short notice. Though his name made him sound like a character from a John Le Carré novel, Boris turned out to be a slight, charming fellow whose unexpected youth was matched only by his dedication to and enthusiasm for the wild Manú. Though in the years that have passed Boris has since moved on to bigger things, his enthusiasm for Manú has never flagged.

  Señor Gómez Luna, we learned, was in the process of building the first facility inside the park that would be permitted to accommodate non-researchers. In other words, visitors like Mark and myself. Could we possibly, we inquired when we finally managed to track him down, make some arrangement with him to spend a week or so in Manú?

  “I can organize it for you,” he told us in his excellent English, “but nothing is finished there. We’re still in the beginning stages of construction, and you’ll have to sleep in a tent like the rest of the construction crew, eat the same food, utilize the same facilities. And you can’t bring much with you. I need the space in the truck for supplies.” We immediately and eagerly accepted, and a price was agreed upon.

  Two days later, we were picked up by Boris in his hulking, specially reinforced Nissan Patrol 4x4 and struggled to squeeze ourselves and our backpacks in among the mountain of materials and equipment he had collected for the journey. The road out of Cusco soon turned from pavement to dirt and began to wind its way through high treeless mountain canyons horizontally striped with perfectly level ancient Inca stone terraces. Vistas turned grand and wide. Like mice in a nest, simple houses clustered together at the bottom of increasingly deep river valleys. Irregularly shaped irrigated fields and neat square plots linked the vast expanses of bare rock together like bright green patches on a heavily weathered gray overcoat.

  Many hours later, we reached the high pass near the turnoff to Tres Cruces and came to a stop. Though the view over the clouds and mountains to the east was as spectacular as it was sobering, I found myself wondering about the delay. Boris proceeded to explain.

  “From here all the way down to the Upper Madre de Dios, the road is one way. From noon to midnight, traffic is allowed to go down. From midnight to noon, traffic can come up.” He checked his watch. “We must wait a few more minutes.”

  Hacked, hoed, and blasted out of winding, cloud-forest-swathed, perpetually damp and foggy mountainsid
es, the road from the Tres Cruces turnoff down to the backcountry Amazonian town of Pilcopata offered one of the two most hair-raising drives I have ever experienced (the other was also in Peru, from Chachapoyas to the citadel of Kuelap). Everyone is afraid of something. Sharks, bees, spiders, the dark, enclosed spaces: Me, I don’t like heights. So I was thankful for the thick clouds and mist that blotted out the view below us.

  Hours later and only partway to our destination, we encountered a characteristically overloaded truck illegally making its way upward. The Patrol halted, sliding slightly on the muddy track. It had been in four-wheel-drive mode ever since we had commenced our descent.

  “You might want to get out of the car and watch,” a thoughtful Boris advised us. Mark and I hastily complied, beating a judicious retreat up the rain-swept road. Standing there in slick, shallow mud with a light drizzle falling, we watched open-mouthed as our genial and unflappable host and the tight-lipped truck driver embarked upon an agonizingly slow, incredibly patient, and exceedingly dangerous vehicular pas de deux. While the clumsy, top-heavy truck scraped and hugged the fern-encrusted rock wall, Boris gingerly edged the Patrol around it. At one point, the 4x4’s rear right wheel was literally hanging over a sheer drop with nothing beneath it save hundreds of feet of fog. Eyes wide, we held our breath until the wheel once more caught solid ground and dug in, and the pass-by was complete.

  Wiping mist from my forehead and face as I clambered back into the Patrol, I was unashamedly unstinting in my praise of Boris’s driving. Having just casually cheated death and disaster, he shrugged off our compliments.

  “I have to do it all the time. Nobody pays much attention to the guidelines.”