Predators I Have Known by Alan Dean Foster Page A

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 insufferable 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