National Geographic : 2013 Feb
100,000 VENOMOUS ANIMALS* 20,000,000 ESTIMATED TOXINS 1,000 STUDIED IN DEPTH 10,000 KNOWN TO SCIENCE THE PRODUCTS OF VENOM** 10-20 medicines 10-15 diagnostics 1 cosmetic Spiders 20 Corals, sea anemones, jellyfish 6 Lizards, snakes 1% Centipedes 2 Marine snails 5 Other 1 Mites, ticks 1 Fish 1 Scorpions 1 Insects 62 blue-ring octopuses, and a host of toxin-spewing fish about which little is known. And cone snails. Lovely as jewels, each of the more than 600 Co- nus species concocts a unique and wicked brew, some strong enough to kill a person with a single shot. (No matter how pretty it looks, never put a cone snail in your pocket.) After a shallow dive, Takacs strolls along the water’s edge holding treasure: a sea krait wrig- gling in one glove and a fist-size cone snail in the other. “ The best the sea has to offer,” he grins. “I have hundreds of toxins in my hands.” The cone snail’s shell is a gorgeous mosaic of brown paint- daubs on white. After I admire his finds, Takacs drops the snail into a seawater-filled container for later examination. Snakes are his first priority. Always equipped with a sampling kit, Takacs sets up a basic field lab on the boat: lidded con- tainers, tubes filled with preservatives, syringes and needles, a pair of snippers for tissue sam- pling, a camera for documenting each animal’s patterns, and a big black glove. Sea kraits are quite passive, so the chances of getting bitten are almost nil. But Takacs wears the glove anyway. He’s allergic to venom, which would cause him anaphylactic shock in addition to its usual para- lyzing effects. He’s also allergic to antivenom, made with serum from horses, so it’s extraordi- nary that he’s survived a total of six snakebites. I help by holding the snake’s tail, belly scales up. Takacs grips the biting end, stretches the snake to its length, and runs a finger down the body, feeling for the heart. When he locates it, pulsing against the skin about a third of the way down, he carefully inserts a needle and draws blood. He also clips off a fragment of tail tissue and shoots a few photos before setting the snake back in the water and watching it swim away. Takacs processes numerous snakes this way during our days on the water. And anytime we encounter local fishermen, he motors up to ask about their sea snake sightings, hoping to hear of other species in the area. “If you see the one with the yellow and black bands,” he says, “would you let me know?” Indeed, one day he was sum- moned to the dock, where a slender-necked sea snake awaited in a bucket. Takacs is known to have engaged entire villages to look for snakes. In Fiji, and wherever else he collects ven- omous animals, Takacs is adding to his venom library. Meanwhile, in the lab he teases out varia- tions in the makeup of toxins between species, within species, and even within populations. He also investigates what makes animals resistant to their own venom—information that could help yield better venom-derived therapeutic drugs. I was surprised that Takacs wasn’t milking the venom of the sea kraits, but he explained Untapped bounty A single animal’s venom can contain hundreds of different toxins that immobilize, harm, or kill. Because the toxins target body functions selectively, they’re ideal for developing drugs. Only a fraction have been studied. *Conservative estimates for major groups of venomous animals. **Numbers are approximate because classifications vary.