It was late summer, the stormy end of the monsoon. No sensible person who wanted to come to Putao District, Kachin State, in uppermost Burma, would contemplate going there during the rainy season. But frogs love water, and where there are frogs, there are snakes to eat them. Joe had expected muddy trails, bad food, and squalid campsites; as far as he was concerned, that was all part of the fun. Yet this expedition set a new standard of misery. The rain had poured almost incessantly since they set out from Putao, the small town that served as the administrative capital of this isolated region. The trail was a deep river of fine, clinging clay mud. Malarial mosquitoes and sharp-biting sandflies swirled in tormenting clouds; legions of thirsty leeches lurked in every dank, dark recess.
Most dispiriting of all, the snake collecting had been poor. Yes, rain brings out snakes, but not when it’s as heavy as this. How can you find snakes to catch when the rain sheets down so densely that you can scarcely make out the back of the hiker ten feet ahead of you?
On September 9, the expedition reached a village called Rat Baw, by far the most advanced settlement the group had seen since leaving Putao. It even had a street paved with cobblestones and a frame schoolhouse with a tin roof—rare luxuries in a region where most people shared smoky bamboo huts with their livestock. The scientists made their camp in the school, the first dry berth they had had in many days. Their luck finally seemed to be changing: The afternoon they arrived the sun came out—and so did the snakes. Joe and the other herpetologists immediately headed into the forest to search for reptiles.
Nobody alive knew more about kraits than Joe Slowinski did. One thing he knew was how tricky they can be to identify, for there are nonvenomous snakes that mimic them with amazing accuracy. Joe had recently discovered one such species and named it himself. Lycodon zawi, a wolf snake, imitates the krait’s alternating black and white bands so closely that it’s difficult to make a definite identification from a few feet away.
Another species, Dinodon septentrionalis, is a dead ringer for the krait. The nonvenomous Dinodon mimics the many-banded krait so uncannily well that even an experienced herpetologist might need a magnifying glass to tell them apart. The only way to be sure is to examine the snake’s head, to see whether what is known as the loreal scale is present, just below the eye: a fleck scarcely bigger than a snowflake, a tiny pentagon of horny skin that tells the difference between a harmless, handsomely banded Dinodon and the lethal krait.
This classic example of mimicry evolved millions of years ago, when predators avoided snakes that resembled the venomous krait, giving them an edge for survival. Nature didn’t give the Dinodon venom, but it got the next best thing: a resemblance to the deadly many-banded krait, which makes snake-eating predators shy off.
More interesting to Joe, however, were the snakes that he and the other herpetologists were still carefully logging as Bungarus multicinctus; the many-banded krait (a name coined in 1861 by Edward Blyth, a British zoologist in Calcutta) probably belonged to other species. In 2001, the consensus was that the scientific name Bungarus multicinctus comprised several different species of krait, which were still waiting to be collected and identified by a skilled herpetologist. Joe Slowinski thought he was just the man for the job.