I went rattlesnake hunting last Saturday. Guided by Tom Anton, who works in the fish department at the Field Museum and pursues snakes as an avocation, I wandered through several forest preserves along the Des Plaines River peering under hummocks of grass and turning over logs. I am still trying to decide whether this was a rational activity.

I am mildly phobic about snakes, probably as a result of being raised by a mother who can’t stand to look at even a picture of a snake. In my career as an outdoorsperson, I have gone to some lengths to avoid contact with dangerous snakes. Most of my outdoor time has been spent in the great north woods, a land of bears and dangerous weather but no venomous reptiles.

My first real experience walking around in snake country was in the early 70s, when I did some hiking and backpacking with my wife in Arkansas. All the books said timber rattlers liked rocky hillsides, and that happened to be almost the only kind of place there was in the Ouachitas and Ozarks. My steps were short and slow. To get a better look at the ground I walked bent at the waist, and I lifted my feet so high between steps that I looked like a man trying to see if there was dog shit on the soles of his shoes. With steady application I could cover about a mile an hour in this style, so Glenda began to take the lead on our hikes. She grew up in the Ozarks and didn’t seem to be bothered by the fact that she was walking over ground where the ranges of the timber rattler and the western diamondback overlap. Where copperheads slithered along the ridges. And down in the creek bottoms–cottonmouths.

Finally, moved by that deepest human terror, the fear of looking silly, I started to walk around with an assurance I usually didn’t feel. But along the Des Plaines last Saturday, I was deliberately breaking the rules of snake avoidance, going out of my way to get close to a pit viper. I was picking up large boards, two-by-tens and old sheets of plywood, and flipping them over. Sticking my hands–or at least my fingertips–under these boards to prize them out of the ground.

Our search was unsuccessful. We found three garter snakes–two with the opaque, sightless eyes of serpents about to shed their skin–one masked shrew, and lots of ants and other insects. But no rattlers. I was hoping Tom would find a snake for us and spare me the tachycardia that would follow my discovering one. But I was also hoping I would find one and establish myself as a fearless snake hunter.

Massasaugas are small rattlers. The biggest are only a little over three feet long–about half the size of the biggest timber rattlers. Anecdotal evidence says their fangs cannot stab through the leather of an ordinary hiking boot. There is no known instance of a human dying from the bite of a massasauga, and very few instances of anyone being bitten. Anybody who has hung around them much says they are very unaggressive snakes, animals that defend themselves mainly by keeping still and hoping you don’t see them.

The massasauga is the only venomous reptile native to the Chicago area. I should note that “venomous” not “poisonous” is the correct term. A poisonous snake would be a snake that killed anything that ate it. Venomous snakes poison the things they eat. When settlement began, massasaugas probably lived along the Des Plaines (as they do now), in Du Page County (where they have been extirpated), and in extreme southern Cook County (where they may still survive). The last sighting by a biologist at the southern site was in 1989, but local residents say they have seen some since then. Ken Mierzwa, who has been studying local reptiles for years, says that the possibility of a snakebite tends to blunt people’s observational powers. “Fox snakes vibrate their tails. Hitting dry leaves, they can sound like rattles. People say they saw a rattlesnake, but then they show you an out-of-focus Polaroid of a fox snake.”

Our local massasaugas seem to have rather precise habitat requirements. They live along the borders between bottomland forests and wet prairies, or along the edges of a distinctive type of northern Illinois forest called a flatwoods. Mierzwa says they are found only in soils underlaid by a clay hardpan, and they appear to be dependent on the prairie crayfish to provide them with places to hibernate. The crayfish digs a burrow six feet deep with an enlarged chamber at the base that is big enough to hold a sleeping snake.

There are three subspecies of massasauga in North America. The eastern can be found in ever-declining numbers from southern Ontario and western New York to western Iowa. The western is the typical form in the area from western Iowa south and west through Kansas, Oklahoma, and Texas. The desert form lives in west Texas, New Mexico, and southeastern Arizona.

Massasaugas have been unfortunate in their habitat preferences. In Ontario and New York they live in wetlands. Some hibernate under sphagnum-moss hummocks in northern bogs. They are excellent swimmers, as evidenced by their presence on islands in Lake Huron. Of course we know what has happened to most eastern wetlands.

Here, as I said, they like places where bottomland forests meet wet prairies. One of their big problems throughout Illinois has been the lowering of the water table, a change that has come about both through heavy use of groundwater and through the effects of drainage projects. Many formerly wet areas are now dry and either plowed or paved. The range of the massasauga in Illinois has been reduced by two-thirds since settlement began, and within that range the animal maintains only small, scattered populations.

The western snake lives in the tall-grass prairie, especially along watercourses, so it too has lost much of its habitat. The desert massasauga is an animal of the desert grassland, a community that has been devastated by overgrazing and fire protection.

Animals of wetlands or river bottoms can easily develop a scattered, islanded distribution. Floods can carry them for miles, allowing them to create new population centers far from their original homes. But the naturally patchy distribution of the massasauga suggests that it is a relict, an animal that spread across its considerable range in a time when a different climate produced different vegetation. Climate changes over the past few thousand years could have shrunk the favored habitats and left much less room for this snake.

The accelerating decline of the massasauga has led to proposals that it be listed as an endangered species. It is on the “watch list” in Illinois, and biologists with the U.S. Fish and Wildlife Service are currently reviewing the possibility of a listing at the federal level.

There are definitely political considerations involved in putting a rattlesnake on the endangered list. Tell people there are venomous snakes in that forest preserve just behind their houses and many will start fantasizing about eight-foot cottonmouths coiled in the baby’s crib. Conservatives will have great sport with the airhead environmentalists who have all sorts of ideals and no common sense. The commonsense approach, of course, is to ruthlessly exterminate anything that might possibly annoy you in any way. As late as the 60s people were still running rattlesnake roundups in Wheeling.

The massasauga is a predator that feeds high on the food chain. Voles and mice are its main foods. It grows slowly, and females reproduce only every other year. It is never going to be as common as, say, garter snakes. It is so shy and retiring that you would have to make a serious effort to get one to strike at you. The chance of it being a menace ranks just below the chance of being bitten to death by a huge pack of Yorkshire terriers.

Still, I am glad that we have the massasauga as at least a possible danger. Motorcycle gangs are the only scary things in most of our forest preserves, and we should have something natural that can command respect. Knowing there are snakes around raises your level of concentration. It suggests the power that resides in nature. Americans are traditionally devoted to taming or conquering nature, hence our murderous ways. If we were willing to recognize nature as a genuine great power, we could work out accommodations rather than seek conquests. Which means we could leave the snakes alone and stay alert enough not to step on one.

We were very alert last Saturday, but it did us no good. The weather was working against us. It got very hot early, so the snakes were coiled up in the coolest, shadiest places they could find. With their cryptic coloration, they would be practically invisible to a human searcher. Tom Anton is a serious student of this snake–a friend called him the Jane Goodall of the massasauga. And if he couldn’t find any, they must have been lying very low.

Anton has observed these snakes so carefully and for so long that he has devised a way to identify individual animals. The patterns of spots on a snake’s back are, he says, “like a thumbprint.” In one snake the 24th and 25th spots, counting from the head, will be joined together. Another animal might have no joined spots, and another might have the 15th and 16th fused. Ellin Beltz, who is currently preparing a report on massasauga populations for the Illinois Department of Conservation, calls Anton’s work, including the identification system, “cutting-edge herpetology.”

Anton has been studying the snakes along the Des Plaines for years, watching their behavior and charting their movements using his ability to recognize individuals. His work will provide another insight into the complex workings of ecosystems, the real building blocks of life. But he can keep doing that work only as long as the ecosystem and all its parts continue to exist.