Snake Road

Mesic bluff base forest along “Snake Road.”

Last fall, my good friend Richard Thoma and I visited “Snake Road” is a famous snake viewing area in southern Illinois—part of the LaRue-Pine Hills/Otter Pond Research Natural Area. Early October is prime season for viewing snakes there, principally northern cottonmouths (a.k.a. water moccasins—Agkistrodon piscivorus) as they move from the wetlands on the west side of the road to the towering limestone bluffs on the east side seeking crevices in which to shelter for the winter. With a string of cool nights and sunny skies and a forecasted high of 78°F, we couldn’t have picked a better day to look for them.

Shafts of morning sunlight stream through the forest.

We arrived a little after 9am, so conditions were still a bit too cool for the snakes. Shafts of morning sunlight streaming through the trees were a sight to behold, and we used the opportunity to notice some plants that we’d not seen before, including two species of goldenrod—i.e., Solidago caesia (bluestem goldenrod) and S. flexicaulis (broadleaved or zigzag goldenrod), Decodon verticillatus (swamp loosestrife), and Laportea canadensis (wood nettle). I noticed small green berry-like structures on some of the latter, which I at first took to be fruits, but something about them said “gall” and I cut one open to find a small insect larva inside verifying this to be the case. I presume this to gall to have been caused by Dasineura investita (wood nettle gall midge) in the family Cecidomyidae.

Solidago caesia (blue-stemmed goldenrod) in mesic bluff base forest.
Inflorescence of Solidago caesia (blue-stemmed goldenrod) in mesic bluff base forest.
Solidago flexicaulis (broadleaved or zigzag goldenrod) in mesic bluff base forest.
Inflorescence of Solidago flexicaulis (broadleaved or zigzag goldenrod) in mesic bluff base forest.
Decodon verticillatus (waterwillow or swamp loosestrife) in Mississippi River floodplain oxbow lake.
Laportea canadensis (Canada nettle or wood-nettle) in mesic bluff base forest.
Gall on Laportea canadensis (Canada nettle or wood-nettle), presumably caused by Dasineura investita (wood nettle gall midge).
Dissected Dasineura investita (wood nettle gall midge) gall on Laportea canadensis (Canada nettle or wood-nettle) revealing the larval inhabitant.

As we hiked south along the road (closed to automobiles during spring and fall to protect the migrating snakes), and especially when temperatures climbed above 70°F, we began looking in earnest for snakes, reasoning that they might best be found by searching along the base of the bluffs and in nearby crevices. We searched one particularly promising rock ledge without success, then encountered a spring draining from the main bluffs and followed it to the base, where we split up and looked along the base in both directions. My direction took me around a bend and up the hillside, with many nice-looking crevices but no snakes in them, and when I reached to top of the exposed bluff face I turned back and retraced my steps. Just after reaching the bottom I noticed movement near where I’d taken a step, and there it was—a gorgeously-marked juvenile cottonmouth! I called Rich over, and together we spent about a half-hour taking turns trying to get the perfect photograph of the snake while trying to minimize the degree to which we disturbed it (lest it make a dash for the nearest crevice, or worse yet, take a lunge at one of us). The majority of the photos shown here are of this individual, and the only photo I wish I would have gotten was one with a fully-extended, flickering tongue.

Juvenile northern cottonmouth (Agkistrodon piscivorus).
Juvenile northern cottonmouth (Agkistrodon piscivorus).

Our spirits buoyed by the experience, we bushwhacked back to the road and almost immediately encountered not one but two fully mature individuals—both having already lost the distinctive patterning seen on the juvenile but beautiful nonetheless. We spent more time photographing these as well, as we were able to get several great shots of the distinctly marked throat and mandible as they reared their heads in cautious defiance. I used the big camera exclusively for these shots, as they were much too large and I would have had to have gotten much too dangerously close to photograph them with my iPhone (look for photos to appear eventually on my natural history blog—‘Beetles in the Bush’).

Further south we found an exposed bluff face very close to the road, and several additional mature individuals were seen there—two deeply ensconced within their chosen crevice but one fully exposed (two photos here) who even cooperated by gaping his mouth in alarm to show off the cottony-pink tissues inside.

Adult northern cottonmouth (Agkistrodon piscivorus).
Adult northern cottonmouth (Agkistrodon piscivorus) with mouth agape, revealing the cottony-pink tissues inside that give rise to its common name.

In all, we would see nine individuals by the time we hiked to the southern parking lot and turned around, and on the way back, not trying nearly as hard and making a more direct line to the car, we would see another five individuals (two of which could have been individuals we’d seen on the way out) for a total of 14. We also watched in amazement as a tiny juvenile eastern yellow-bellied racer (Coluber constrictor flaviventris) chased down a fly on the road before dashing back towards the forest, and we were particularly amused by a nine-banded armadillo (Dasypus novemcinctus) who lumbered stupidly out of the underbrush straight towards us, completely unaware of our presence until Rich made a sudden movement with his hand that sent the little brute scurrying back into the underbrush.

Nine-banded armadillo (Dasypus novemcinctus).

Almost as we reached the car, we found a ribbon snake (Thamnophis sauritus) stretched out across the road. Snake sightings notwithstanding, the return hike back to the car was not nearly as enjoyable as the hike out, as by this time quite a number of other people had shown up and we no longer had the place to ourselves. I can only imagine what it must be like here during the weekend! Nevertheless, we couldn’t have imagined a more successful and enjoyable outing than the one we experienced today.

©️ Ted C. MacRae 2022