Encounters With Canebrakes

Views:

363 views
in_situ_canebrake.jpg

“Canebrake” Rattlesnake is an established alternative common name for the Timber Rattlesnakes (Crotalus horridus) of the Southeast Coastal Plain. Canebrakes differ from Timbers by reaching a greater size (4.5-6 feet; most adult timbers are 4-4.5 feet in length). Canebrakes are pinkish to tan in color and are marked with a prominent rust-orange stripe that runs down the middle of the back. While Timber Rattlesnake populations are often associated with rugged and rocky terrain like mountain forests, the low-country (i.e., Coastal Plain) Canebrakes generally inhabit heavily-wooded stream corridors and the shadowy margins of swamps. Below, I attempt to recapture some of my remarkable field experiences with the Canebrake Rattlesnake.

What on earth is that snake up to, I wondered. As I eased downslope I spotted a massive Canebrake Rattlesnake at the base of a large oak tree. I looked on as the rattler snaked/extended/stretched most of its heavy body up the fat gray trunk of the oak, laboring to lift its body as far off the ground as possible. Head held close to the bark, tongue-flicking continuously, the snake swept its head from side-to-side in a wide arc over the trunk—as if searching. Occasionally, gravity took over and the body of the four-foot rattlesnake would fall awkwardly to the ground with an audible thump. The snake would instantly pop up, extend its form skyward, and resume sweeping the trunk.

The snake disappeared from view. I approached as softly as I could and found the animal on the far side of the oak in the early stages of swallowing an adult flying squirrel. Apparently, its odd movements on the oak trunk were related to searching for its just-envenomed prey. How the rattlesnake located this nocturnal rodent during the late morning is a mystery.

Of course, these advanced snakes are very good at what they do. A hungry rattlesnake becomes a sit-and-wait predator par excellence. From a conversation with rattlesnake expert Jayme Waldron I learned that larger Canebrakes commonly hunt grey squirrels by positioning themselves in what herpetologists term a “vertical tree ambush posture” on the trunks of oaks and hickories frequented by the squirrels. If you walk bottomland hardwood forests all summer staring at tree trunks you will find one eventually, Jayme offered. (Now, yet another compulsion accompanies me in the field…).

In fact, I have found several foraging rattlesnakes situated just as described by Jayme. I checked on one of these snakes on three consecutive days. My field notes read: Day 1– Spotted a big Canebrake in mature oak bottoms above blackwater creek swamp.. Gorgeous snake, ca. 4.5 feet long…found @ at base of laurel oak at 1130 hrs; Day 2: Using binocs, viewed snake from 30 feet; found (him?) @ 1415 hrs in very same pose and place as yesterday, hasn’t moved a muscle… flower petal still stuck to snout. On Day 3, I again snuck up to the tree. A wave of melancholy hit when I realized the snake was gone. Then, walking out from the oak I found the snake 10 feet away sporting a belly hugely swollen with prey. According to herpetologist Paul Moler, some—but not all—Crotalus horridus in southeastern Georgia possess a complex and highly potent neurotoxin (“Canebrake Toxin”), making their venoms extraordinarily lethal.

Of course in nature turnabout is fair play, and Canebrake Rattlesnakes have their share of predators. Great horned owls, skunks, opossums and coyotes all come to mind. And yes, even other snakes. My colleagues in southern Georgia have sent me several photos of big Eastern Kingsnakes swallowing Canebrakes, and Indigo Snakes followed via radiotelemetry in south Georgia were observed swallowing velvet-tails over three feet long (both of these serpents have evolved an immunity to viper venoms). The scats of these Indigos contained rattle fragments. Last month, while driving south of Athens on Highway 441, I saw a Red-tailed Hawk lift from the grass along the shoulder, a small snake squirming in its talons. The hawk dropped the snake, and I was able to recover and photograph the little snapper, a young-of-last-year Canebrake that, except for a small laceration on its dorsum, appeared to be ok.

In the Coastal Plain, female Canebrakes produce young for the first time at around six years of age, and subsequently reproduce every 2-3 years. They give birth to, on average, about a dozen, foot-long babies. Rattlesnake mothers are careful and secretive; their birthing sites are typically well-hidden and protected by cover. A few years ago, along with another field biologist, I surveyed for Gopher Tortoise burrows at a site in the Altamaha River basin. As we picked our way through a hip-high clump of saw palmettos, we spotted colorful and rubbery patties of scales perched coiled on fronds. My goodness, who would have thought newborn Canebrakes would climb several feet off the ground to sun on a palmetto frond! We located 4-5 baby rattlers on fronds, and an equal complement curled close to the entrance of an old, leaf-packed armadillo burrow. The little guys/gals were brand-spanking new, awaiting their first shed skin event after which they would disperse and begin foraging for small mice and shrews. We found Mother Rattlesnake nearby, thin and resting, cratered up under the patch in a tight coil.

Rattlesnakes are among the longest-lived of our snakes, with Timber and Canebrake Rattlesnakes sometimes enjoying longevities of from 20–30+ years in the wild. Now, we low country old-timers have our secret spots, fields of tin and piles of debris resting near derelict buildings where Canebrakes regularly overwinter. “Flipping tin” in the early spring we commonly find many of the same rattlers year after year. A long-rattled female we recaptured this April was noticeably thin, seemed weary, her eyes blue with imminent shed. After putting on a new suit, her survival will hinge on whether she forages successfully.

Wanting a challenge, this April I hiked one of my favorite Coastal Plain sites, a marvelous Savannah River bluff vegetated with plants more typical of Appalachia. I walked for hours up and down ravines—in the valleys of which dribble clear sand-bottomed brooks—forested with white oaks, American beech, and umbrella magnolia. May apples and trilliums carpeted the floor. I wanted to find and photograph a Canebrake in its natural element. Not a snake on a road or under an old car hood. A wild rattler. I chose a perfect weather day for snakes, low 80s but with intermittent sun. With all the recent rain, snakes would be on the surface warming up, drying out. I enjoyed a quick start, finding an Eastern Hognose, then a stream of courting Racers, a small Copperhead. Several hours passed, then several more, my hike turning first into a very long walk, and then transforming into a journey. A light gap in the forest ahead marked the demise of a giant oak; insects and skinks sunned and jumped about on a fossil of a stump.

And there it was. I spotted the beautiful Canebrake, every bit as stout as most adult Eastern Diamondbacks, as it lay motionless, stretched out its full length with its chin resting on a fallen limb. I got a couple of quick photos then let the master of this forest alone. Spitting a mosquito I smiled, and satisfied, I began my walk back.