Wind-swept Rattlesnakes

It was overcast.  Thinly veiled streaks of formless, gray-blue clouds stretched to the horizon.  The rapidly warming day was quickly approaching the perfect basking conditions that I’d been waiting for all morning.  I was feeling optimistic and energized.  The spring semester had just finished and I’d soon be heading to New Hampshire for a position at the Hubbard Brook Experimental Forest in early June.  That meant I had all of May at my leisure to pursue wildlife.  I wasn't about to waste a single minute that could be spent birding or herping.  

As I approached my destination, twenty five mph winds began to pick up.  The bare branches of trees and newly-emerged roadside greenery swayed and creaked as I gripped my steering wheel to steady myself.  Wind is generally not a friend to wildlife watchers.  It keeps the birds away and the herps under cover.  Old trees, aptly named “widow makers,” are of real concern.  Luckily, I was headed to one of Ohio’s last remaining Prairie remnants in Northwestern Ohio where the sparse trees pose little danger.  What I was there to look for, however, is another story entirely.   

I parked along a gravel ditch just as a small tree shuddered and gave way across the street.  The wind whipped across the open landscape, rustling through the grass as though hundreds of snakes were sliding all around me.  I suddenly began to understand the overwhelming sense of dread that ophidiophobes must experience when encountering a snake.  I strapped a pair of protective gaiters around each of my ankles.  There could be a concealed rattlesnake below any tuft of grass, and I wouldn't be able to see it or hear it over the gales.  

I’ve looked for Ohio’s two endangered rattlesnake species many times, but the smaller of the two has always eluded me.  Eastern Massasauga Rattlesnakes (Sistrurus catenatus) inhabit the wet meadows, bogs, and mesic prairies from New York to Ontario and as far west as Iowa and Missouri.  In Ohio, they were once considered commonplace across most of the glaciated half of the state.  Direct persecution, habitat loss, collection, and road mortality have reduced their 28 county range down to just nine remaining counties.  The eastern massasauga faces similar declines across eastern North America.  These snakes were recognized as nationally imperiled in the 70s and are thought to be extirpated from 40% of their original localities.  

Eastern Massasauga Rattlesnakes inhabit lowlands during the spring and fall, relying on crayfish burrows for cover and hibernation sites.  Water just below the surface that never freezes is a must.  If the frost layer penetrates the ground, the snakes will not survive.  Loss of suitable overwintering habitat or modifications to the water table quickly decimates massasauga populations.  Ohio alone has lost 90% of its original wetland habitat.  These snakes persist in landscapes that pose particular difficulty to agriculture, and were subsequently left relatively unchanged.

Uplands are just as important to massasauga ecology.  During the summer months, snakes move into upland forests to forage.  These landscapes are often unprotected or heavily developed, resulting in population declines even when the adjacent wetlands are protected.

With each step, water bubbled up through every crack and burrow in the mud.  I hadn’t walked one hundred meters from my car when I froze. Sitting coiled in a tight bun atop an elevated pile of dry prairie grass was a massasauga rattlesnake.  My heart raced as I took a few steps back and freed my camera from my pack.  I crept around the motionless rattlesnake, it’s dark body burning into my retinas.  Upon closer inspection, it became clear that this snake was not black, but tan with dark brown blotches; its triangular head and unblinking eyes were clearly visible through the tall grass.  Stretched out, the sauga would probably measure over two feet (these pigmy rattlesnakes max out at just under three feet).

I kept a respectful distance, well outside of the snake’s strike range, but I still didn’t want to startle the sleeping viper.  As I moved for a clearer shot of the head, the snake suddenly became aware of me.  Striking or even rattling unless thoroughly provoked is almost unheard of.  Massasaugas typically remain motionless, allowing the threat to pass by unawares.  Perplexing, the massasauga twitched in agitation with an almost copperhead-style movement as it coiled its neck and raised its buzzing tail.  I was shocked.  I’ve encountered timber rattlesnakes at closer range and never had one so much as tongue flick.  I stepped away, allowing the snake plenty of room to escape.  Butt still buzzing, the sauga slipped below the tangles of grass and out of sight.  I suddenly felt very glad I was wearing gaiters.  

I am confident that this uncharacteristic encounter was down to individual personality.  Carl Brune often tells the story of two eastern hog-nosed snakes he hatched from eggs.  One sibling would play dead whenever approached, while the other would only flare its hood and hiss.  Snakes are as much individuals as you or I.  

During the course of my search, I encountered three more massasaugas.  Two never budged as I watched and photographed them.  The third was found out on the crawl, and while it did coil up upon my approach, it never rattled or gave the faintest impression that it felt threatened.  After a few minutes, it slowly turned away and drifted off into the tall grass.  

After that first encounter, I was primed to be a bit jumpy.  I was scared half to death when a snake came lunging out of the tall grass in full strike, mouth agape.  After the initial shock wore off, I looked down to see a large, but utterly harmless, eastern gartersnake.  “What are you doing??” I said aloud, holding back laughter.  I plucked the grumpy garter from the grass and placed him off the trail.  Snakes, venomous and nonvenomous alike, have no interest in biting if they don’t have to.  All they want is to be out of harm's way.  Sadly, senseless killing by ignorant or fearful snake-haters continues.  It is not unheard of to discover a dead sauga with its rattle cut off—as a trophy.

Even where massasauga populations appear stable, a new threat has emerged on the scene.  In 2006, a fungal pathogen called Ophidiomyces ophiodiicola was discovered in Timber rattlesnakes.  This fungus targets wild and captive snakes, primarily rattlers and colubrids, in eastern North America and Europe.  It penetrates the epidermis though any small wound and causes lesions and blisters to form across the snake's head and body.  The origin and dispersal mechanism of this fungus are unknown, but it can survive in the environment without a host for some time.  Whether this fungus was introduced or a native turned virulent, it appears to work in tandem with other environment stressors like habitat modification and climate change.  Some snakes may be able to shed repeatedly to keep the fungus at bay, but many succumb as the infection attacks the deeper layers of skin, muscle, and bone.  Massasaugas are particularly vulnerable to this Snake Fungal Disease, and their already dwindling populations are being pushed closer toward extirpation by its spread.

I've visited many historical localities where the tufts of wiregrass and crayfish burrows no longer harbor wild massasaugas due to poaching and habitat modification.  Without their swamp rattlers, these wet meadows, fens, bogs, and prairies feel eerily empty.  It would be an irreparable shame to see the littlest of Ohio's vipers disappear from its final strongholds.

Thanks for reading!
Keep living the field life.
Ryan

An "Aberrant Eastern Gartersnake"

Plains gartersnakes (Thamnophis radix) are a common species from south central Canada through the Great Plains to Texas and Oklahoma.  Across this expansive range, their populations can reach densities of 300 individuals per acre.  They are not a rare snake by any stretch of the imagination.  In Ohio, however, the entire range of this species is restricted to just one county within one prairie remnant (and not even the entirety of that).  Ohio plains garters are snakes out of time.

5,000 years ago, the climate in Ohio was very different than it is today.  The Xerothermic period, as it is called, was significantly dryer and hotter by as much as five degrees Celsius with 25% less rainfall.  For several thousand years, Ohio’s climate closely resembled modern day Kansas.  This warm, dry period was marked by an expansion of western biota into the state.  Flora and fauna that we associate with the great plains, found suitable habitat in this “prairie peninsula.”  When the climate shifted again (to the cooler, wetter present), the prairies receded, leaving behind a few isolated prairie pockets where clay soils inundate the landscape for much of the year (such as on ancient riverbeds), preventing the expansion of forests.  Today, agriculture has reduced the 12,000 ha of contiguous wet prairie across northwestern Ohio to a few thousands disjunct hectares.  

The entire Ohio Plains Garter population is so localized that these snakes were not verified in Ohio until 1945.  Even the great herpetologist, Roger Conant, who collected the first specimen in 1931, mistook the washed-out DOR (dead on road) snake for an “aberrant eastern gartersnake.”  This is the ultimate case study in local abundance.  While these snakes would have originally inhabited a larger expanse of the available prairies in Ohio, habitat loss and land-use changes have reduced their already limited populations by as much as 94% in some areas.  Where they still occur, there can be hundreds per acre.  However, the sympatric eastern gartersnake (Thamnophis sirtalis sirtalis) outnumbers the plains by about ten to one.  If I had any hopes of finding a plains, each and every striped snake I discovered would have to be thoroughly examined.

A terrestrial crayfish burrow 

In preparation for a long week of finals, my girlfriend, Julia Joos, and I decided to take a weekend herping trip to unwind.  We arrived in northwestern Ohio in the evening, anticipating an early morning search the following day.  The weather, however, had other ideas.  That night brought storm clouds and frigid temperatures that stuck around until late afternoon.  The clouds finally burned off just a few hours before sunset.  We hoped the timid sunshine and mild temperatures would be enough to entice the snakes to bask. 

The flat expanse of fields and croplands intermitently bisected by roads might not look like much to the passing observer, but I could tell right away that this habitat was great.  Hollow mud chimneys—the entrances to the burrows of the terrestrial crayfish species Falicambarus fodiens—were everywhere.  These burrows are not only a sign of high water quality and good soil chemistry, they also provide the snakes with refugia during inactive times of the day and year.  Modify the water table or introduce pollutants that wipe out the crayfish, and the snakes will invariably disappear along with them.  

In early spring, the vegetation is still brown and brittle, weighted down from months of snowpack.  With their lateral stripes, gartersnakes camouflage perfectly among the criss-crossing network of dried reeds.  I hiked quickly, scanning the ground and listening for rustling movement.  Julia was more careful.  She found the first snake of the day in a spot I had tromped right over.  It was an eastern gartersnake, still muddy from the crayfish burrow it had recently emerged from.  During the next hour, we found half a dozen more garters, but none were quite what we were looking for.  I finally resolved to photograph one of the more colorful individuals coiled up among the mud and grass.  As I set up my camera, Julia called out from just over my shoulder.

“Oh, here’s another one!” she said.  I turned around to see a large gartersnake coiled among the grass.  “Nope!” I laughed, “that’s our radix!”  Had I not been looking for the subtle defining characteristics of the plains garter, I easily could have passed this snake by.  Even through the snake’s mud-dusted scales, I could tell its stripes were unusually black.  The dead giveaway that this was our plains garter, however, was the yellow-orange stripe running the length of the garter’s back.  Out of the hundreds of variations of the eastern gartersnake that I have seen over the years, none have had a stripe quite that color.

The garter cooperated nicely, coiling in front of us and tongue flicking.  After a few shots the snake decided it had had enough, and zipped away through the grass.  The purpose of those stripes becomes clear when a garter flees through a vegetated landscape.  longitudinal stripes make it significantly harder to judge the snake's speed, length, and direction.  The plains garter seemed to almost meld with the landscape it so depends on. 

A juvenile plains gartersnake (Thamnophis radix)

On a return visit to the area a few weeks later, I was lucky enough to find a juvenile plains gartersnake, a good sign that these endangered snakes are breeding.  Despite the perilous predicament these snakes find themselves in, very little management is directed towards their conservation.  Reintroduction efforts through captive breeding have been underway for years, but these snakes still face a host of threats in their final stronghold.  The landscape they call home is primarily managed for waterfowl hunting.  Scheduled mowing of their field habitat has been shifted to coincide with snake inactivity, but individuals are still occasionally killed.

Like that first specimen found by Conant in the 30s, road mortality is one of the easiest ways to discover this species.  I found a large adult T. radix, carelessly crushed by a speeding vehicle as the harmless snake attempted to cross between habitat patches.  Even though plains gartersnakes are common across the great plains, the disjunct populations in Ohio, Missouri, and Illinois all represent unique genetic lineages.  They are important contributions to the biodiversity of our state and to the persistence of these remaining prairie patches.