Monday, August 10, 2009

The Road Less Traveled

As I slowly coasted the truck to a stop, I rolled down the window and gazed in amazement at what lay before me. Sprawled out on the pavement, encircled by alternating red, yellow, and black bands, was a dead coral snake; the first I had found despite sharing their habitat for five years. This highly venomous snake is as secretive as it is deadly, living nearly their entire lives underground. Recently, a coral snake was found in Coosa County, Alabama, after not being observed there for forty years. You can be assured they were there the whole time though, evading prying eyes due to their low-profile lifestyle.

It’s nearly impossible to make a successful, targeted search for coral snakes, even if you know they’re in the area, you just have to hope that one may show up while you’re out in the woods. Unless, of course, you’re the beneficiary of perhaps the most effective snake sampling technique out there: other people’s tires. In the course of finding mates, food, or more preferable temperatures, snakes are often required to cross roads, where they may be killed in high numbers. If you pay attention, you may realize that the roads on your daily commute are littered with the bodies of hapless snakes. If you don’t pay attention, you may be the reason why.

If you time your trip right and pay attention to the weather, driving along roads may be an effective way of surveying local snakes, especially if you pass by wetlands. The best conditions are thought to be at night after heavy rains, when the moon is not full. Although, not all species have the same preferences. If it’s a heavily traveled road, you can tally the dead snakes to get ideas about their abundance in the area. But your data collection need not stop there, for many specimens found dead on the road (or, DOR), I routinely collect them in re-sealable plastic bags, store them in a cooler, and later collect information such as the snake’s species, weight, length and sex. I’ve learned to politely smile and wave passing motorists by as I’m completing this unglamorous and occasionally odorous task. Although I strongly believe in the merits of environmental education, sometimes it’s just not worth it.

Many museums and universities hold vast collections of dead turtles, snakes, lizards, frogs and everything else you can imagine. Most of the snakes I collect end up in Auburn University’s vast collection. The specimens are used to help teach anatomy and species identification to students while researchers use the animals to test hypotheses about morphological variation and geographical distribution, among many other questions. These collections also represent baseline information about what animals were found in a particular place and time. This is particularly important when describing a new species or documenting an already known species in a previously unknown area.

My research interests include figuring out what snakes eat. Specifically, I’d like to know what snakes eat when they live in the same habitats as potential competitors. If two species eat the same things when they’re apart but feed on different types of prey when they’re in the same area, it suggests that interactions between them have influenced their behavior. Collecting and dissecting snakes found DOR allow me to non-invasively sample and answer these types of questions. For example, in 2007, I, and others, published a paper describing the habitat surrounding areas where timber and eastern diamondback rattlesnakes were found in southwestern Georgia. By comparing many of these locations, which were collected over several years, we found that timber rattlesnakes preferred to live in hardwood forests close to creeks and rivers. Diamondbacks, on the other hand, weren’t as picky about where they spent their time but they did like large areas. The differences in habitat use between these closely related species may reduce competition.

Paying attention to snakes found on the road allows me to answer questions I couldn’t have thoroughly addressed within the confines of a structured study. The next time you’re driving along, minding your own business, and spot a snake crawling across the road, imagine how hard it would’ve been to find if you had actually been looking for one.

In mid-July, while I was walking through the woods at 6:40 AM, I stumbled across this live coral snake. I'd like to say I was looking for them, but really I was scanning the treetops and listening for birds. If I hadn't accidentally startled the snake and lead it to rustle quietly in the underbrush, I never would've known it was there.


Anonymous said...

I'm glad you saw it and didn't get bit.

Anonymous said...

deal. next time i see a snake crossing the road, i'll hit it so you can examine its stomach.

David Steen said...

"I'm glad you saw it and didn't get bit."

Me too. But the coral snake has such small mouth and narrow gape that they don't present much of a danger to somebody minding their own business.