Notice the chain-like pattern on the back of the Diamond backed watersnake to the left. Then check out the creamy-white coloring under the chin of the Western cottonmouth on the right. (MDC photos by Candice Davis)
Seeing a snake in the wild is an exhilarating experience. For some, it may be a little too much of an adventure. But knowing how to identify what snake species you may see is a valuable tool and knowing how to respect wildlife is equally valuable. A wild snake, like any wild animal, is unpredictable and can be dangerous if it feels threatened. On a recent canoe trip through a section of the Mingo National Wildlife Refuge, I had the chance to not only identify two snakes but also to show them respect on their own turf.
To the untrained eye, the two didn't look much different. But if you know what to look for you will see that one of these snakes is venomous, one is not.
The first encounter was with a lazy, quite large snake with dark bands on his back that seemed to be linked like a chain. He had a dull yellow belly that had some irregular dark brown spots. Our canoe nearly bumped the log he rested on and he didn't even glance over to see who the offender might be. We maneuvered around the log -- with my camera snapping along trying to get a good snapshot without disturbing his nap.
The second snake we saw was not at all lazy. He must've seen us coming because he was racing along the top of the water towards the bank. He barely seemed to move his body at all as he skimmed easily across the swamp to avoid visiting with us. When he reached a log that stuck out from the bank, he slithered alongside it, as if hoping to blend in with it. Just as we passed by, he reached the corner of the bank and turned to face us to make sure we weren't coming any closer. I got the message he was prepared to stand his ground if we encroached further on his territory. So of course we didn't.
This serious fellow had the same dark black color as the first, but his back was nearly solid black with just a few small olive brown markings. The creamy white color along his mouth and chin was a dead giveaway that he was a Western cottonmouth.
He was also easy to identify from behind, though, because his head was dramatically wider than his back. That triangular snake-head is a sure sign of a venomous snake, if you know what to look for. If a snake's nose comes to a point, that doesn't mean his head is triangularly shaped. The venomous snake will not only have a pointy nose, but his jaw line will jut out from the rest of his body making his head shape a very recognizable triangle. The University of Massachusetts has a very nice illustration of this at http://www.umass.edu/nrec/snake_pit/pages/heads.html.
You can also identify a venomous snake by the elliptical shape of his pupils, but this is a better tool when identifying from a photo -- not in a live situation.
The trip wasn't over when we left the refuge. I was eager to take my photos and compare them against Tom Johnson's guidebook "The Amphibians and Reptiles of Missouri". The first large, lazy sleeper was a Diamond-backed water snake, which the book says is Missouri's largest species of water snake. These snakes range from 30 to 48 inches in our state, although the record length for this species is 63 inches (Conant and Collins 1991). Johnson notes that this snake could be misidentified as the Western cottonmouth, but knowing to look for that chainlike dark pattern on the back will help to identify him as the Diamond-backed water snake.
The Diamond-backed water snake eats fish, especially slow-moving or dead fish, frogs, toads and salamanders. The Western cottonmouth is primarily a fish-eater but also eats frogs, other snakes, lizards and rodents.
Though our first reaction could be to scream or be afraid of these snakes, knowing to identify them - and most importantly -- knowing to give them their own space and respect in their home territory is key to enjoying a day in the wild without unnecessary fear.
A canoe trip is nice, but taking it further to learn from what you see is even better. We also saw a Great Blue Heron, a Belted Kingfisher, a Wild Turkey, and two Vultures that morning. But those are for other stories.