Snakes of Missouri

In Missouri, any snake found near the water or swimming in it is presumed to be a venomous cottonmouth. The snake that usually gets killed by snake-fearing humans in this scenario is frequently not a cottonmouth. Cottonmouths do, indeed, reside in Missouri and they live along streams and remote portions of some of the lakes in this part of the state; but they don’t have the range or commonality that often is attributed to them. Now that it’s warming up, cottonmouths will be coming out of their winter dormancy. So will all the humans who like to frequent streams and lakes. So, it’s a good time to review the facts – and a few fallacies – that surround cottonmouths. Let’s start with the facts:

Cottonmouths are highly venomous snakes that should be treated with the utmost respect by humans. Their preferred habitat areas are along creeks and small rivers. The northern cottonmouth – the type of cottonmouth found in Missouri – is a heavy-bodied snake that ranges in color from dark olive to almost black in coloration. This thick-bodied snake typically grows to between three and four feet in length and can reach nearly two pounds in weight. It has cross- bands across its body, but these markings are often indistinct due to the snake’s overall dark color. The belly is cream-colored and heavily mottled. The snake’s most noticeable characteristic is the one that gave it its name: As a defensive measure, cottonmouths hold their mouths open in a wide gape; showing a white interior.

Cottonmouths are primarily nocturnal. They feed on fish, frogs, lizards, rodents, small birds and other snakes. Its venom has a higher toxicity, which makes it an effective hunter. Along with these truths are some fallacies that are often associated with cottonmouths. Perhaps the biggest mistake many people make is the assumption that any dark snake seen in or near the water is a cottonmouth. The truth is that all snakes can swim and many of Missouri’s snake species can frequently be found near water. So, just because you see a dark snake in the water, it doesn’t mean it’s a cottonmouth. People also need to remember that cottonmouths aren’t found state-wide in Missouri – they’re only found in the southern part of the state.

Contrary to what some people claim, cottonmouths do not go out of their way to “ambush” humans. The truth behind this belief has to do more with a cottonmouth’s defensive mannerism than with wanton aggression. Unlike many other species of snakes, cottonmouths often will not back down when they are agitated or feel threatened. This stems from the snake’s instinctual knowledge that it possesses potent venom. This creates a potential scenario of humans unknowingly getting too near a snake that’s willing to stand its ground and is good at concealment. This, in turn, can lead to situations where people feel they were aggressively “attacked” out of nowhere by a cottonmouth when, in truth, what happened was a human got too near a partially concealed snake that had no intention of fleeing.

If one is bitten by a cottonmouth, medical attention should be sought immediately. As is the case with avoiding other venomous snakes in the wild, the key to avoiding cottonmouths is awareness. When walking along a stream or swamp, always be on the lookout for snakes and always check before you step over a rock or a log or into thick vegetation. Information about cottonmouths and other snakes of Missouri can also be found at mdc.mo.gov.

Francis Skalicky is the media specialist for the Missouri Department of Conservation’s

Southwest Region. For more information about conservation issues, call 417-895-6880.