Cottonmouth Aggression

Western Cottonmouth  - Tom Spinker CC

We recently wrote about the death of a Northern Watersnake which was misidentified as a cottonmouth that was "coming after" a swimmer.  One of the most common snake myths that I hear is that cottonmouths (Water Moccasin) are aggressive and attack canoes, kayaks and people swimming and wading in our streams.  

Green area is our A. p. leucostoma- Wikipedia

There are three subspecies of cottonmouths, Agkistrodon piscivorus, in the US.  Our native Missouri species is A. piscivorus leucostoma (white-mouth).  They are mainly in Southeast Missouri sloughs and the rocky creeks of the Ozarks.  We haven't seen them on Bull Creek but I suspect they are here.

  MDC - Noppadol Paothong

A recent story by Francis Skalecky in the Springfield News-Leader addressed cottonmouths but I want to follow up on it. While they may be harder to intimidate, they are not out looking to waste their venom on humans, or kayaks for that matter. All of these are too big for a snake to swallow and once their venom is used, they can't subdue prey for several days while they restore the supply.

Research at the University of Georgia entitled Defensive Behavior of Cottonmouths Toward Humans tested their aggressiveness with three scenarios.

• First they stood closely beside the snake with a snakeproof boot touching its body.  Of 13 individual cottonmouths tested, four attempted to escape, five gave some form of defensive display, and none tried to bite, although one individual feigned a bite during a strike. Only two of the snakes performed more than one defensive display.
• Second scenario-  They stepped on the snake at midbody with enough force to restrain but not injure it.  Of the 22 that were stepped on either initially
  or secondarily, 15 gave defensive displays, including two that feigned bites.
  Nine of those stepped on were attempting to escape by crawling away and one bit the boot.
• Third Scenario-  They picked up the snake at midbody with a pair of
  1-m snake tongs (Whitney Tongs) with a grasping handle that was modified to resemble a human arm and hand. A leather glove was fitted over the end of the tongs, with one extension covered by the thumb and the other by the middle finger. Hence, the glove could be closed around the snake’s body. A padded shirt sleeve was used to cover the remainder of the rod up to the handle.  Each treatment was carried out for 20 sec, and the behavior of each snake was recorded. 
  Of the 36 individuals held in the "hand" for 20 seconds, only13 (36%) bit the artificial hand, striking near the point of contact with the snake’s
  body.

I would not suggest that you do any of the above maneuvers with any snake.  This is unquestionably a dangerous snake, one to be respected like any other animal that can hurt or kill you.  They just want to be left alone as do we.  A frequent question we hear is "Is it illegal to kill a snake?" so here is the answer in MDC Discover Nature.

Missouri's Wildlife Code Protects Snakes

Few Missourians realize that all snakes native to our state are protected. The Wildlife Code of Missouri treats snakes, lizards, and most turtles as nongame. This means that there is no open season on these animals, and it is technically unlawful to kill them. There is a realistic exception, however: when a venomous snake is in close association with people, which could result in someone being bitten. We hope that more people realize that snakes are interesting, valuable, and, for the most part, harmless. 
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From Lisa Berger, a mother Cottonmouths instructions to the snakelings:  "Use venom only if you are being crushed, or if you need to subdue food; otherwise bite gingerly, and inject accordingly."