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TERMINOLOGY:
VENOMOUS: This means that something is harmful when injected into the body. Our dangerous snakes (Cottonmouths, Copperheads, Canebrake rattlesnakes, Pigmy Rattlesnakes, and Coral Snakes) are venomous. So are Black Widow Spiders, wasps, stinging caterpillars, etc.
POISONOUS: This means that something is harmful when swallowed. Snake venom is not poisonous to humans. A person can drink a glass full without harm (unless he/she has cavities or a stomach ulcer!).
COTTONMOUTH: This word always refers to the venomous snake.
WATER MOCCASIN: This term usually refers to the venomous snake, but some people use it for the non-venomous species. If we use this term, it should only be for the venomous cottonmouth.
WATER SNAKE: Water snakes are never venomous. They include the local Diamondback Water Snake, Broad-banded Water Snake, Yellowbelly Water Snake, and Green Water Snake.
GROUND RATTLER: This is a common name for the venomous Pigmy Rattler, which does have very small rattles and is dark with dark spots.
WHAT KINDS OF VENOMOUS SNAKES DO WE HAVE IN AMERICA'S WETLAND?
We may encounter Cottonmouths (see below), Copperheads (light tan with dark tan hour glass markings), Canebrake Rattlesnakes (from 12" to 6 ft., large rattles, black markings across a tan back, a copper stripe down the middle of the back), and Pigmy Rattlesnakes (up to 15" long, gray with many dark, rather large spots and a small rattle). We do not have Coral Snakes on this side of Lake Pontchartrain, but they are not uncommon in St. Tammany and nearby regions.
WHAT ABOUT THEIR VENOMS?
Coral snakes are in the cobra family and their venom kills by attacking the nervous system; victims have great difficulty breathing. The rest are pit vipers, and their venom causes the blood system to break down and it causes parts of the body to stop receiving blood flow (which means no oxygen, so the tissues dies, causing something like gangrene).
WHY DO THESE SNAKES HAVE VENOM AND DO THEY ALWAYS INJECT VENOM WHEN THEY BITE?
The main purpose of snake venom is to allow the snake to get and digest food. These snakes are “sit and wait” hunters. That is, they sit near a place where their preferred food moves, and they lash out and bite their prey when it moves by. They then follow it and swallow it whole. Since they swallow it whole, imagine if a large rat was in the stomach being digested from the outside, and it would take several days to be digested. The rate would start to decompose during that time and make the snake very ill. But, since the snake venom is a digestive compound, the prey is digested from the outside by the snakes stomach and from the inside by the snakes injected venom. They system seems to work well for the snakes.
They can inject venom if they want to. However, the venom is there for them to get a meal, and they know you are not a potential meal. If they bite you it will be in self defense. As many as 30% of all pit viper bites inject no venom. Of the other 70%, the range may be from just a very little to a major deposit. The more agitated the snake, the more likely it is to give a full-load bite (such as if you are aggravating it); also, a surprised snake may deliver venom on reflex.
ARE THEIR BABIES VENOMOUS?
All the pit vipers give live birth. While the babies are still in their birth sack, they can bite and inject venom. Though they probably wouldn’t kill an adult, they would cause serious illness. Drop for drop, the babies’ venom is more powerful than the adults, but they don’t have as much to inject.
WHICH OF THE SPECIES THAT WE HAVE ARE THE MOST DANGEROUS?
Cottonmouths are usually considered the most dangerous. This is because they have a bad temper and will readily bite. Their venom is very nasty in that it often causes symptoms like gangrene, causing tissue to rot or have to be amputated. These are very nasty bites.
Canebrake Rattlers have a less dangerous venom, but they may (because of their size) have a lot more venom to inject. A large Canebrake can give a lethal bite! Though very large, these rattlers rely heavily on protective coloration and are generally not prone to bite. But if they do, they can deliver a terrible pay-load.
Pigmy Rattlers have a less powerful venom and would rarely be able to kill an adult, but children must be very careful. Regardless, the bite can put anyone in a hospital for several days. Like the Canebrake, these fellows are not quick biters, but they will if provoked.
Copperheads’ venom is possibly the least potent drop for drop, but large specimens can inject a good quantity of venom and must be given due respect. Typically a copperhead will not bite unless touched; they rely heavily on protective coloration. But don’t trust them! When they do bite, they might bite several times before stopping.
HOW CAN WE TELL THE DIFFERENCE BETWEEN A COTTONMOUTH AND A WATER SNAKE?
There are some simple ways to tell these snakes apart easily, even from as far away as on board a boat or on a dock.
- Cottonmouths are dark, rather stout snakes. The only water snake that is as dark as a cottonmouth is the Broad-banded Water Snake. The rest are much lighter and/or have real obvious patterns that identify them. If you see a very dark snake coiled on a log or limb, then look for the following:
- Cottonmouths have bands around the body that have jagged edges. When young, they are a rusty brown; as an adult they get very dark. When wet, the pattern is very obvious. When dry, they get very dull and dark and no pattern may be present. The Broad-banded Water Snake is similar, but it always has some light bands across the back.
- Cottonmouths usually have one or two light stripes on the side of the head, running from the eye to the back of the head. Water Snakes never have this feature.
- Cottonmouths have a flat surface on the top of the head (see the preserved specimens on the boats). The front part of the head (from the eye to the tip of the nose), the side of the head is rather flat; at the top, there is a sharp angle that makes the flat surface. The Water Snake has a rounded head, with no sharp angle between the side and the top of the head.
- Cottonmouths often tilt their heads back (nose toward the sky) and open their mouths when approached. Water Snakes never do this, though they may keep the head low and strike.
- If in the water and not moving, Cottonmouths usually float on the surface, while Water Snakes always have the body underwater. The same is true for swimming. If you pull up to a Cottonmouth on the surface, it may float, cock its head back, and open its mouth in threat. Water Snakes will always dive to get away. However, Cottonmouths do often dive, also.
- Cottonmouths have cat-eyes (elliptical pupils), though this is often hard to see in preserved (dead) specimens. In daylight, the pupil is a narrow dark slit; in the dark it gets very round (it opens to allow more light in so it can see in the dark). Water Snakes have a round pupil all the time. You can see this in the preserved specimens, but it is hard to see on a live specimen, only because you have to get so close.
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