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Thursday, September 2, 2010

Poisonous Snakes Of The Southwest

Rattlesnakes

Rattlesnakes are the most common poisonous snakes in New Mexico and throughout the Southwest. The primary way to distinguish a rattlesnake from other snakes is the presence of a rattle, a series of horny rings formed of keratin that scrape against each other in pulses to cause a rattling sound.

Some nonpoisonous snakes, such as bull snakes, coach-whips, and rat snakes, behave like rattlesnakes when confronted. This behavior may include hissing loudly or vibrating the tail. If the tail is in contact with dry leaves or grass, these snakes may be mistaken for rattlesnakes.

Most rattlesnakes have triangular or “spade-shaped” heads (wide at the back and attached to a narrow neck). Many other harmless snakes can flatten their heads when threatened and may look like rattlesnakes.

New Mexico has seven species of rattlesnakes that vary in size, color, and other characteristics. The color of a rattlesnake’s scales often matches the environment; brown, gray, green, red, pink, or yellow.


Rock Rattlesnake


The Rock Rattlesnake are found in isolated mountain ranges in Southern New Mexico. This snake may be found in pine-oak forests, but mostly inhabits mountains with rugged, rocky terrain. It is variable in color and may be brown-black, greenish, or gray.

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Western Diamondback

The Western Diamondback Rattlesnake is found throughout much of New Mexico, and is the species most often seen. It lives in flat plains and rocky canyons, from grassland deserts to pine-oak forests. The western diamondback is one of the largest of all rattlesnake species and the largest found in New Mexico (up to 6 ft long). Their color is most often gray-brown, although color often depends on the matching background color—many New Mexico snakes have a reddish to pinkish-gray color. This species has black and white rings on its tail, so it is commonly called the “coon-tail” rattlesnake.

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Western Prairie Rattlesnake

The Western (Prairie) Rattlesnake is distributed across New Mexico, much of the western U.S., and into Canada. In eastern New Mexico, it is often called “sand rattler” and lives in a variety of habitats, from grassland desert to pine-oak forest. This species is generally more active after dark, except at high altitudes. Western prairie rattlesnakes are often greenish-gray or pale brown, with a series of light-colored rings on the tail that darken with maturity.
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Mojave Rattlesnake

The Mojave Rattlesnake is found in extreme Southern New Mexico, although it is more common in southern California Nevada, Arizona and Texas and is more widely distributed in the Chihuahua Desert than the Mojave Desert. It lives in desert or low grassland habitats, often on flat terrain. The Mojave rattlesnake is often greenish-gray or olive green, with a white belly. Its venom is highly potent.
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Black-tailed Rattlesnake

The Black-tailed Rattlesnake is distributed in southwestern and central New Mexico. It lives mostly in rocky mountainous areas, and is found occasionally in lower desert habitats. It is often colored a greenish or steel gray (but can be sulphur yellow or rust), with a dark brown or black tail. Generally considered mild mannered, this rattlesnake can nonetheless be quick to rattle and raise its head. It has been seen several feet off the ground in trees.
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Massasauga

The Massasauga is distributed across southern, central, and eastern New Mexico where it occupies desert grassland, often in very sandy areas. This snake is relatively small (less than 4 ft long) and pale brown, and generally has pairs of spots on its head. Although not usually fatal to humans, bites from this species can be extremely painful.
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Ridged-nose Rattlesnake

The Ridged-nose Rattlesnake is listed by the U.S. Fish and Wildlife Service as a threatened species in New Mexico. It inhabits only a small part of the southwestern boot heel of the state, living in pine-oak woodlands, open grassy hillsides, and humid canyon bottoms. Its color is reddish brown, yellowish brown, or gray. Ridge-nose rattlesnakes are generally active day or night and tend to have a mild temperament.

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North American Sidewinder

The venomous Sidewinder is also called the "Horned Rattlesnake." It is unique because of its sideways form of locomotion with its body moving in an S-shaped curve.

Range:

Mojave and Sonoran deserts of southeastern California, western Arizona, southern Nevada and extreme southwestern Utah to Mexico.
Habitat

This Sidewinder is light in color- tan, cream, pink, gray or sandy, with darker patches on its back of gray, yellow or tan. Mature adults grow 18 to 32 inches in length. It also has a dark eye strip extending back along its head.

The Sidewinder has rough, keeled scales, which aid in its unique sidewinding locomotion. Its supraoculars (triangular projections over each eye) are pointed and upturned giving them a horn-like appearance -thus its nickname, the Horned Rattlesnake.
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Arizona Coral Snake (Sonoran Coral Snake)
(photo by Dr. Brendan P. O'Connor)

Coral Snake

The Arizona coral snake (also called the Sonoran Coral Snake) is found in extreme southwest Catron County and western Hidalgo and Grant counties. Although coral snakes rarely bite, their venom is highly poisonous and they should not be handled. The Arizona coral snake has a black nose and is brightly colored with broad alternating rings of red and black, separated by narrower rings of white or yellow. These markings encircle the body, although they are less bright on the belly.

In New Mexico, other snakes with similar markings are the New Mexico milk snake, Arizona mountain king snake, and the long-nosed snake. The narrower red bands are bordered by black on the New Mexico milk snake and Arizona mountain king snake, while the Arizona coral snake has broad red bands with yellow borders. The long-nosed snake is pale compared to the Arizona coral snake, with stripes that do not extend around the body and white spots on the side of the snake’s black bands.

An easy way to determine whether a red, yellow, and black snake is a coral snake is to remember that red touches yellow on a coral snake, and red touches black on non-poisonous species.
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American Copperhead

Like all pit vipers, the American Copperhead is generally an ambush predator: it takes up a promising position and waits for suitable prey to arrive. One exception to ambush foraging occurs when copperheads feed on insects such as caterpillars and freshly molted cicadas. In the southern United States, they are nocturnal during the hot summer months, but are commonly active during the day during the spring and fall.

Like most North American viperids, these snakes prefer to avoid humans and, given the opportunity, will leave the area without biting. However, unlike other viperids they will often "freeze" instead of slithering away, and as a result many bites occur from people unknowingly stepping on or near them.

This tendency to freeze likely evolved because of the extreme effectiveness of their camouflage. When lying on dead leaves or red clay they can be almost impossible to notice. They will frequently stay still even when approached closely, and will generally strike only if physical contact is made.
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Cottonmouth Snake
The Cottonmouth is found in the eastern United States from Virginia, south through the Florida peninsula and west to Arkansas, eastern and southern Oklahoma, and east and central Texas. A few records exist of the species being found along the Rio Grande in Texas, but these are thought to represent disjunct populations, now possibly eradicated.

The broad head is distinct from the neck, the snout blunt in profile with the rim of the top of the head extending forwards slightly further than the mouth. The body has a heavy build and a tail that is moderately long and slender.

Though the majority of specimens are almost or even totally black, (with the exception of head and facial markings) the color pattern may consist of a brown, gray, tan, yellowish olive or blackish ground color, which is overlaid with a series of 10-17 crossbands that are dark brown to almost black.

These crossbands, which usually have black edges, are sometimes broken along the dorsal midline to form a series of staggered half bands on either side of the body. These crossbands are visibly lighter in the center, almost matching the ground color, often contain irregular dark markings, and extend well down onto the ventral scales.

The dorsal banding pattern fades with age, so that older individuals are an almost uniform olive brown, grayish brown or black. The belly is white, yellowish white or tan, marked with dark spots, and becomes darker posteriorly.


Stay Prepared! Stay Alive!

Charlie

Snake Talk




Venomous Snakes and Lizards:

If you fear snakes, it is probably because you are unfamiliar with them or you have wrong information about them. There is no need for you to fear snakes if you know:

• Their habits.
• How to identify the dangerous kinds
• Precautions to take to prevent snakebite.
• What actions to take in case of snakebite.

For a man wearing shoes and trousers and living in a camp, the danger of being bitten by a venomous snake is small compared to the hazards of malaria, cholera, dysentery, or other diseases.

Nearly all snakes avoid man if possible. A few—the king cobra of Southeast Asia, the bushmaster and tropical rattlesnake of South America, and the mamba of Africa—may aggressively attack man, but even these snakes do so only occasionally. Most snakes get out of the way and are seldom seen.

WAYS TO AVOID SNAKEBITE:

1. Snakes are widely distributed. They are found in all tropical, subtropical, and most temperate regions. Some species of snakes have specialized glands that contain a toxic venom, and long, hollow fangs to inject their venom.

2. Although venomous snakes use their venom to secure food, they also use it for self-defense. Human accidents occur when you don't see or hear the snake, when you step on them, or when you walk too close to them.

3. Follow these simple rules to reduce the chance of accidental snakebite:

• Don't sleep next to brush, tall grass, large boulders, or trees. They provide hiding places for snakes. Place your sleeping bag in a clearing. Use mosquito netting tucked well under the bag. This netting should provide a good barrier.

• Don't put your hands into dark places, such as rock crevices, heavy brush, or hollow logs, without first investigating.

• Don't step over a fallen tree. Step on the log and look to see if there is a snake resting on the other side.

• Don't walk through heavy brush or tall grass without looking down. Look where you are walking.

• Don't pick up any snake unless you are absolutely positive it is not venomous.

• Don't pick up freshly killed snakes without first severing the head. The nervous system may still be active and a dead snake can deliver a bite.

SNAKE GROUPS:

Snakes dangerous to man usually fall into two groups:

Proteroglypha- Fixed Fangs; usually dominate neurotoxic
Solenoglypha- Folded Fangs; usually dominate hemotoxic

VENOM:

The fixed-fang snakes (proteroglypha) usually have neurotoxic venoms. These venoms affect the nervous system, making the victim unable to breathe.

The folded-fang snakes (solenoglypha) usually have hemotoxic venoms. These venoms affect the circulatory system, destroying blood cells, damaging skin tissues, and causing internal hemorrhaging.

Remember, however, that most venomous snakes have both neurotoxic and hemotoxic venom. Usually one type of venom in the snake is dominant and the other is weak.

No single characteristic distinguishes a venomous snake from a harmless one except the presence of poison fangs and glands. Only in dead specimens can you determine the presence of these fangs and glands without danger.

There are about twenty-seven species of rattlesnakes in the United States and Mexico. They vary in color and may or may not have spots or blotches. Some are small but others, such as the diamondbacks, may grow to 2.5 meters (8 feet) long.

LIZARDS:

There is little to fear from lizards as long as you follow the same precautions as for avoiding snakebite. There are only two poisonous lizards: the Gila monster and the Mexican beaded lizard. The venom of both these lizards is neurotoxic. The two lizards are in the same family, and both are slow moving with a docile nature.





The Gila monster is a species of venomous lizard native to the southwestern United States and northern Mexico (but not Baja California). A heavy, slow-moving lizard, up to 2 feet long, the Gila monster is the only venomous lizard native to the United States and one of only two known species of venomous lizards in North America, the other being its close relative, the Mexican beaded lizard.

Though the Gila monster is venomous, its sluggish nature means that it represents little threat to humans. However, it has earned a fearsome reputation and is sometimes killed by hikers and homeowners despite being protected by state law in Arizona and Nevada.

Venom is produced in modified salivary glands in the Gila monster's lower jaw, unlike snakes, whose venom is produced in the upper jaw. The Gila monster lacks the musculature to forcibly inject the venom; instead, the venom is propelled from the gland to the tooth by chewing. Capillary action brings the venom out of the tooth and into the victim. The teeth are loosely anchored, which allows them to be broken off and replaced throughout life.
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Mexican Beaded Lizard

Adult beaded lizards range from 24 inches to 36 inches in length. It is substantially larger than the Gila monster, which only reaches lengths of 12 inches to 16 inches. Although males are slightly larger than females, the animals are not sexually dimorphic.

Both males and females are stocky with broad heads, although the males tend to be broader. The beaded lizard's scales are small, bead-like and non-overlapping. Except for the underside of the animal, the majority of its scales are underlaid with bony osteoderms.

Their base color is black and marked with varying amounts of yellow spots or bands, with the exception of H. h. alvarezi, which tends to be all black in color.

The beaded lizard has a short tail which is used to store fat so the animal can survive during months of estivation. Unlike many other lizards, this tail does not autotomize and cannot grow back if broken. The beaded lizard has a forked black tongue which it uses to smell, with the help of a Jacobson's organ; it sticks its tongue out to gather scents and touches it to the opening of the organ when the tongue is retracted.

The venom glands of the beaded lizard are modified salivary glands located in the animal's lower jaw. Each gland has a separate duct leading to the base of its grooved teeth. When biting, the beaded lizard hangs on its victim and chews in order to get its venomous saliva into the wound. Although its jaw grip is strong its unsocketed teeth are easily broken off at their bases.

The beaded lizard's venom is a weak hemotoxin and although human deaths are rare, it can cause respiratory failure. It consists of a number of components, including L-amino acid oxidase, hyaluronidase, phospholipase A, serotonin, and highly active kallikreins that release vasoactive kinins. The venom contains no enzymes that significantly affect coagulation. Almost all documented bites (eight in the past 100 years) have resulted from prodding captive animals with a finger or bare foot.
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The komodo dragon (Varanus komodoensis), although not poisonous, can be dangerous due to its large size. These lizards can reach lengths of 3 meters (10 feet) and weigh over 115 kilograms (253 pounds). Do not try to capture this lizard.

Note: Snakes make a good survival meal. (But not worth getting injured over if you don't know what you are doing.)

Stay Prepared! Stay Alive!

Charlie

Figure 4 Trigger





Figure 4 Instructions


The figure 4 is a trigger used to drop a weight onto a prey and crush it. The type of weight used may vary, but it should be heavy enough to kill or incapacitate the prey immediately.

Construct the figure 4 using three notched sticks. These notches hold the sticks together in a figure 4 pattern when under tension. Practice making this trigger before-hand; it requires close tolerances and precise angles in its construction.

The wood used in the demonstration is the stalk from the Yucca Plant.

The deadfall material can be a box trap, a large flat stone or a log. Always remember to take your snares and traps apart when they are no longer needed so that unwanted game are not trapped needlessly.

Stay Prepared! Stay Alive!

Charlie