By: John Hodges

Objectives

• Identify the 6 most common poisonous snakes in Texas.

• Identify the signs and symptoms of the snake bites.

• Know the treatment for the snake bites.

Poisonous Snakes in Texas• There are ten species of Rattlesnake in Texas.

Only three interact routinely with humans

• There are six poisonous snakes in Texas– Western Diamondback Rattlesnake– Massasauga Rattlesnake– Timber Rattlesnake– Cotton Mouth Water Moccasin– Copperheads – Coral Snakes

Western Diamondback Rattler

Massasuga Rattler

Timber Rattler

Cotton Mouth Water Moccasin

Texas Coral Snake

Copperhead

Poisonous VS Non-poisonous

Non-poisonous snakes tend to look like the poisonous ones. This helps to protect the

non-poisonous snake.

Some examples from Texas:

Big bend milk snake

Mexican milk snake

Texas long nose snake

Texas lyre snake

Big bend Milk Snake Mexican Milk Snake

Coral Snake

Texas long nose snake

Texas Lyre Snake

Timber Rattlesnake

Western Diamondback Rattlesnake

Pit Vipers

Pit Vipers

• The name comes from the depression/pit in the maxillary bone. It sits between the nose and eye, but a little lower.

• The pit is believed to be a heat sensing organ that help the snake to detect it’s prey. Especially at night.

• It is believed that the pit also helps the snake to determine the amount of venom to release by how much heat the prey emits.

Elliptical pupil and Nostril

Pit

Pit Vipers

• Other identifiable characteristics:– vertical elliptical pupils– Triangular head– Most have “rattles”. One rattle per skin slough.

Rattles are to let you know you are in the vicinity of the snake. Rattle increases the closer you get to the snake.

– Two part tongue used for smell.

Pit Vipers

• The fangs of a pit viper are at the front of the jaw and are “hinged”. They fold backward against the roof of the mouth when not in use.

• The venom apparatus consists of a gland and hollow duct connected to the fangs.

• Pit vipers are most active between April and October.

• The venom is composed of hydrolytic enzymes and proteins designed to immobilize, kill and digest its prey.– Hydrolytic enzymes cause the red blood cells to

break down and affect the clotting mechanism of the blood, leading to necrosis and infarction of the tissue.

• Depending on the amount of venom injected, the venom can cause various toxic effects on the blood and other tissues.

Pit Vipers

Pit Vipers

• Venom can cause:– Hemolysis (breakdown of red blood cells and the

release of hemoglobin)– Intravascular coagulation– Convulsions– Acute renal failure– secondary bleeding can lead to hypovolemic

shock from coagulation defects and massive swelling.

Pit Vipers

• The snake can release any quantity of venom on any given strike. From none to the entire amount in the glands.

• Bites are usually on the legs or hands

• 20% of bites do not result in envenomation

• Pit viper bites have a distinctive two puncture holes with teeth abrasions.

Pit Vipers

• Pit vipers strike is lightning fast. Depending on the snake, the striking stance is different.

Pit Viper

• A severe bite form a pit viper can result in death from shock within 30 minutes– Most deaths occur from 6 to 30 hours after the

bite.

Pit Vipers

• Signs and Symptoms

• Fang Marks

• Swelling and pain at bite marks

• Oozing at bite

• Weakness, dizziness, or fainting

• Sweating and/or chills

• Thirst

• Nausea and Vomiting

• Diarrhea

• Tachycardia and hypotension

• Bloody urine and GI hemorrhage (late)

• Shallow Resp. progressing to failure

• Numbness and tingling around face and head (classic)

• Metallic taste in mouth

Pit Viper• Management

– Bring the snake to the hospital for identification DEAD. If possible or practical. Do not delay patient care to find the snake.

– ABC’s– EKG and IV– Immobilize bite – Lymphatic constricting bands– DO NOT USE ICE PACKS OR COLD PACK– In hospital - antivenom

Western Diamondback Rattlesnake

• Holds first place for most serious bites and highest fatalities in US.

• Average three to four feet in length, but have been know to grow to seven feet in length.

• Has a rattle which grows longer after each molt. Used to scare off intruders.

• Life span of about 15 years.

• Young are born with fangs and venom intact.

Western Diamondback Rattlesnake

• They are aggressive and excitable.• When alarmed they make a sound that

resembles a sudden burst of steam.• Hibernate in groups.• Hibernation in colder habitats are in holes

and tunnels of burrowing mammals.• Hibernation in warmer habitats are in rock

crevices and they hibernate in small groups.

Western Diamondback Rattlesnake

• They are nocturnal hunters.• They inhabit area such as dry, rocky, shrub-

covered terrain and conceal themselves inside crevices in the rocks.

• They will stand their ground when disturbed.• In a defensive posture they will raise their

head and loop the neck up high above it’s coils. This gives it a better striking position.

Western Diamondback Rattlesnake

• Lidless eyes that are protected by an outer skin.

• Has alternating bands of black and white that are of equal width in the tail.

• Brown diamond shaped markings are found along the middle of the rattler’s back.

Western Diamondback Rattlesnake - Variations

Albino Western Diamondback Rattlesnake

Melanistic Western Diamondback Rattlesnake

Massasauga Rattlesnake

• Average about 3 feet in length• Life span of about 14 years• Young are born with fangs and venom intact.• Fangs are about 5.0 to 5.9 mm in length.• Eyes have an elliptical pupil.• They are nocturnal in the hot months • Often seen basking on rocks.

Massasauga Rattlesnake

• Hibernation sites include rock crevices, rodent and crayfish burrows, old stumps, and rotten logs.

• Can survive a freezing body temperature for short periods of time without harm.

• Reports describe the Massasauga as sluggish and mild-mannered or very alert and irritable. All should be considered Extremely dangerous.

Massasauga Rattlesnake

• They will rattle their tail and strike if someone comes to close.

• They inhabit areas such as swamps, marshes, bogs, wetlands and wet prairies.

• They are also found in open sunny areas with elevated basking areas.

Massasauga Rattlesnake

• Grey to brown bodies with dark blotches down their back.

• Tail is ringed with alternating dark or light bands

Timber Rattlesnake• Average about 3 to 6 feet in length.

• Maximum life span of 30 years.

• Newborns are equipped with 2.6mm long fangs and venom intact.

• Adults have fangs 8.7 - 10.4 mm in length. They can replace fangs if lost or broken.

• They will hibernate in large groups.

• They may migrate for miles to specific hibernation locations.

Timber Rattlesnake

• Their dens are rock crevices in south facing slopes, mammal burrows and large hollow logs.

• They will retreat if disturbed. If cornered, they will form a loose coil with head raised and strike when the intruder is close. They will coil and strike with the rattle active the whole time.

Timber Rattlesnakes

• They are mild tempered compared to other rattlesnakes, but are still extremely dangerous.

• They are ambush predators that “sit and wait” for prey.

Timber Rattlesnake• The head is yellow and unmarked.

• Tail is always black.

• Belly is white gray with dark flecks.

• Has black or brown crossbands on a yellow or brown body.

Cottonmouth Water Moccasin

• Average length up to six feet.• Young are born with fangs and venom intact.• Stubby, muscular snake.• They rarely stray from water.• Moccasins can bite underwater, However,

they cannot strike underwater due to the water resistance..

Cottonmouth Water Moccasin• Most commonly found in marshes, swamps,

ponds, shallow lakes, ditches and canals, slow moving streams.

• They are very defensive and aggressive. They will stand their ground or even approach its aggressor.

• They will readily vibrate their tail when provoked and can make make an impressive “rattling” sound against leaves, water or solid objects.

Cottonmouth Water moccasin

• Their mouths will snap shut when touched like a trap. Hence, the nickname “Trapjaw”.

• Their powerful jaws support the snake latching on, rather than a strike and release, when biting.

Cottonmouth Water Moccasin

• Body is brown, olive or blackish in color.

• With a lighter belly and crossbands extending all the way down around and across its belly.

• They have a dark stripe on their cheek that runs through the eye.

Copperhead• Average about 2 - 4.5 feet in length.

• Life span of about 29 years

• Young are born with fangs and venom intact.

• Adult fangs are about 1.1 to 7.2 mm in length.

• They are nocturnal during the hot months.

• They bask during the day in spring and fall.

• They may climb into low bushes or trees to hunt or bask

Copperhead

• Eyes have an elliptical pupil.• They migrate to communal hibernation dens.• Hibernation sites include: caves, gravel banks,

old stone walls, building foundations, animal burrows, logs, stumps and sawdust piles that extend well below the frost line.

• They have no affinity for water,but do favor damp habitats.

Copperhead

• Fatalities from the bite are almost nonexistent, but they should be considered extremely dangerous.

• They will lie motionless in a coil when approached.

• They are often touched and stepped on due to the camouflage pattern.

• When touched they will strike or flee or may remain quiet.

Copperhead

• If handled, they will spray a musk. It smells of cucumbers.

• Adults are ambush predators

• Young actively stalk their prey.

Copperhead• Copperhead are without a rattle.

• The body is copper, orange, or pink tinged with brown to reddish-brown saddle shaped bands.

• Bands widen along the sides of the body and narrow at the center. (hourglass pattern)

Coral Snake

• The coral snake in contrast to the pit vipers, has round pupils and small fixed fangs located near the anterior end of the maxilla

• Has three-color pattern with red, yellow and black along with a black snout.

• Many non-poisonous snakes in the US mimic the appearance of the coral snake.

• “Red on Yellow will kill a fellow, Red on Black will venom lack.”

Big bend Milk Snake

Mexican Milk Snake

Coral Snake

Texas long

nose Snake

Coral Snake

• Coral snakes are shy and docile and they seldom bite unless threatened. They will rarely bite when handled.

• Most common bitten area is the finger, toes or folds of skin, due to small mouth and fangs.

• Coral snakes have to chew rather that strike it’s prey.

Coral Snake

• The venom is a neurotoxin and blocks the acetylcholine receptor sites.

• It affects the nervous tissues.

• The bite will generate little to no pain.

• There is no edema or necrosis of the tissue.

• Systemic effects may not appear until 12 - 24 hours after the bite.

Coral Snake• Signs and Symptoms• Slurred speech and

excessive salivation• Dilated pupils, double

vision and drooping eyelids

• Localized numbness, weakness and drowsiness

• Nausea and vomiting

• Flaccid paralysis of tongue and larynx

• Loss of consciousness• Seizures• Hypotension• Abdominal pain• Death from respiratory

failure• Late signs arise from the

nervous system dysfunction.

Coral Snake

• Management– Supportive only– Wash wound with copious amounts of sterile

water.– Apply constricting bands between bite and

heart. Lymphatic bands only, not venous or arterial. No tighter than a watch band.

– In hospital - antivenom

Questions?????