Snakebites
Snakebites
Poisonous and nonpoisonous snakes are widely distributed throughout North
America. Ninety percent of snakebites in dogs involve the head and legs.
In the United States there are four types of poisonous snakes: cottonmouths (also called water moccasins), rattlesnakes, copperheads, and coral
snakes. The diagnosis of poisonous snakebite is made by the appearance of the
bite, the behavior of the animal, and your identification of the species of
snake.
In general, bites of nonpoisonous snakes do not cause swelling or pain.
They show teeth marks in the shape of a horseshoe, but no fang marks.
PIT VIPERS (RATTLESNAKES, COTTONMOUTHS, AND COPPERHEADS)
You can identify these species by their large size (4 to 8 feet, 1.2 to 2.4 m,
long), triangular heads, pits below and between the eyes, elliptical pupils,
rough scales, and the presence of retractable fangs in the upper jaw.
The bite: You may see one or two bleeding puncture wounds in the skin;
these are fang marks. These marks may not be visible because of the dog’s
coat. The pain is immediate and severe. The tissues are swollen and discolored due to bleeding at the site of the bite.
Note that 25 percent of poisonous snakebites lack venom and thus do not
produce a local reaction. While absence of local swelling and pain is a good
sign, it does not guarantee the dog won’t become sick. Severe venom poisoning has been known to occur without a local reaction.
The dog’s behavior: Signs of envenomation may take several hours to
appear because of variables such as time of the year, species of the snake, toxicity of the venom, amount injected, location of the bite, and size and health
of the dog. The amount of venom injected bears no relationship to the size of
40 • DOG OWNER’S HOME VETERINARY HANDBOOK
the snake. Signs of venom poisoning include extreme restlessness, panting,
drooling, vomiting, diarrhea, uncoordinated gait, respiratory depression,
shock, and sometimes death.
CORAL SNAKES
Identify this snake by its rather small size (less than 3 feet, .9 m, long), small
head with black nose, and brightly colored alternating bands (red, yellow, and
black) fully encircling the body. The fangs in the upper jaw are not retractable.
The bite: The puncture wounds from a bite are small and the pain is mild.
There is little local reaction.
EMERGENCIES • 41
Pit
Fangs
Elliptical Pupil Round Pupil
Upper Jaw
Lower Jaw
Rattle
Single Row of Plates
Double Row of Plates
POISONOUS NONPOISONOUS
BITE
MARKS
Compare the characteristics of pit vipers and nonpoisonous snakes. Note the elliptical pupil, pit below the eye, large fangs, characteristic bite, and single row of subcaudal plates on the belly of the pit viper.
The dog’s behavior: Coral snake venom is neurotoxic, meaning it affects
the nerves and causes weakness and paralysis. Signs may be delayed for several
hours. They include muscle twitching, pinpoint pupils, weakness, difficulty
swallowing, shock, and collapse. Death is by respiratory paralysis.
TREATING SNAKEBITES
First identify the snake and look at the bite. If the snake is not poisonous, clean
and dress the wound as described in the section on Wounds (on this page). If it
appears the dog has been bitten by a poisonous snake, proceed at once to the veterinary hospital. (If the snake has been killed, take it with you for identification.
If not, try to describe it as completely as you can.) Some specific precautions:
• Keep the dog quiet. Venom spreads rapidly. Excitement, exercise, and
struggling increase the rate of absorption. If possible, carry the dog.
• Do not wash the wound, as this increases venom absorption.
• Do not apply ice, as this does not slow absorption and can damage tissue.
• Do not make cuts over the wound and/or attempt to suck out the
venom. This is never successful and you could absorb venom.
• Be aware that the snake’s fangs may be venomous for up to two hours
after it dies, even if you have cut off the head.
Veterinary treatment involves respiratory and circulatory support, antihistamines, intravenous fluids, and species-specific antivenin. The earlier the
antivenin is given, the better the results. Because signs of envenomation are
often delayed, all dogs who have been bitten by a poisonous snake—even
those who don’t show signs—should be hospitalized and observed for 24 hours.
If you live in an area where your dog is likely to come in contact with poisonous snakes, you may choose to take him through sensitization training. A skilled
professional will use an electric collar to train your dog to fear and avoid snakes.
Poisonous and nonpoisonous snakes are widely distributed throughout North
America. Ninety percent of snakebites in dogs involve the head and legs.
In the United States there are four types of poisonous snakes: cottonmouths (also called water moccasins), rattlesnakes, copperheads, and coral
snakes. The diagnosis of poisonous snakebite is made by the appearance of the
bite, the behavior of the animal, and your identification of the species of
snake.
In general, bites of nonpoisonous snakes do not cause swelling or pain.
They show teeth marks in the shape of a horseshoe, but no fang marks.
PIT VIPERS (RATTLESNAKES, COTTONMOUTHS, AND COPPERHEADS)
You can identify these species by their large size (4 to 8 feet, 1.2 to 2.4 m,
long), triangular heads, pits below and between the eyes, elliptical pupils,
rough scales, and the presence of retractable fangs in the upper jaw.
The bite: You may see one or two bleeding puncture wounds in the skin;
these are fang marks. These marks may not be visible because of the dog’s
coat. The pain is immediate and severe. The tissues are swollen and discolored due to bleeding at the site of the bite.
Note that 25 percent of poisonous snakebites lack venom and thus do not
produce a local reaction. While absence of local swelling and pain is a good
sign, it does not guarantee the dog won’t become sick. Severe venom poisoning has been known to occur without a local reaction.
The dog’s behavior: Signs of envenomation may take several hours to
appear because of variables such as time of the year, species of the snake, toxicity of the venom, amount injected, location of the bite, and size and health
of the dog. The amount of venom injected bears no relationship to the size of
40 • DOG OWNER’S HOME VETERINARY HANDBOOK
the snake. Signs of venom poisoning include extreme restlessness, panting,
drooling, vomiting, diarrhea, uncoordinated gait, respiratory depression,
shock, and sometimes death.
CORAL SNAKES
Identify this snake by its rather small size (less than 3 feet, .9 m, long), small
head with black nose, and brightly colored alternating bands (red, yellow, and
black) fully encircling the body. The fangs in the upper jaw are not retractable.
The bite: The puncture wounds from a bite are small and the pain is mild.
There is little local reaction.
EMERGENCIES • 41
Pit
Fangs
Elliptical Pupil Round Pupil
Upper Jaw
Lower Jaw
Rattle
Single Row of Plates
Double Row of Plates
POISONOUS NONPOISONOUS
BITE
MARKS
Compare the characteristics of pit vipers and nonpoisonous snakes. Note the elliptical pupil, pit below the eye, large fangs, characteristic bite, and single row of subcaudal plates on the belly of the pit viper.
The dog’s behavior: Coral snake venom is neurotoxic, meaning it affects
the nerves and causes weakness and paralysis. Signs may be delayed for several
hours. They include muscle twitching, pinpoint pupils, weakness, difficulty
swallowing, shock, and collapse. Death is by respiratory paralysis.
TREATING SNAKEBITES
First identify the snake and look at the bite. If the snake is not poisonous, clean
and dress the wound as described in the section on Wounds (on this page). If it
appears the dog has been bitten by a poisonous snake, proceed at once to the veterinary hospital. (If the snake has been killed, take it with you for identification.
If not, try to describe it as completely as you can.) Some specific precautions:
• Keep the dog quiet. Venom spreads rapidly. Excitement, exercise, and
struggling increase the rate of absorption. If possible, carry the dog.
• Do not wash the wound, as this increases venom absorption.
• Do not apply ice, as this does not slow absorption and can damage tissue.
• Do not make cuts over the wound and/or attempt to suck out the
venom. This is never successful and you could absorb venom.
• Be aware that the snake’s fangs may be venomous for up to two hours
after it dies, even if you have cut off the head.
Veterinary treatment involves respiratory and circulatory support, antihistamines, intravenous fluids, and species-specific antivenin. The earlier the
antivenin is given, the better the results. Because signs of envenomation are
often delayed, all dogs who have been bitten by a poisonous snake—even
those who don’t show signs—should be hospitalized and observed for 24 hours.
If you live in an area where your dog is likely to come in contact with poisonous snakes, you may choose to take him through sensitization training. A skilled
professional will use an electric collar to train your dog to fear and avoid snakes.
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