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Rattlesnake Bites the Dog
The dos, the don’ts, and the mumbo jumbo myths

We all love to bask in the California sun and rattlesnakes are no exception. Snakebite envenomation is something that is frequently seen in the ER, in fact, we treated three pets for this just this past weekend alone! Sadie, an 11-week old Cocker Spaniel, was one of those patients. She was gardening with her Mom when a rattlesnake bit her.

Poisonous snakes of the United States belong to two groups: pit vipers and elapids. Pit vipers are the largest group and include at least 26 subspecies of rattlesnakes (Crotalus spp.), with the Western Rattlesnake being the most common in our region. Click this link for an excellent resource guide that includes pictures of the many species of California rattlesnakes.

How does the venom work?
An understanding of the function of venom is helpful in appreciating how envenomation works. The snake uses its venom to immobilize the victim and predigest body tissues. There are over 50 types of enzymes in pit viper venom, with a minimum of 10 in any individual snakes venom.  Additionally, there are many other non-enzymes present in the venom, called killing fractions, which are 50 times more toxic than the “crude” venom. When the venom destroys the body tissues, it is possible for up to 1/3 of a pet’s body fluid to be lost into the tissue spaces within several hours, which can result in life-threatening drops in blood pressure resulting in shock.

What makes a bad bite worse?
Several factors influence the severity of snakebites. The most important factors are the volume of venom injected and the toxicity of the venom itself. Other factors include:

  • The amount of regenerated venom since the last bite: there is more venom and it is more concentrate if the snake hasn’t bitten in a while.
  • The age of the snake: younger snakes have more “potent” venom.
  • Aggressiveness of the snake: the more threatened they feel, the more concentrated the venom.
  • Motivation of the snake: offensive strikes are more severe.
  • The size of the pet being bitten: smaller dogs and cats are more severely affected than large dogs due to their small body size to venom ratio (less body to “absorb” the amount of venom).
  • The size of the bite.
  • The location of the bite: the “best” place to be bitten is in the legs or face as the regional swelling and changes in the local blood supply can actually slow the uptake of the venom; envenomation to the body is more concerning as the broader area allows for the venom to be absorbed more rapidly; bites to the tongue are the worst and result in rapid and devastating clinical signs.
  • The time elapsed from bite until seeking medical treatment.
  • The amount of physical activity since the time of the bite.

What are the general signs of a snakebite wound?
Snakebites are not always easy to diagnose, especially if it was an unobserved bite and if a pet has a heavy hair coat that may hide puncture wounds. With pit viper bites, you can usually see bleeding puncture wounds and single or multiple puncture sites may be observed. The initial signs are marked swelling, which is due to the tissue destruction and body fluid “leaking” into the damaged area (see the picture of the little Chihuahua, showing a what a typical bite to the face looks like). Clinical signs may develop immediately or be delayed for several hours. Bruising and skin discoloration often occurs within hours of the bite because the venom causes the blood to not clot. There is usually intense and immediate pain at the site of the bite, which helps differentiate snakebites from other causes of swelling, and swelling is generally progressive for up to 36 hours. You can also see collapse, vomiting, muscle tremors, and depression in breathing.

What to do if a snake bites your pet:

  • If your pet is bitten by a snake, it is best to assume it is a venomous bite.
  • Seek veterinary attention as soon as possible!
  • If the swelling is not in the face, muzzle your pet (if you can do it safely) to avoid being bitten: snake bites are very painful and your pet may unintentionally snap at you; if the swelling is in the face, avoid touching this area all together.
  • Immobilize the part of your pet that has been bitten by the snake, if this can be done safely; try to keep the area at or below the level of the heart.
  • Keep your pet calm and immobile, carry if necessary.

What NOT to do (and the mumbo jumbo myths)

  • Do not try to suck out the venom! (This technique only works for John Wayne in old Western movies).
  • Do not attempt to “make an X” and cut open the area around the bite (you will only cause a wound).
  • Do not bother to use a Snake Bite Kit or Extractor Pump (they will actually do more harm to your pet- and your wallet!).
  • Do not apply ice to the area: this constricts the blood vessels locally and actually concentrates the venom causing severe muscle damage to the area.
  • Do not rub any substances into the bite: the venom has entered the blood stream, and any substance applied topically is ineffectual.
  • Do not apply a tourniquet: you will only succeed in causing further tissue damage and possibly create a need for limb amputation.
  • Do not allow your pet to move about freely.
  • Do not attempt to capture the snake for later identification (you’d be surprised…)

Tips for prevention:

  • Stay on open paths while hiking with your pet.
  • Keep your pets on leash away from high grass and rocky outcrops where snakes like to rest.
  • Don’t let your pet explore holes or dig under rocks.
  • Keep an open ear for that telltale rattling noise and keep your pet at your side until you determine where the sound is coming from, and then move slowly away.
  • If you see a snake that sees you, remember that a snake can strike only a distance of half its body length; give the snake time to “just go away” as they are not looking to interact with you or your pet.
  • Don’t let your pet examine a dead snake as they still can envenomate.
  • For around your home: cut off the snakes food supply and shelter by mowing close to the house, storing firewood away from the house, plugging up holes in the ground, and limiting birdseed waste which can attract rodents to your home.

What is the treatment?

Since the onset of clinical signs can be delayed for several hours, all pets that have been bitten by a snake should be hospitalized for at least 12 hours and ideally 24 hours. Although most pets generally need to be supported and monitored, the vast majority (95%) do survive with early and proper treatment.

Antivenom is the only proven treatment against pit viper envenomation, and the earlier it is administered, the more effective its action.  The biggest downside to antivenom is cost, and it can range anywhere from $450-$700 per vial.  Usually a single vial will control the envenomation but several vials may be necessary, especially in small dogs or cats.  Many animals may do “fine” without it, but it does decrease the severity of clinical signs, as well as speed overall recovery with a reduction in complications. Blood work is also recommended to monitor your pet’s platelet count as well as clotting times of the blood. IV fluid support, intensive pain management, antibiotics and wound monitoring are required for best clinical outcomes. Blood and plasma transfusions are sometimes needed in severe envenomation.

What about the vaccine?
There is a “snake-bite vaccine” that may be useful, but there have been no controlled studies for its effectiveness. The main benefit of the vaccine is that it may create protective antibodies to neutralize some of the injected venom, and in turn may lessen the severity of the clinical signs. One of the biggest myths is that if your pet has had the vaccine, then they don’t need to be treated if they are bitten; this is not true, and they still require the same treatment despite being given a vaccine or not!

Thankfully, most snakes will try to avoid you and your pets and typically only bite as a last resort. But if your pet does happen to get bitten by a snake that you think might be venomous, it is best to err on the side of caution and get medical attention immediately. As always, feel free to ask questions or leave comments!

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Veterinarian Shea Cox has enjoyed an indirect path through her professional life, initially obtaining degrees in fine arts and nursing. She later obtained her veterinary medical degree from Michigan State University in 2001 and has been practicing emergency and critical care medicine solely since that time. In 2006, she joined the ER staff at PETS Referral Center in Berkeley and cannot imagine a more rewarding and fulfilling place to spend her working hours. In her spare time, she loves to paint, wield her green thumb, cook up a storm and sail. Her days are shared with the three loves of her life: her husband Scott and their two Doberman children that curiously occupy opposite ends of the personality spectrum.

CommentsPost a Comment
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Submitted by Anonymous | July 13 2012 |

Is that poor baby okay now? Ow, her poor little snout!

Submitted by Jennie | July 13 2012 |

OMG is she ok?!

Submitted by Shea Cox DVM | July 14 2012 |

She did great and went home in 24 hours! :) Better yet, no complications followed.

Submitted by Anonymous | July 13 2012 |

The article was informative and well written, but I have to ask why are you listing the pic as a Cocker Spaniel? I am sure it was just a mistake but the dog in the pic with this article is not a Cocker Spaniel.

Submitted by Shea Cox DVM | July 14 2012 |

Anonymous~ great catch! Just so you know, there were supposed to be two pictures posted within the blog (which I don't post, I just write :).
The young Cocker was supposed to be the cover picture at the top, and in its place was the Chihuahua. If you keep reading the article, you will see the sentence, "The initial signs are marked swelling, which is due to the tissue destruction and body fluid “leaking” into the damaged area (see the picture of the little Chihuahua, showing a what a typical bite to the face looks like)" and that photo was supposed to be inserted in this area. Hope that clears the confusion!

Submitted by Teresa | July 13 2012 |

Argh....as a zoo employee & educator one of my pet peeves is the incorrect use of poisonous (used at beginning of 2nd paragaph) instead of venomous.

Submitted by Shea Cox DVM | July 14 2012 |

Teresa~ duly noted! And yes, you are correct. To clarify in a nutshell to the general public, all venoms are a poison, however not all poisons are venoms. I try not to split hairs when attempting to get a general point across to the majority of people; otherwise the blog would be written in technical speak that only a medically trained person would understand. So, please forgive my interchangeable phrasing used :).

Submitted by Todd | December 29 2013 |

Better yet you need a hobby the article may not have been written by someone as "special" as you so how bout you relax and not worry about a persons grammar

Submitted by Monika | July 13 2012 |

I think dog owners need to be aware as well that most vet clinics do not carry the anti-venom and here in Las Vegas there is a 2 hour wait for the anti-venom, which means little dogs may stand little chance of survival. I do not expect all vet clinics to carry this life saving medicine, but if we had a few that happen to be nearest popular hiking places our furry friends would get better and faster care. When dogs do not get the venom, they can end up staying for a month in the hospital with a very expensive bill. This makes no sense to me.

Submitted by Shea Cox DVM | July 14 2012 |

Hi Monika~ thank you for taking the time to comment. Just to clarify, antivenom is not needed or mandatory to save the life of a dog. For instance, I am not able to give antivemon to many dogs because of understandable financial reasons of the pet parent. However, it does help them get better quicker, reduces complications, and helps prevent the clotting disorder that can happen in the body. The ideal time frame to give the antivenom is within the first 4-8 hours of envenomation (a 2 hour wait time to get the drug would be fine), and I have still seen it given up to 12 hours later or longer. I have never heard of a dog having to be fully hospitalized for a month following a bite unless some unusual complications happen such as loosing an extensive amount of skin and having a secondary infection on top of that. Thankfully, the vast majority of dogs do excellent and get to go back home :).

Submitted by Kris | July 13 2012 |

One of the best things I ever did for my dogs was put them through rattlesnake aversion class. I know many people have strong feelings about using shock collars, but used properly they can be effective training tools. After the class my dogs avoided all snakes; even my pet boa constrictor, which they had always been curious about. The class teaches the dogs to recognize the snake by sight, smell, and sound. By the end of their training session, which is about 20 minutes (if that)the dogs have learned to give reptiles a wide berth. Well worth the cost. BTW they also train horses and llamas to avoid rattlers.

Submitted by Sue | April 3 2014 |

My dogs and Llama participated in a Rattlesnake aversion training after one of my dogs was bitten. I found it to be highly effective, since the training, we have encountered several Rattlers out on the trails and my animals jumped out of the way!

Submitted by Anonymous | July 13 2012 |

Do you reccomend snake snake training?

Submitted by Shea Cox DVM | July 17 2012 |

Hi Anonymous~ I've heard good, neutral and bad results with aversion training but I don't have any personal experience with it to be able to make a knowledgeable comment. Unfortunately, there is such a spectrum of results reported, that without direct experience on my part, it is difficult for me to recommend it one way or the other.

Submitted by Dave Trowbridge | July 13 2012 |

Not only does sucking on the wound do no good, it will destroy your sense of taste for several days. I can tell you from experience that the sensation and effect is almost exactly the same as battery acid.

Submitted by Roy Hauer | June 21 2013 |

We have mini Doxies, and our little male was bitten 2x and his daughter was bitten 2x on the muzzle the same day, (most likely by a timber rattler) Both recovered with appropriate Vet treatment. 2 weeks later the little male again got bit twice on the face, and again with quick response and treatment recovered just fine. About 2 months later same little male was bitten again, this time unbeknown to us for a couple of hours, and was found dead.

Submitted by heather | June 25 2013 |

My 8 year old lab/shorthair dog was bitten on her nose and leg last Monday by a very angry baby diamondback rattlesnake. The dog was treated immediately at a Pet hospital then sent home only to worsen several hours later. She was then treated two more days on IV's and is now home. She is on an antibiotic, benedryl, diuretic, and a steroid 2-3 times per day of each. She still worries me--weight loss, shaking, panting, (she isn't typically a panting dog), lethargic, and just not her hyper, active, jumping, barking self. She has always licked everyone she meets and doesn't even do that. If we let her outside she goes straight to her kennel instead of running and barking up and down our fence like she always has. Is this normal behavior after a bite wound of this nature? It this the drugs? Are the drugs causing or is she having reactions to the venom as to why she pants and shakes a great deal. I am still so worried about her. Any suggestions would be appreciated. Thanks

Submitted by Rebecca | August 30 2013 |

Has your sweet dog recovered? I hope so!

Submitted by Elizabeth | July 23 2014 |

If it were me, I would definitely take her to another vet to get a second opinion

Submitted by Paula | September 15 2013 |

My dog was bitten today, received anti venom and sent home with us later to get IV's and antibiotics(I used to be a nurse) I'V infiltrated but we are going back to vet tomorrow. He responded well to anti venom hope he pulls through still very lethargic but has had Benadryl and has a pain patch on so hopefully sleepy from that. Is it true that if he is bitten again he has a greater chance of dying? He is an American Bulldog and all but impossible to keep out of the woods. Jumps our fence no problem.

Submitted by allaboard | September 29 2013 |

I felt I should relate my experience with a rattlesnake biting my dog, if for nothing else than to raise your optimism. 66 hours ago my Belgian Tervuren (shepard) was bitten on the underside of her neck by a rattlesnake. She had startled the snake and the snake made a quick strike and returned to the coiled position hissing and rattling. She seemed more spooked than anything else at first...she moved very slowly and repeatedly try to find somewhere comfortable to lay down. I tended to removing the snake. I remained optimistic and began to learn all I could very quickly about dogs reaction to viper bites....most information was severe and treatment costly....however I also learned of the variables in the types of bites...dry bites, glancing bites and the dogs weight , type of coat, age ,etc that would all factor in to the severity. I remained optimistic. I did not seek veterinary help. I observed my dog for symptoms.... for the first 12 hours the only symptom was drooling....no swelling, no whining...no vomit...no blood...no crying. She did continue to amble and try to be comfortable. The next morning she was more mobile, eating and drinking....but still a little lathargic..."spooked". I felt relieved...the bite must have been a glancing strike or dry bite...maybe a single fang, etc...regardless it did not appear to be severe. However, within the next 12 hours her face and neck had swollen significantly....her jowels were extremely bloated. It took 24 hours for the swelling to begin...regardless of the swelling,.her temperment was much improved...energy level was back....she seemed very much her self. I remained optimistic and still did not seek medical assistance. The following morning the swelling was all but gone...it has been less than 72 hours and she seems to have survived. It was a difficult experience for both of us. I remained optimistic throughout...due to the lack of severe symptoms or discomfort, I risked my dogs life...I gambled. I was fortunate...no she was fortunate.

Submitted by Laura | April 22 2014 |

This article was informative. Saturday, April 19, our 7yr old border collie was bit on the lip after chasing something into a hole, and putting her nose down the hole to scare it out. We thought it was a ground squirrel or scorpion. There was so much blood and she was quivering. Her tongue started to get a blue colored spot in the area of the lip bite, and the internet said that meant "lack of oxygen" so I panicked! We immediately took her to an emergency vet hospital.
The vet said it was a rattle snake bite, but didn't know if it was Diamondback or Mohave green, which was even more deadly.
Vet immediately started a sub-q flush of fluids, and we authorized immediate treatment. She was then hooked up to an IV with antibiotics, anti-histamine, pain meds and anti-inflammatory meds. They recommended keeping her for observation as her face was swelling, and her lip was very fat.
As the days progressed, her face swelled even more. The swelling did not stop expanding until late Sunday, 4-20-14, and we were told she was in stable condition and the blood smear showed there was venom in the blood, but had not damaged any organs and there was no neurological damage. We could come pick her up before closing.
The conditions were that we keep here on the same meds she was getting through the IV for another 10 days and bring her back for a follow up 5-1-14. We were so relieved to know she had survived, and would probably be ok. Her throat was the size of a filled water balloon, or one of those bull frogs necks that blow up when they croak. The poor thing had to be in extreme pain, but was so glad to see us and go home.
We were happy to have here home.

Submitted by Jay Beard | May 14 2014 |

Our little Emily was just bitten by what was likely an adolescent timber rattler, as the fang seperation was about 1/2" to 5/8" separation. She is now in the care of our local animal hospital, and has just had a second dose of anti-venom administered. we are hoping she makes it, Emily is only 8 months old and about 9.5 lbs. We are hoping that there is no organ damage, but only time will tell. I Hope we are as fortunate as some of the other bloggers here. God bless and thank you all for the well wishes for emily

Submitted by donna | April 30 2014 |

How long does the swelling last in the dog? Mine was bitten yesterday had the anti venom treatment and is still swollen 30 hours later... He is fine though and blood tests are all good... just wondering if the swelling takes several days to go down?

Submitted by Robbie | July 28 2014 |

Last week we took our Briad to a small fisherman's port in north Mallorca, Spain, he showed fear at one point when I went to touch his face and I saw hehad 3 puncture wounds on his nostril. I thought it might have been from wasps but there were no barbs in them. It was curious because the black skin around the wound had turned white. There was also a fine red circle around each hole. Does that sound familiar to anyone?

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