Rattlesnake bites on dogs
Rattlesnakes are a group of venomous snakes. The 36 known species of rattlesnakes have between 65 and 70 subspecies. Rattlesnakes are predators that live in a wide array of habitats, hunting small animals such as birds and rodents. The threat of envenomation, advertised by the loud shaking of the titular noisemaker (“rattle”) at the end of their tails, deters many predators. Rattlesnake bites are the leading cause of snakebite injuries in North America. However, rattlesnakes rarely bite unless provoked or threatened; if treated promptly, the bites are rarely fatal. Most species live near open, rocky area, but they can live in a variety of habitats, ranging from wetlands, deserts, and forests, and from sea level to mountain elevations. Rattlesnakes prefer a temperature range between 80 and 90 °F (26 and 32 °C).
Dogs are at risk for rattlesnake bites; in fact, dogs are about 20 times more likely to be bitten by venomous snakes than people and are about 25 times more likely to die if bitten. Snake bites are life threatening, extremely painful, expensive to treat, and can cause permanent damage even when the dogs survive.
The initial signs are marked swelling, which is due to the tissue destruction and body fluid “leaking” into the damaged area. 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 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 altogether. 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.
There is a “snake-bite vaccine” that may be useful, but there have been no controlled studies of its effectiveness. The main benefit of the vaccine is that it may create protective antibodies to neutralize some of the injected venoms, and in turn, may lessen the severity of the clinical signs.
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, and the earlier it is given to a dog, the more effective its action.