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Black Widow Spider Bites in Dogs

Black widow bites can kill dogs.

Spine-tingling dread often occurs in humans when these arachnids are mentioned: black widow spiders. With the red, hourglass-shaped mark on their abdomens, these spiders are venomous, and they cause humans to shudder even more than many other spiders do.

Black Widow Facts

Black widow spiders (Latrodectus spp.) are found all over the world in areas with temperate weather. In the United States, the black widow lives mostly in the south and west, but they have been found in all states except Alaska.

The bite of a black widow spider is venomous, and that venom is about 15 times more potent than that of a rattlesnake (National Geographic: Black Widow Spider). In fact, scientists say that their venom is getting stronger over time.

Only the female black widow can envenomate a victim.

Black Widow Spider Bites

Luckily, black widow spiders aren't particularly prone to biting people. They're shy, stay away from humans, and are wise with their use of venom because they have to replenish it once they use it, which costs them precious calories and energy.

When a black widow spider does bite a person, it can cause muscle pain, nausea, and difficulty breathing, but it is seldom fatal to a healthy adult. Small children, elderly people, and those with other illnesses may become sicker and be at higher risk of death from a black widow's bite.

However, dogs are more likely to be bitten by a black widow than humans are, and the bite can be more serious for them than for most people.

Dogs and Black Widows

Dogs are probably more prone to being bitten by a black widow spider than humans because they are often quite curious and are known for sticking their noses and paws into spots that make for good black widow homes. These types of areas include:

  • Hollow stumps
  • Rodent holes
  • Brush piles
  • Dense vegetation
  • Barns
  • Garages
  • Basements

Dogs may also be more likely to be bitten by a black widow if they encounter one because they don't have innate fear or disdain of spiders and may keep poking at it, trying to play with it.

Dogs are much more likely than humans to develop severe reactions to black widow spider bites, though it is still puppies, older dogs, and sick dogs who will probably fare the worst.

Signs That a Dog Has a Black Widow Spider Bite

Dogs that have been bitten by a black widow spider and had venom injected into them may display the following signs:

  • Rigid abdominal muscles
  • Difficulty breathing
  • Muscle twitches
  • Restlessness
  • High blood pressure
  • High heart rate
  • Drooling
  • Seizures
  • Paralysis
  • Respiratory arrest

Treatment of Black Widow Bites in Dogs

It can be difficult to diagnose black widow bites in dogs because the signs could be the result of many other illnesses, and owners often do not see the bite occur. If the veterinarian suspects a black widow bite, treatment can include:

  • IV treatment with antivenin
  • Monitoring and treating for seizures
  • Watching for and treating high blood pressure
  • Muscle relaxers and pain medications if needed
  • Treating low blood sugar if it occurs secondary to the muscle twitches
  • Oxygen therapy if needed for respiratory difficulty

Dogs may recover with aggressive treatment for black widow spider bites.


Works Cited


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