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How to Tell If Your Dog Has Been Bitten by a Spider

Nicole Cosgrove Profile Picture

By Nicole Cosgrove

spider on web

It’s hard to imagine two animals more different than dogs and spiders. One is cute, cuddly, and furry, and the other is literally made of nightmares. Okay, that’s not completely true. Spiders are cute in their own way, and they’re incredibly beneficial to the world’s ecosystem.

Of course, none of that matters if one of those spiders bites our beloved pooches. Certain spiders can actually be quite dangerous for dogs, so it’s important to know whether your dog has been bitten or not.

However, most dogs are unable to inform their owners that they’ve been bitten (with the exception of Droopy and Scooby-Doo). That’s why it’s so important that you can recognize the signs of a spider bite.

To help you in that regard, we’ve put together a quick guide to determining if your dog has been bitten by a spider.Divider 8

How to Tell If Your Dog’s Been Bitten by a Spider

It can be difficult to tell if your dog’s been bitten by a spider after it happens unless you witnessed it happen or found the spider in your dog’s fur. What does a spider bite look like on a dog?

spider on web
spider biteImage Credit: nuzree, Pixabay
As a result, you’ll likely need to look for certain behaviors after the fact, like:
  • Behavioral changes
  • Loss of appetite
  • Lethargy
  • Pain or swelling (especially at suspected bite site)
  • Seizures
  • Weak pulse or increased heart rate

All of these symptoms are signs of a venomous spider bite. If your dog is showing any of these, you should examine their skin underneath their fur to see if you can find a bite location.

Your dog may help you by licking at the bite site or whining if you touch it. However, not all bites are painful, at least not at first, so this isn’t always a reliable indicator.

When examining your dog’s skin, look for a red or irritated area. A raised bump may be present, and the site may or may not be filled with pus or blood.Divider 4

What to Do If Your Dog’s Been Bitten

If you’ve discovered that your dog’s been bitten by a spider, it’s important to act quickly. Many dogs won’t require medical intervention due to spider bite, but if yours does need medical help, then the longer you wait, the more damage that the venom can do. You want to get it neutralized as soon as possible.

If you can, capture the spider that bit your dog (but don’t put yourself in any danger to do so). If that’s not possible, try to take a picture or two so your vet can have an idea of what kind of venom they’re working with.

Then, call your vet and describe the bite and the spider responsible. Your vet will probably want to know what kind of symptoms that your dog is exhibiting, so be as thorough and descriptive as possible.

There’s a good chance your dog will be fine even without visiting the vet. However, if your pup has shown any of the symptoms listed above, especially the more serious ones, then you may need to take them in so the vet can administer antivenin and antihistamines.

If your dog is especially sensitive to spider venom, then full recovery can take weeks. However, most dogs are good as new within a few days.

Dog looking at a spider
Image Credit: Rimma Bondarenko, Shutterstock

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Which Spiders Are Dangerous to Dogs?

Most spiders are completely harmless and are in fact quite beneficial. However, there are a few species in America that pack especially potent venom, so you should take bites from these spiders especially seriously.

  • Black widows: Black widows have extremely potent venom, and in fact, their bites can be fatal in humans. For whatever reason, though, dogs seem to tolerate it well (at least compared to cats and horses, who can often die as a result of a bite). The black widow is known for its black, shiny body with the telltale red hourglass marking on its abdomen and can often be found in woodpiles and similar structures.
  • Brown widows: A close cousin of the black widow, the brown widow is brown, and the hourglass marking on their abdomen is yellow or orange instead of red. According to some estimates, brown widow venom is just as toxic as black widow venom, but they’re far less aggressive, so brown widow bites are less common as a result.
  • Brown recluses: This common species is quite timid, so most bites occur because the dog accidentally stepped or laid on the spider. The brown recluse’s bite generally isn’t painful, so you may not realize that your dog has been bitten until well after symptoms start showing, at which point, necrosis may have already set in. Brown recluses are small and brown, with a violin-shaped mark on their backs, and they build webs in and around wood or cardboard.
  • Tarantulas: The good thing about tarantulas is that they’re easy to find and identify. These massive spiders aren’t as venomous as you might expect, given their size, but their bites are extremely painful. Your dog likely won’t be in mortal danger or suffer any lasting damage, but the affected area will likely be tender for several days. Also, if your pup ingests the tarantula’s hair, expect them to vomit or drool excessively.

Even though most of these spiders carry highly toxic venom, your dog’s prognosis is good, especially with medical intervention. However, the smaller the dog, the worse their odds, so be cautious when dealing with a bite on a toy breed.

Also, not every spider bite injects venom. Venom is highly precious to spiders, so some will inflict a “dry bite,” in which no venom is injected, to warn away non-prey animals. Still, you should take every bite seriously until you have reason not to.Divider 3

How to Minimize the Risk of Spider Bites

Spiders are everywhere, so you’ll never fully eliminate them from your home or property. However, there are some things you can do to reduce the risk that your dog will be bitten by a venomous species.

The most important thing is to make your home inhospitable to the eight-legged critters. Both types of widow and brown recluses are attracted to areas like woodpiles and heaps of cardboard, so keeping your surroundings clean will discourage them from moving in.

While tarantulas are common in the American southwest, dogs are most likely to encounter them when they’re kept as pets. You may want to avoid bringing a pet spider home if you have a curious dog, but if you insist on sharing your room with a giant spider, make sure it never gets out or interacts with your dog in any way.

Keep in mind that spiders are attracted to any area where prey is prevalent, so try to keep the insect population around your house under control as much as possible. That means not leaving standing water, emptying garbage regularly, and even spraying your premises with pesticides.

Given how beneficial spiders are, we generally recommend leaving them alone if you see them building webs. That’s not the case with the spiders on the previous list, though. You should take prompt action to kill them if you spot them and remove their webs so others don’t move in.

Divider 2Spiders Are Friends, Not Foes

Spiders may be creepy, but the benefit that they provide vastly outweighs their occasional danger. You might have trouble convincing your dog of that, though, so it’s best to avoid putting your pup in situations where a bite may occur. Luckily, most spiders prefer to be left alone, and they definitely don’t want to waste their venom on an animal that they can’t eat.

Featured image credit: fleglsebastian7, Pixabay

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