Black Widows and Dogs

October 3, 2022

We often associate our fur-legged friends being bit by ticks and fleas. These pesky creatures are known for their persistency and potential health risks. Ticks and fleas are parasitic insects that require hosts to complete their life cycle. In contrast, spiders, such as the Black Widow, are not parasitic, meaning that they do not require a dog or cat to live off of. Although many spiders would prefer to hide from other animals, there may be situations when this does not happen and a spider bite occurs. Generally, almost all spiders inject venom into their bites. For the majority of spiders, the amount of venom that is injected is very small and not lethal to your dog. For Black Widow spiders, however, even the tiniest amount of their venom can cause life threatening health problems.

What happens when a dog gets bitten by a black widow spider and what are the common symptoms?

Black Widow spider venom contains a neurotoxin that can cause clinical signs related to the nervous system. It excites the dog’s neurons and can lead to tremors and or painful muscle twitching. Their bites can also cause severe muscle cramping and very stiff abdominal muscles. Excitation of the nervous system can lead to an elevated respiratory rate as well as an elevated heart rate. In severe cases, seizures, paralysis, and respiratory arrest can occur. Vomiting and diarrhea are among the most common initial symptoms. Excessive drooling and nausea are also common. Pain and swelling around the bite area is also a routine symptom. This can be very painful for your dog and needs to be treated right away.

Areas to avoid

Black Widows tend to hide in dark and secluded areas. A woodpile, under an old piece of furniture in the garage, and cluttered areas where they have a sense of protection are some of the most common places. Although these spiders are not generally aggressive, they certainly are dangerous. They tend to go on the attack when they feel that they are at risk. By keeping your dog away from areas such as this will limit his chances of being bit by a Black Widow spider.

What time of year are Black Widow spiders most active and what states are they found in?

Black Widow spiders emerge in early spring when mating occurs through early summer. Young spiderlings continue to grow into adults during the spring and summer and mature by late summer. Adult widows are most prevalent during late summer and fall. In the US, they are found in all the four southwestern deserts (Great Basin, Sonoran, Chihuahuan, and Mojave). They can also be found in Florida and Texas.

What to do if your dog has been bitten by a black widow spider?

Although many spider bites are not witnessed, watching for spider bite symptoms will help protect your dog from possible serious health issues. If your dog has acute swelling noted in a particular part of his body, a fever, and is lethargic, there is a good possibility he was bitten. Contacting your veterinarian immediately to report this is very important as time is a factor. An antivenin is available for Black Widow spider bites which can help to reverse the effects of the bite. Intravenous fluids may also be provided for extra support, and muscle relaxer medications can be administered to help with your dog’s muscle twitching and tension. They key is to identify the symptoms and notify your veterinarian as soon as possible.