You see them around so often around your home, scurrying to and fro, that you can’t help but wonder,
“Are daddy long legs poisonous to dogs?”
After all, your canine companion has shown great curiosity towards the little insects, and the last thing you want is for their life to be endangered! Hasn’t it been said that daddy longlegs are actually the most venomous creature in the world…?
Thankfully, this just isn’t true. Firstly, ‘daddy longlegs’ isn’t the name of just one creature, but instead of three different animals that all share the same trait: long, skinny limbs.
What they all also share beyond the name however is a complete harmlessness in different ways. One doesn’t have venom glands (and therefore by logic can’t be poisonous), another’s mouth is too small to bite- and the last doesn’t even have a jaw to bite with at all!
Two spider species that you do need to watch out for are the widows and recluses. Both have highly potent venoms that can cause symptoms such as muscle pain, tremors, incoordination, and paralysis. Vet treatment is necessary in this case for a dog to recover successfully.
Despite the persistent and popular urban legend that no doubt inspired you to ask this question in the first place, daddy long legs “spiders” are not poisonous at all- to humans or to canines.
I’ve put speech marks around “spiders” because there are at least 3 different creatures that have earned the name of ‘daddy longlegs’ around the world- one of which isn’t even an arachnid at all!
The three animals that are commonly called daddy longlegs are the cellar spider (Pholcus phalangioides), harvestman arachnid (Opiliones) and the crane fly (not-a-spider).
Despite the common and oft-repeated misconception, none of the three are among the most venomous animals in the world (or even really venomous at all, for that matter).
The cellar spider, which is also known as the skull spider, is luckily nowhere near as deadly as its name makes it sound.
Cellar spiders are usually small, gray and very delicate, with long thread-like legs from which they get their nickname. They like to live in dark and undisturbed areas, which explains why they are most commonly found in the corners of your home.
Don’t be fooled by their lanky, wobbly appearance however; despite posing no threat to humans, they are fierce hunters of insects and indeed, even of other spiders.
Cellar spiders use their web not as an adhesive like so many other spiders do, but instead as a kind of net that they can throw onto their prey from a safe distance to trap and bind them.
Pholcidae have been known to hunt such formidable adversaries as huntsman, funnel weaver, black widow, and even the notoriously deadly redback spiders- an arachnid that produces a venom strong enough to kill humans.
It is probably this impressive predatory ability that has created the false reputation of the cellar spider being the most venomous in the world. After all, a spider that hunts and eats other spiders capable of killing humans must be even more poisonous, right?
Wrong. In fact, there has been no evidence to show that cellar spiders are deadly venomous. To the contrary, they have been shown to be not all that venomous at all. It has been shown in recent studies that pholcid venom is not very potent even against insects.
Moreover, an experiment carried out by the famous Mythbusters duo showed cellar spider venom to be much less potent than that of a black widow’s.
When one host’s hand was inevitably offered to be bitten, the bite did manage to pierce skin but resulted in nothing worse than a temporary, mild, burning sensation.
It is true though that cellar spiders have a short fang structure that would have a hard time piercing human (or canine) skin. So, at least the part of the urban legend that says “the Daddy Long Leg’s mouth is too small to bite” has some ground.
Final Cellar Spider Venomous Verdict: Not Poisonous.
The harvestman or harvester is another animal that is commonly called “daddy longlegs”, again no doubt due to the very long limbs that it possesses.
To add further to all the confusion: Though the harvestman is an arachnid, it is not a spider, and may instead be more closely related to mites. Unlike true spiders, its body appears to only have a single, oval structure. It also has only a single pair of eyes, and no silk or venom glands.
However, just like the cellar spiders above, harvestmen have very small grasping claws as their mouthparts and are not able to bite humans or dogs effectively. Even if they do manage to have a nip, their lack of venom glands make them relatively harmless.
Case closed. Final Harvestman Venomous Verdict: Not Poisonous.
In truth, the crane fly looks more like a giant mosquito than a spider, but it does also possess the uncannily long legs shared by all ‘daddy longlegs’ moniker-carriers.
The crane fly has wings and is able to fly (as suggested by its name)- which would be an absolutely terrifying thing for a spider to be able to do. Thankfully, the most dangerous thing that a crane fly is prone to do is to fly unwittingly into windows and lights.
Crane flies do not bite or sting, and due to a lack of mouthparts cannot hunt or hurt other insects- let alone humans or canines. Unless your dog secretes nectar in a biological miracle, it is completely safe from craneflies.
Crane flies also do not have an ounce of venom inside them.
Final Crane Fly Venomous Verdict: So Harmless That It’s The Opposite Of Poisonous!
Of the 30,000+ species of spiders around the world, most are poisonous. That’s not welcome news to anyone’s ears.
What’s lucky for us and for our dogs is that most of these spiders don’t have fangs that are big or strong enough to penetrate the skin. If they’re unable to inject venom into their intended target, that makes them effectively benign.
There are 2 main groups of spiders that are responsible for the majority of poisonous spider bites in the US: the widows and the recluses.
Most people these days know the black widow as a famous Marvel superhero, but her namesake can be just as deadly.
A small black spider with a red hourglass marking, widows carry a venom that contains a neurotoxin that causes cells of the nervous system to become extremely agitated.
A black widow bite is moderately painful at first, and more serious symptoms such as cramping, muscle pain, stomach pain, tremors, diarrhea, vomiting, incoordination, agitation and paralysis can develop in the following hours.
In contrast, brown recluse bites do not hurt at first, but a blister will begin to form within 2 to 8 hours. The blister then develops gradually into a bulls-eye shape, with various shades of color such as white, red and black signally tissue death.
Brown recluse bites mostly cause localized pain, reaction and damage, but can sometimes also result in kidney damage and blood clotting disorders.
If you think that your dog has been bitten by a spider, it’s very important to try to catch the spider and bring it to the vet for identification. It may be that the spider isn’t venomous and all that is needed is a small amount of local wound therapy if the area is inflamed.
To do this, the vet will firstly clean and disinfect the area. Following that, pain medication may be given if it is deemed necessary.
If your dog has been bitten by a venomous spider such as a black widow or brown recluse, there’s nothing suitable that you can do at home and it should instead be taken to the vet as soon as possible.
When a venomous spider bites a dog, the venom is injected into the skin and begins rapidly to make its way into the bloodstream. From there, the venom flows around the body to various organs such as the brain and heart, where it can become lethal.
An anti-venom is available to treat black widow bites and works very quickly. In fact, it can resolve clinical signs in as little as 30 minutes.
However, there currently isn’t any antinvenin available in the US for brown recluse nips. Supportive care such as IV fluids, muscle relaxants, pain medication, and anti-seizure medications are administered instead.
Treated promptly, bites from these venomous spiders take just one to three weeks to heal fully and serious complications or death is very rare.
Oh, how the tables have turned. What happens when the biter becomes the bitee, and your dog munches on a spider?
If it’s a daddy longlegs (whatever the creature), your dog will most likely be no worse for wear- assuming that it doesn’t have any rare allergy to the venom. Look for any strange reactions such as a swollen mouth or throat in the hours following the spider-swallowing incident.
Even if your dog were to eat venomous spiders such as black widows or redbacks, it most probably won’t suffer any adverse effects unless the arachnid manages to bite the dog’s mouth or throat on the way down, or if the dog has an allergic reaction to the potent venom.
Otherwise, the spider is unlikely to be harmful in the digestive system as the venom is designed to be injected by the fangs directly into the skin and bloodstream- not digested in the stomach.
Once the spider is inside the dog’s stomach, the acid will begin to break it- and the venom inside- down. Since spider venom is protein-based, the acidic environment will effectively denature and neutralize it, making it ultimately harmless.
Still, it’s a good idea to monitor your dog over the next few hours and days if it has recently been in close contact with known venomous spiders. If it starts to have an upset stomach, or shows signs of lethargy, dizziness or has difficulty breathing, take it to the vet ASAP.
So, are daddy long legs poisonous to dogs? No.
There are 3 different animals that are commonly called ‘daddy longlegs’. However, it doesn’t matter whether the dog encounters a cellar spider, harvestman arachnid or crane fly- they are all equally harmless.
The cellar spider’s mouthparts are too small and weak to pierce human or canine skin, while the harvestman doesn’t possess any venom at all inside its body. There’s even less to speak of for the crane fly; after all, it isn’t even a spider!
So, no matter whether your dog eats (or more improbably, is bitten by) a daddy longlegs, there’s no need to worry. It’ll be just fine!