Most if not all of you have seen what we call a “daddy long legs.” You may have even heard the rumor that they ‘have the most powerful venom of any spider, but their fangs are too small to penetrate human skin.’ Well, I hate to break it to you, but daddy long legs cannot have the most potent venom of any spider because half of them aren’t even spiders. 

The term does not refer to a singular species but rather any spider-looking creature with a small body and really long, really skinny legs. So, you may be wondering, what are these creatures then? And how can you tell the difference?

The ones you will typically find outside are arachnids known as harvestmen, while the ones you will typically find inside are known as cellar spiders. Harvestmen have fangs but no venom glands to go with them, so they are not venomous in the slightest. They also lack spinnerets of any kind and therefore cannot make silk, let alone spin webs. 

Harvestmen also have only two eyes instead of eight. Their most noticeable trait though, is what is known as a “fused body,” or one part that contains everything. All spiders have two main body parts, the cephalothorax, which is where the eyes, fangs and legs are located, and the abdomen, which is where the spinnerets and various internal organs are located. To the naked eye, harvestmen look like orbs with legs, while cellar spiders look like dots with legs and a peanut-shaped butt.

Both types of arachnids pose no threat to humans. In fact, having cellar spiders in your home is a good thing. They are quite proficient at ridding your abode of actual pests that will do actual damage to your house. 

For example, silverfish, one of the many insects they prey on, will eat books, clothes and your food. Grain weevils raid your pantry and eat all of your pasta, so unless you like mac and weevils, you won’t want them there. Ants might not only raid your kitchen, but they may also eat your house. Mosquitos will eat you. Flies throw up on every object they land on, which includes the sandwich you were eating.

That being said, those with arachnophobia would probably find the long, wiry legs and long skinny abdomens of cellar spiders to be the stuff of nightmares. If it helps, cellar spiders are some of the least aggressive arachnids I’ve ever encountered. I have held a few with my bare hands and never had one bite me or even give any indication that it wanted to do anything other than run. 

Upon encountering a cellar spider, it will probably respond in three ways. They may decide to take those long legs and nope right out of your vicinity. They may stay as still as possible, hoping that we won’t see them if they don’t move (are these guys watching too much “Jurassic Park?” Is that why they think that would work on us?). Lastly, they may begin bouncing on their web to get it to vibrate — a hilarious attempt at intimidation. Note that none of these responses include biting. You have to be harassing it for a long period of time to get it to bite you as a last resort. They’re saving that venom for their food, which is required for eating since they don’t have any teeth.

In short, the term “daddy long legs” does not refer to one species of spider but rather many types of arachnids. The myth that daddy long legs have the most potent venom of any spider but fangs too small to pierce the skin is completely false. While both harvestmen and cellar spiders can puncture the skin with their fangs, they wouldn’t want to and couldn’t hurt you even if they did. 

Knowing the difference between the two could prove helpful to both you and the local arachnid population. Cellar spiders are found indoors and should stay put so they can pay their rent by keeping your house pest-free. Harvestmen, on the other hand, don’t want to be indoors. They’re much happier outside where they can run around to their tiny heart’s content. They usually only end up indoors by accident, so if you see one in your house, take it outdoors. They’ll appreciate the lift.