Elimination Consideration: Do Spiders Poop?

Written by Kristen Holder
Updated: November 14, 2022
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Spiders are not something that people look forward to seeing in their homes. While some people are so fascinated with spiders that they keep them as pets, most of us are repulsed.

Yet when we see an arachnid in our homes, it sometimes leaves us with an elimination consideration: Do spiders poop?

Do Spiders Poop?

Triangulate Cobweb Spider (Steatoda triangulosa)

Spiders poop because anything that eats must eliminate waste.


Yes, spiders poop. Anything that eats must eliminate waste. Poop is a result of their digestive process just like it is with humans.

Spiders don’t digest insect shells. Instead, they throw them up after they’ve eaten. This means there isn’t anything hard that a spider will need to pass through its body to digest.

Their resultant poo is runny almost like ink.

Do Spiders Pee?

No, spiders do not pee. A spider poop can be seen as a liquid white substance and spiders only have one hole for releasing waste. Both pee and poop are combined for a spider which comes out as one waste product from their anus.

There is nothing like urine production taking place in a spider’s body. There are special digestive organs that pass uric acid as a solid instead of a liquid. Humans pass uric acid when they urinate.

Do Spiders Fart?

Nobody is sure if spiders fart.

©Kala Stuwe/Shutterstock.com

Nobody is sure if spiders can fart and there aren’t any scientific studies that have been done on the subject. Some people think that spiders produce enough gas during the digestive process to pass it like other insects. Others think they don’t fart because of their diet.

Their diet is mostly liquid since their venom breaks down their prey before they consume it. Since their liquid diet doesn’t involve the breakdown of solids, the chances that gas is produced are minimal.

However, there are bacteria in a spider’s digestive tract that help to break down food. These bacteria when studied in other situations almost always emit a byproduct of gas that would have to be expelled.

Spider farts remain a mystery until someone decides to fund research into studying arachnid flatulence.

What Does Spider Poop Look Like?

A spider poop isn’t solid, so it looks like dark stains or drips on walls and surfaces. Each spider species has a dump that looks different, but the untrained eye won’t be able to tell.

Their poop usually gathers in one spot below their web, like on the wall in an unused corner with a cobweb. Any dark or undisturbed place can make a good spider refuge, so their poop can show up in unexpected places.

Their droppings are about the size of a pinhead. They’re monotone but can vary in color. Usually, they’re white, black, gray, or brown.

Is Spider Poop Dangerous?

Yes, spider poop is potentially dangerous and needs to be treated like it’s toxic. However, studies have shown that pathogens that spiders ingest don’t get passed on through their droppings. Regardless, use caution and wash thoroughly with soap and water if you handle spider poop.

How Do I Clean Up Spider Poop?

Like most poop, spider poop when it’s fresh, it’s easier to clean. If it’s had a chance to dry, it’s going to take a little more effort to get it up.

Fresh spider dumps can be cleaned up with a rag and water. Dried droppings may leave behind yellow stains no matter how much you try to clean.

Remember that cleaning up the poop doesn’t get rid of the spiders that are creating it. You’ll need to act against these critters if you want to stop the droppings from reappearing.

Keeping things super tidy and destroying every web you see is a good place to start. There are products available to aid with infestations, and professional pest control companies are equipped to handle these situations.

Do Spiders Poop Out Their Webs?

Spiders make their webs with their spinnerets.


No, spider webs are completely different from fecal matter and do not come out of a spider’s anus. Webs come out of a spider’s spinnerets. Proteins that come from silk glands make up a spider’s webbing.

It’s interesting to note that the spiders that build webs to trap prey must deal with thieves. There are species of birds, other spiders, and insects that eat bugs that are trapped in the spider’s web. Some insects will infiltrate a web to eat the spider that owns it.

Do Other Animals Besides Spiders Make Webs?

Yes, other animals can make silk webbing. How they use that webbing can vary widely depending on what critter we’re discussing. Silk production in insects is more common than you may realize.

In almost every insect order there is an animal that creates silk. Centipedes make silk pads for their eggs. Larvae of wasps, moths, flies, bees, and other bugs make silk. Caterpillars make themselves silk cocoons.

Where the silk comes out of other insects is usually much different than how a spider does it. Some do pass their webbing through their anus while others create webbing in their mouths. Spiders can produce different kinds of silks depending on what the situation calls for while most other insects can only produce one kind of webbing.

Insects are not the only creatures that can make silk. There is a mollusk found in the Mediterranean called the fan mussel that uses silk to stick to rocks.

Do Spiders Poop Out Their Eggs?

False widow spider egg sack.

Female spiders lay their egg through their vaginas.

©Chloe Langton/Shutterstock.com

No, spiders do not poop out their eggs. Both male and female spiders have genital organs, though they’re much different than what people have.

Females both fertilize their eggs and lay their eggs through their vaginas. This is where the similarities between the human experience and a spider end.

Spiders put the eggs they lay in an egg sac made of silk to protect them and keep them warm. Some deposit this egg sac somewhere while others will carry it around with them. Females will lay between 150 to 300 eggs on average.

The photo featured at the top of this post is © Fyn Kynd/Flickr – License / Original

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About the Author

Kristen Holder is a writer at A-Z Animals primarily covering topics related to history, travel, pets, and obscure scientific issues. Kristen has been writing professionally for 3 years, and she holds a Bachelor's Degree from the University of California, Riverside, which she obtained in 2009. After living in California, Washington, and Arizona, she is now a permanent resident of Iowa. Kristen loves to dote on her 3 cats, and she spends her free time coming up with adventures that allow her to explore her new home.

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