Pseudoscorpions are fascinating arachnids, often mistaken for miniature scorpions due to their similar appearance. Despite their name and appearance, these creatures differ significantly from true scorpions, particularly in the absence of a tail and stinger.
These tiny predators are found in various habitats and typically measure between 1/16 to 1/8 inch in length. Their primary diet consists of small insects, mites, and larvae, which they capture using their pincers. As they feed on common household pests such as carpet beetles, ants, mites, and small flies, pseudoscorpions often prove beneficial to humans.
Thankfully, pseudoscorpions are harmless to humans and lack the ability to bite or sting. Their tiny size and weak pincers render them unable to penetrate human skin. Instead, they serve as helpful allies in controlling various unwanted pests.
What Are Pseudoscorpions
Pseudoscorpions are arachnids, making them relatives of spiders, ticks, mites, and scorpions. A few key characteristics of arachnids include:
- Jointed appendages
- Segmented body
Distinct physical features of pseudoscorpions include:
- Oval or teardrop-shaped flattened bodies
- Reddish or brown color
- Body length of about 1/5 inch long (about 3/8 inch with extended pedipalps)
- Two conspicuous pedipalps (pincers)
Key Differences Between Pseudoscorpions and True Scorpions
Pseudoscorpions and true scorpions vary in several aspects, as outlined in this table:
|Smaller – 1/5 inch body length
|Larger – Typically 2-4 inches long
|Lack large, segmented tails
|Possess long, segmented tails with stingers
|Harmless to humans, lack venom
|Potentially dangerous, venomous
|Common inside homes, in leaf litter or under stones
|Common outside, in deserts, forests, and grasslands
|Mostly feed on small insects, mites
|Feed on insects, smaller scorpions, spiders
By understanding these key differences, we can better identify pseudoscorpions and distinguish them from true scorpions in their distinct habitats and characteristics.
Pseudoscorpion Behavior and Habitat
Feeding and Prey
Pseudoscorpions are tiny predators that feed on various small arthropods, such as:
- Small insects
- Carpet beetle larvae
Although they have pincer-like pedipalps, they are not venomous, and they use their chelicerae to inject digestive fluids into their prey, liquefying the internal organs, which they then ingest.
In pseudoscorpions, mating involves careful courtship rituals where the male deposits a spermatophore (a package containing sperm) on a substrate and guides the female to it. This process typically occurs during warmer months, such as spring and summer.
These small arachnids prefer damp and humid environs, where they can be found in a variety of habitats both outdoors and occasionally indoors:
- Tree bark
- Leaf litter
- Tree hollows
- Intertidal zones (e.g., Canary Islands)
- Laundry rooms
Pseudoscorpions often hitch a ride on larger animals such as rats or beetles through a process called “phoresy” to move from one location to another.
|Soil, moss, tree bark
To summarize, pseudoscorpions are interesting arachnids with unique feeding and mating habits. They can be found in various outdoor habitats, as well as some indoor locations when seeking suitable moisture and prey.
Benefits and Dangers of Pseudoscorpions
Are They Harmless or Dangerous?
Pseudoscorpions are generally considered harmless to humans. They lack the stinging tail of a true scorpion and their mouthparts, while modified for venom injection, are too small to pierce human skin. Examples of harmless pseudoscorpions include:
- Chelifer cancroides (the common house pseudoscorpion)
- Other small species that live beneath tree bark
Pseudoscorpions are primarily predators of small invertebrates like ants, small flies, and thrips. However, they are not known to attack mammals, and incidents of pseudoscorpion biting humans are extremely rare.
Role in Pest Control
Pseudoscorpions are beneficial to humans, as they play a vital role in controlling pests. Their diet consists of:
- Small flies
- Other small insects
Utilizing their pincer-like claws and poison glands, pseudoscorpions inject venom into their prey which aids in subduing and digesting them. This makes them a natural form of pest control within gardens, homes, and other ecosystems where they reside.
Pseudoscorpions may occasionally infest indoor areas, as they sometimes wander into homes by accident. However, they do not typically pose a significant issue, as they are not known to damage property or harm inhabitants. Common indoor pseudoscorpions are:
- Chelifer cancroides (also known as book scorpions)
Infestations can be addressed with physical removal, and measures to prevent future entry, such as sealing any cracks or gaps in walls and windows. It’s important to note that indoor populations of pseudoscorpions may in fact be beneficial, as they can help control other pest species that might be present in the home.
Comparison table: Pseudoscorpions vs True Scorpions
|Up to 20 centimeters
|Venom in claws, unable to pierce human skin
|Venomous stinging tail
|Danger to Humans
|Potentially harmful depending on species
|Pest Control Benefits
|Beneath tree bark, homes, gardens
|Deserts, forests, grasslands
In conclusion, pseudoscorpions are harmless arachnids that play a vital role in pest control. While they may occasionally infest indoor spaces, they pose no danger to humans and can even help keep other pest populations in check.
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.
Letter 1 – Pseudoscorpion
Eight Legs + Two Claws — Insect?
I love your site. After my grandmother was attacked in Arkansas by a very aggressive, female, Dobson fly, my love of insects has only increased. Your site has provided hours of fantastic information and wonder. I finally found out what a house centipede was. But now I have an unknown, which I submit with pictures. I live in Minneapolis in an apartment building. Today I found crawling on my wall a fairly small, maybe 3-4 mm long, eight legged creature with an additional two large crab-like claws in the very front. Its body is very similar in shape and coloring to a cockroach nymph. The creature carries its claws in front of its body in much the same way a crab would, slightly extend and slightly raised. Additionally, the creature uses its claws in much the same way a crab would. It seems to regularly bring a claw to its mouth and “taste” what’s on the claw. Please review my photos and tell me what you think. I can’t seem to find anything on the net that even hints and what this might be. Thanks a million Bug Man!
PS – On closer inspection it appears this creature has no antennae.
This is not an insect, but an Arachnid. It is a harmless Pseudoscorpion. Pseudoscorpions are quite harmless, but they are fierce predators if the prey is small enough for them to capture. They are known to catch and eat house flies much larger than themselves. We get submissions of Pseudoscorpions from around the world.
Letter 2 – Pseudoscorpion
unidentified bug in the tub
We found this bug in the bathroom in the evening. We live in Vermont and are in the middle of winter. Please help in identifying. Thank you
North Ferrisburg, VT
Future readers will have no problem identifying the tiny and harmless Pseudoscorpion thanks to your photo. Pseudoscorpions prey on insects and spiders and are often found in bathrooms.
Letter 3 – Pseudoscorpion
pics of pseudoscorpion
We just moved to CO last May. A couple of months after moving in I found what I thought was a tick on my shirt. When I brought it into the bathroom to flush it-it started waving these little arms around! I took some pics and put the skeevy little thing in a cup so I could look it up. Your website is INSANE. I found out that I have a useful little thing called a pseudoscorpion! I let it go outside. A couple of nights ago I found another one while taking a shower. I took some better pics and put it in our spare room instead of outside. It’s too cold out right now, and if it’s in here it’s probably eating stuff I don’t want to know about anyway. I thought you might like to see them so here they are!
Kim K. in Colorado Springs
Thank you Kim,
Your photos are quite beautiful.
Letter 4 – Pseudoscorpion
I found this bug in my bathroom on the ceiling. Its rather scary looking, it reminds me of a scorpion but seeing as I live near Toronto I am sure it is not a relative. It is very tiny, in the pictures it is next to a pin. Could you please tell me what it is and if it is harmful. It is the only one I’ve seen so far, I’m hoping there will not be anymore. Thanks
Have a wonderful day!
This is a Pseudoscorpion and it is totally harmless.
Letter 5 – Pseudoscorpion
Found this could you please help?
Found this bug in the bathroom a couple of days ago. Could you please help me to find out what it is? It has a round body, black head, 8 legs and 2 claws. thank you if you can help me
What a scary photo of a harmless Pseudoscorpion.
Letter 6 – Pseudoscorpion
Another picture for you
Thanks to your site, I identified this insect immediately. Here is a fairly sharp image, if you want something larger and sharper than most of the pictures you have.
Sharper photos of Pseudoscorpions are great, but we reduce the size of images to help conserve bandwidth on the internet. Pseudoscorpions are Arachnids, not Insects.
Letter 7 – Pseudoscorpion
Hey, Just wanted to write and say I love your site. I turned to it today because I found this tiny little bug on my shorts. At first I thought it was a scorpion, then a tick with huge pinchers. So I took a pic and found your site. I live near Orlando FL. I noticed my Pseudoscorpion has a dot on its back and it seems to be a lighter color than others. I let him go after the photo shoot. Thought you might like to post this pic too. Thanks again!!
Thanks for your letter confirming that people actually identify their creatures using our site. Since about 95% or our queries already have identifications posted, it seems most people don’t bother to go past the contact link. Often the object of their desire is prominently featured on the homepage and they miss it.
Letter 8 – Pseudoscorpion
Can you help in identifying these small spiders we find occasionally in our home in Ottawa Canada ,We may see only two or three a year usually in the Spring , But cannot find a match for them on any of the web sites ,I see similar ones ,But nothing like the one in this attachment, Which is about 1 mm across ,Any help would be appreciated .
Had you merely scrolled down our homepage, you would have seen photos of another Pseudoscorpion. We have an entire page devoted to these interesting and harmless creatures.
Letter 9 – Pseudoscorpion
I found this little guy running around my bathroom ceiling this morning. I have never seen anything like it before. The body was flat and thin and I couldn’t tell if the appendages at the front were claws, stingers, or just oddly shaped antennae. I live at the northern edge of Michigan’s Upper Peninsula. Thanks!
12 minutes later:
Ooops, found it, pseudo-scorpion. I should have fully browsed before emailing you. Thanks for the great site!
We are glad our site was helpful.
Letter 10 – Pseudoscorpion
Strange Bug in the Bathroom
Found this bug in my bathroom cant find a picture of him anywhere mainly cause I don’t know what type of bug to be looking for it was so small it was hard to get a good picture of it but this was the best one.
This is a Pseudoscorpion, and it is harmless. It is actually beneficial as it will devour other intruders less welcome than itself.