Pseudoscorpions are small arachnids commonly mistaken for scorpions due to their pincers, but they lack the long tail and stinger of a true scorpion.
They are usually reddish to brown in color, measure about 1/5 inch in body length, and have a teardrop-shaped, flattened body with eight walking legs and two conspicuous pedipalps (pincers).
Though they may appear intimidating, these tiny creatures are generally harmless to humans.
In fact, pseudoscorpions can be considered beneficial, as they feed on various pests such as carpet beetles, ants, mites, and small flies.
Pseudoscorpions, also known as false scorpions, are small arachnids that belong to the same class as spiders, mites, and ticks. Some of their defining characteristics include:
- Two front pincers called pedipalps, used for hunting and defense
- No tail or stinger
- Typically less than 5mm in length
- Over 3,300 species of pseudoscorpions
Pseudoscorpions Vs. Scorpions
When comparing pseudoscorpions and scorpions, significant differences can be seen in their appearances and behaviors. Some key distinctions include:
|Size||< 5mm||9mm – 21cm|
|Number of eyes||2-6||6-12|
There is a wide range of pseudoscorpion species, each with unique traits. For instance:
- Chelifer cancroides, the house pseudoscorpion, is commonly found in human dwellings.
- Cordylochernes scorpioides is a tropical species, known for having the longest pedipalps relative to its body length.
- Neobisium maritimum is adapted to live in coastal habitats with high salinity levels.
These variations showcase the resilience and adaptability of pseudoscorpions as they occupy various ecological niches.
Habitats and Behavior
Pseudoscorpions can be found in various indoor environments, such as basements, bathrooms, and laundry rooms.
They prefer damp areas that provide a suitable habitat for their prey, which includes spiders, ants, springtails, beetles, and flies.
- Common indoor habitats:
- Laundry rooms
When outdoors, pseudoscorpions can be found under tree bark, stones, and in leaf litter.
Diverse environments – from the Canary Islands to Northern Ontario, and from the Jenolan Caves to Maltese Islands – provide suitable habitats for these creatures.
They often occupy gardens, soil, tree hollows, and caves, as well as leaf and pine litter.
- Examples of outdoor habitats:
- Tree hollows
- Leaf and pine litter
Phoresy and Traveling
Pseudoscorpions are known for their unique method of traveling called phoresy. They hitch rides on larger insects, such as beetles and flies, allowing them to travel great distances.
- Phoresy pros:
- Efficient mode of transportation
- Expands their territory
- Phoresy cons:
- Reliance on other insects
- Limited control over destination
|Indoor Habitats||Outdoor Habitats|
|Damp environments||Leaf and pine litter|
In conclusion, pseudoscorpions can be found in a variety of habitats, both indoors and outdoors.
They are not considered dangerous, but rather beneficial as they help control populations of other small arthropods.
Diet and Predation
Pseudoscorpions are tiny, beneficial predators that feed on a variety of small arthropods. These include:
- Mites: often found in dust or soil
- Insects: such as ants, small flies, and booklice
- Larvae: like moth larvae and carpet beetle larvae
As an example, they attack and consume booklice, which helps control their population in homes.
These small arachnids also have their own predators, some of them being:
- Spiders: such as house spiders and cellar spiders
- Beetles: various ground beetle species
- Ants: certain ant species prey on pseudoscorpions
- Flies: some fly species target pseudoscorpions in their infancy
A comparison of pseudoscorpions’ common prey and predators:
|Insects (ants, small flies, booklice)||Beetles|
|Larvae (moth larvae, carpet beetle larvae)||Ants|
Overall, pseudoscorpions play an important role in the ecosystem by preying on various pests and acting as food for other predators.
Reproduction and Mating
Pseudoscorpions are part of the arachnid family, closely related to spiders, scorpions, mites, and ticks.
Their mating process is unique, involving a spermatophore transfer.
The male pseudoscorpion first seeks out a suitable female and performs a courtship dance.
Once the female is interested, the male produces a spermatophore and deposits it on the ground.
He then guides the female over the spermatophore, allowing her to pick it up and fertilize her eggs1.
After mating, the female pseudoscorpion carries her fertilized eggs in a sac under her abdomen.
The offspring are later born as nymphs, which closely resemble smaller versions of adults.
They undergo a series of molts and growth stages before reaching adulthood. Some key features of pseudoscorpions include:
- Oval or teardrop-shaped, flattened bodies
- Reddish or brown color
- Small size, with a body length of about 1/5 inch long2
To make it easier to understand, here’s a comparison table showing some key characteristics of pseudoscorpions and other arachnids:
|Venomous||No||Most species||Some species|
In summary, pseudoscorpions may look intimidating with their pincers, but they are not dangerous to humans.
Their reproduction process is fascinating, utilizing a spermatophore for fertilization.
Offspring are born as nymphs and undergo multiple stages of development before reaching maturity.
Are Pseudoscorpions Dangerous? Pseudoscorpions and Humans
Pseudoscorpions are small arachnids with a body length of about 1/5 inch long (about 3/8 inch long when the pedipalps are extended) and have oval or teardrop shaped, flattened bodies with two conspicuous pedipalps (pincers).
They are not venomous and do not possess poison glands. In general, these creatures are considered harmless to humans.
Infestations in homes are rare, and they do not cause any significant harm to people or their belongings.
Pseudoscorpions are beneficial in controlling harmful insects, as they prey on them.
In their natural environment, they help to keep the population of various pests in check. Here are some key features of Pseudoscorpions:
- Size: Small (around 1/5 inch long)
- Shape: Oval or teardrop-shaped, with pincers
- Harmful insects preyed on: Mites, ants, small flies, and moth larvae
Comparing pseudoscorpions to venomous scorpions, we can see a clear difference in their potential danger:
|Size||Small (around 1/5 inch long)||Larger|
|Stinger||Absent||Present on the tail|
|Venom/Poison||None||Can be dangerous for humans|
|Infestations||Rare||More likely than pseudoscorpions|
In conclusion, pseudoscorpions represent no significant danger to humans and can be considered beneficial by preying on harmful insects in the environment.
So, it is safe to say that these small creatures are not a cause for alarm.
Dealing with Pseudoscorpions
Pseudoscorpions are small arachnids, related to spiders, ticks, mites, and scorpions.
Although they have pincers, they don’t possess the long tail and stinger of a true scorpion.
These invertebrates are typically harmless and beneficial, feeding on pests like carpet beetles, ants, mites, and small flies in their habitat.
Nonetheless, there may be occasions when you need to deal with them.
One of the simplest ways to deal with pseudoscorpions is through physical removal.
Due to their small size (1/16 to 1/8 inch long), use a damp cloth or paper towel to gently pick them up and relocate them outside.
Alternatively, you can use a vacuum cleaner with a hose attachment, ensuring they don’t escape post-cleaning.
Keep in mind, pseudoscorpions prefer damp, dark environments, so they typically won’t pose a threat to you as long as you avoid their habitat.
Although it’s not recommended to kill these helpful creatures, if there’s a persistent infestation, some people may turn to insecticides. However, using chemicals has its pros and cons.
- Effective in controlling large infestations.
- Provides a long-term solution when applied correctly.
- Can harm beneficial arthropods and other invertebrates.
- May pose health risks to humans and pets when incorrectly used.
- Requires the proper identification of the pests, as not all insecticides are effective against pseudoscorpions.
When using insecticides, always follow product instructions closely and ensure proper application to minimize the risk of harm to yourself and other organisms.
With these simple methods, problems with pseudoscorpions can be managed effectively without causing harm to these useful creatures or your environment.
Remember that pseudoscorpions are beneficial predators that help control other pests, and it’s always better to use non-chemical means to address your concerns with them.
Interesting Facts and History
Fossils and Evolution
- Pseudoscorpions are ancient arachnids, with their fossils dating back to over 380 million years ago.
- Many fossils have been preserved in amber, providing insights into their evolutionary history.
- Though similar to scorpions, they lack a stinger and a tail.
Examples of ancient pseudoscorpion species include:
- Ones found in Baltic amber and French amber, dating back to the Eocene Epoch.
- Aristotle mentioned pseudoscorpions in his fourth-century BCE scrolls.
- Pseudoscorpions were featured in Robert Hooke’s 1665 book, Micrographia, a pioneering work in the field of biology.
- New species continue to be discovered, such as the recently found Garypus titanius.
Pseudoscorpion adaptations, structures, and interactions:
- They produce silk from glands in their jaws to create nests or cocoons.
- Their flattened, teardrop-shaped bodies and pincers make them efficient predators of smaller arthropods.
- They are known to hitch rides on larger insects or mammals like bats or livestock for transportation, a behavior called phoresy.
- They are not dangerous, and their small size (usually less than 1/4 inch) makes them difficult to notice.
|No stinger or tail||Possess a stinger and a tail|
|Small in size (less than 1/4 inch)||Larger (can be several inches long)|
|Harmless to humans||Some species can be dangerous to humans|
The fascinating history and characteristics of pseudoscorpions make them a significant subject in understanding arachnid evolution and biology.
They are not dangerous to humans, but their unique evolutionary history, adaptations, and interactions with other species make them an endlessly intriguing topic for study.
Pseudoscorpions are tiny arachnids that resemble scorpions but lack the venomous stinger.
They are harmless to humans and animals and can be beneficial as they feed on other small pests, such as mites, ants, and booklice.
Pseudoscorpions can be found in various habitats, such as leaf litter, soil, caves, and even inside human dwellings.
They are not parasites, but they may hitchhike on larger insects or animals to disperse to new locations.
Pseudoscorpions are not very common, but they are not endangered either.
They are part of the diverse and fascinating world of arthropods and deserve our respect and appreciation.
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about pseudoscorpions. Scroll down to have a look at some of them.
Letter 1 – Pseudoscorpion
My wife found this bug in a stack of her papers. It looks like a tic or spider, but has 10 legs including the pincers on front. All of the pictures of crab spiders I have seen do not include the pincers in the front as this one does.
Any guesses? I have the picture out to a few expert agencies and have heard nothing. ? Thamisus Onustus ? or not ? Western MD pandhandle.
Nice image of the underview of a harmless Pseudoscorpion.
Letter 2 – Harmless Pseudoscorpion
small scorpion looking bug
Location: wisconsin usa
December 25, 2010 9:58 pm
found this bug on the wall in my infant childs room. is there any danger? thanks
Signature: josh kwiatkowski
The harmless Pseudoscorpion if often found in the home where it will prey upon small insects and other arthropods. Since the Pseudoscorpion lacks venom, it is perfectly harmless and you have no cause for alarm.
Letter 3 – harmless Pseudoscorpion
I found this weird bug on my bathroom wall, it freaked me out because I am scared of spiders and it looks like a cross between a spider and a scorpion.
I live in Maine and one of the reasons I love living in Maine because there are no scorpions. Tell me this isn’t a poisonous scorpion bug so I don’t have to move to Alaska or Antarctica.
PS are there any human habitable areas that do not have spiders?
While you are right that Pseudoscorpions look like a cross between spiders and scorpions and spiders, both of whom are related, you can rest easy that they are totally harmless, unless you are a small insect.
They have no poison glands unlike both spiders and scorpions. I doubt there is a place on earth that does not have spiders, except the bottom of the ocean.
Thanks so much for answering my question so quickly! I was a bit worried about those pinchy looking things, good to know they’re harmless.
Letter 4 – Bug of the Month May 2012: Pseudoscorpion
8 legs Plus pinchers?
Location: SE PA, 20 miles west of Philadelphia, 15 miles north of Wilm, DE
April 29, 2012 9:34 pm
Found on shower wall. Body width about 1mm. Shown with 1.75” safety pin, about 1/4” showing. Width of pin about 0.95mm.
Signature: Shower Psycho
Dear Shower Psycho,
You have discovered a Pseudoscorpion, a harmless arachnid that has no venom unlike its stinging namesake. Pseudoscorpions are cosmopolitan in distribution and they are rarely noticed because of their tiny size.
They use their claws to capture prey, and they are beneficial predators. They can also use their claws to attach themselves to larger flying insects that they use to transport them to new feeding grounds, a phenomenon known as phoresy.
Since it is the end of the month, we need to select a Bug of the Month for May, and we are choosing your submission.
Letter 5 – Phoresy with Crane Fly and Pseudoscorpion
Crane Fly w/ Pseudoscorpion
I love your site! We live in 2nd floor apartment in a porous old house in an old mill town in south central Massachusetts. Starlings have found their way indoors more than once. I’m pretty sure the window screens are just to keep the cats in.
So I figure, if we’re going to live with bugs, I should learn their names and habits. Last night while I was brushing my teeth I noticed a crane fly nearby at eye level so I leaned in for a closer look. That’s when I saw the pseudoscorpion, hitching a ride(?).
I’m not sure how it’s hanging on there, but it was flexing its free legs to no apparent purpose. The crane fly flew to several spots with the little guy hanging on before landing where I couldn’t see them anymore.
Before becoming a regular reader of your site I might have said I saw a mosquito hawk with a OMG-what-is-that-thing on it. But as is it, I knew just who they were. Thanks so much for both the information and the entertainment.
We are thrilled to post your photo of Phoresy with a Pseudoscorpion hitching a ride on a Crane Fly.
Letter 6 – Phoresy: Pseudoscorpion hitches ride with Spined Oak Borer
cerambycid with pseudoscorpion attached
Thought I’d send a couple of pics I think are interesting. I took some photos of what I think is a species of cerambycid that has a pseudoscorpion attached to it. Thought you might want to see them. Oh, and I always forget to add this, I took these in Fort Gordon, Georgia about 2 weeks ago.
We wish we could tell you exactly what species of Wood Boring Cerambycid you have in your photo. We will seek the assistance of Eric Eaton. We can tell you that the Pseudoscorpion is hitching a ride with the flying Cerambycid, a technique known as Phoresy.
Welcome back! Coincidentally, I just visited the site today, after ignoring it while you were away. LOL! Hope you had fun in Ohio. I miss the lush vegetation out there….
The cerambycid is probably the “spined oak borer,” Elaphidion mucronatum, named for the pair of spines at the tip of each wing cover. Cerambycids in general seem to be favorite modes of transport for pseudoscorpions.
Confirmation: With Different Common Name(6/12/2008)
The long horn in question looks like the “Spined Bark Borer” Elaphidion mucronatum due to the long femoral spines which sorts it out from Parelaphidion spp. and a longer spine on the 3rd antennal segment.
Hard to tell for sure due to angle of the photo. Seems to be to robust to be an Anelaphus spp. I hope this helps. Keep up the good work as always.
Letter 7 – Pseudoscorpion
what is this?
Found this on my windowsill in my kitchen in Georgia. What is it? I thought perhaps it was a baby scorpion?? For an idea of size, one of the “arms” is between 1/8″ and 1/4″. Any idea? Please reply!
The Harmless Pseudoscorpion is one of our most common identification requests.
Letter 8 – Pseudoscorpion Carnage in Germany
Odd German bug…
I’m currently studying abroad in northern Germany, in the vicinity of Bremen, and I did a search on the internet in hopes of identifying a bug I just saw. I found your website, and I was wondering if you could help me. I’m especially interested to know whether or not it’s harmless.
I’m afraid I squished it in fear before I could take a picture of it while it was alive. I’ve attached a couple of pictures of it dead, though… (And I’m sorry I squished it, it’s just that I have a skin condition that causes me to react negatively to ALL bug bites. Even mosquito bites cause baseball sized reactions on me.
If it doesn’t bite or sting, I remove it nicely from my house. My host parents here even taught me how to catch flies without hurting them.) In case the picture doesn’t tell all, I will describe it… It was really really tiny, to begin. It dropped onto my hand as a fly buzzed around my hand (at first I thought it was fly poop, that’s how small it was).
When I looked closer, it appeared to have the body shape of a tick (though it squished much easier than a tick), and the body was brown. It’s legs were tiny and comparable to a typical beatle’s legs. Attached to the front end of it, by the head, where these long stinger like things. Two of them.
One on each side, extending out in front of the bug. They were more of a reddish brown color, and looked very much like scorpion tails. These scorpion-like stingers were very large in comparison to the bug, and I would say they were three quarters the length of the body.
If you can identify this bug, I would really be interested to know more about it. And feel free to publish my photos (though they’re not the greatest). Thank you!!
There was no need to kill the harmless Pseudoscorpion. These fascinating creatures have a nearly worldwide distribution. They sometimes hitch rides on flying insects, a phenomenon known as Phoresy.
Letter 9 – A Spoonful of Pseudoscorpion
found in cereal
Dave and Wendi
Hi Dave and Wendi,
I wasn’t aware that manufacturers were adding protein to dry cereal. Often, grain products become infested with pantry beetles or meal moths, and if they sit on the shelf too long, can be purchased that way.
Most homemakers know what it is like to have kitchen infestations. Your situation is a little different though. The harmless Pseudoscorpion is actually a predator. How it got in the box is a mystery, unless there were other living morsels there to attract it. Did you enjoy your morning Spoonful of Pseudoscorpion?
Letter 10 – Pseudoscorpion attacking Pine Sawyer antenna? Nope: Phoresy
What could this be?
The attached photos are of some type of insect or arachnid that was on one of the antenna of a white spotted pine sawyer. We thought it was a scorpion but when we got a close up of it, it seemed to look more like a tick or mite of some sort.
Maybe you can help identify what it is. My co-workers and myself are interested to know what it is,as we work for a pest control company.
Thanks in advance for your help,
You have photographed a harmless Pseudoscorpion. they are known to prey on insects much larger than them, but I think the Pine Sawyer might have proven to be too much for the wee guy. Thanks for the photos.
We thought origionally that it was a scorpion of some sort but the missing stinger and tail threw us off thank you for helping us identify our mystery bug. I will deffinatly be visiting your site again as sometimes we get pests that we are unable to identify on our own.
Ed. Note: Eric Eaton just provided the following fascinating information. “P.S. Oh, that pseudoscorpion was not ‘attacking’ that longhorn beetle’s antenna, it was hitching a ride:-) That is the way they get around (just glom onto something that can fly). It is called ‘phoresy.’ “
Letter 11 – Drawing of a Pseudoscorpion
Spider, Tick, Tailless Scorpion, or something else???
Location: Enfield, New Hampshire
November 17, 2010 2:59 am
I have found a bug in my home that I very rarely find and dont know what it is??? Today is the 3rd time I have seen this species since I lived here since 1994. I have found this bug mostly in dark places like the floor of our broom closet, and once fell off a box of spaghetti and onto my stovetop.
This time however I was making our bed and say him and got excited while my wife was disgusted with a bug in our bed. I found a small zip lock bag and a piece of paper and scooted him into the bag. His attitude towards this was defensive and he always turned in the direction of the edge of paper and he reminded me of a scorpion, but without a tail.
I found my wifes digital camcorder and went to go back to the ziplock bag to get a snapshot and the ziplock bag had a broken seam on the side so he escaped =( I would really like to know what type of bug he is and if he is harmless or not.
When observing these guys in their habitat they are usually forraging in dust and using their s corpion like pinchers to bring stuff to their small mouth. So I dont know if mites have pinchers if this is what he is. Really bummed that he got loose. i have a stereo microscope and was hoping to get a nice picture of him. If I went to try to find them, i can never find them.
I only find them by accident, so I am thinking their population within my home is very small. I drew a picture of what i found and can supply more info if needed. Added a dime to photo to give scale or the bugs size in lower left. Larger picture i drew to show pinchers and body features. He also has 8 legs + the 2 pinchers i believe.
Signature: Thanks, Dave
Thanks to your excellent drawing, there is little doubt in our mind that you have found a harmless Pseudoscorpion.
Letter 12 – Is it a Pseudoscorpion? or is it Art????
What is this bug?
Location: Brookings, SD
June 22, 2011 9:20 pm
I have only found a couple of these bugs in my house but there may be a lot more that I am not noticing due to their tiny size. What is it? Is it harmful to my house or anything? Thank you.
Signature: Chris Williams
We absolutely love your photo of a Pseudoscorpion. It is a beneficial predator that will not harm you or your home. It has no venom.
Letter 13 – Phoresy: Pseudoscorpion hitches ride on House Fly
Pseudoscorpion Holding onto House Fly
Location: Southwest Indiana
August 18, 2011 11:58 am
I just want to let you know how much my family and I appreciate your site. After searching, I never fail to identify the bug I am looking for.
I am including pictures of what I believe, thanks to your site, is a Pseudoscorpion hitching a ride on a house fly. He was actually holding onto the fly’s mouthpiece, much to the fly’s dismay. The fly would constantly stop and try to pull the little guy off.
Afterwards, we released the fly and his hitchhiker out in the garden. Thanks again.
Thanks for the compliment. This phenomenon of hitchhiking is called Phoresy and Pseudoscorpions are quite good at it.
Letter 14 – Phoresy: Pseudoscorpion hitches ride on Weta in New Zealand
Small insect on antennae
Location: Wellington, New Zealand
March 16, 2012 7:59 pm
Hiya, I’ve got this photo of a weta and it was only after downloading it from my camera that I noticed there was a tiny little insect attached to the weta’s antennae. Can you tell me what it is? It’s got claws like a crab or scorpion. This was taken in Karori, Wellington, NZ in my front garden. Lots of stones and trees.
Signature: Thank you, Angela
You have taken a marvelous photograph. First we must say that we love your New Zealand Wetas. They are amazing insects. The hitchhiker is a harmless Pseudoscorpion.
The act of using another creature for transportation purposes is known as phoresy, and we have several interesting images of Pseudoscorpions engaging in phoresy on our website, including a House Fly, an Ichneumon, a Cranefly and a Longicorn. Thank you again for your wonderful photograph.
Letter 15 – Jewel Beetle with Pseudoscorpion “hitchhiker” from Costa Rica
Subject: Green & Black Beetle
Location: near Golfito Costa Rica
July 26, 2013 5:11 am
This green and black beetle would show up off and on during our recent visit to Costa Rica. I found it quite striking. In a few picture it has a crab-like bug attached to it. Do you know more about these two.
Signature: Ocho Verde Wildlife
This colorful beetle is a Metallic Borer Beetle or Jewel Beetle in the family Buprestidae. The wings are used to make jewelry by many indigenous groups in South America and modern jewely designers have continued that tradition. We are sorry, we haven’t the time right now to research the species.
Letter 16 – Pseudoscorpion found near Mount Everest!!!
Subject: Wow what’s this bug?
Location: Nr Mount Everest
February 26, 2014 1:31 am
My friend found this bug in his bed in nepal.
It’s like a bed bug with scorpian arms!
I have done a little looking online but can’t find anything quite like it!
Think it was discovered near mount everest or when they were going to base camp.
Otherwise it was somewhere else in nepal.
Sorry the photo sin’t great.
Signature: Happy Bunny
Dear Happy Bunny,
This is a harmless predatory Pseudoscorpion, and its location near Mount Everest has piqued our interest. We normally get photos of Pseudoscorpions because they are found in homes and dwellings, and we wonder if they have adapted through the years to benefit from a close association with humans by preying upon pests that trouble us, like Bed Bugs.
Thank you so much for looking at that for me 🙂
I have told my friend what it is, he will be pleased as it freaked him out a bit!