More Urban Species: House Pseudoscorpion

[urbpan]

House Pseudoscorpion  Chelifer cancroides

My apologies for the blurry photo.  The animal pictured has a body length of about three millimeters, and the camera I used was at its limit for macro photography.  Pseudoscorpions are tiny predatory arachnids, resembling scorpions but differing in having no stinging tail.  Instead they have venom glands in their pincers; these are much too small and weak to hurt humans or cats. 

The pseudoscorpion most often found inside houses and other buildings is Chelifer cancroides the house pseudoscorpion or book pseudoscorpion (or "book scorpion").  They prey on other domestic arthropods, including booklice, and may be found in old paper goods pursuing these creatures.  The house pseudoscorpion is found all around the world in the great indoors.  Some 400 other species are found in a variety of habitats, including one that startled the heck out of my brother and I as we camped in the Utah desert.  "Hey look a scorpion," is never a comforting thing to say to a fellow camper.  But when it turns out to be a harmless pseudoscorpion, that's okay.

Edited to add: Alexis took a really nice picture of one back in March:


Further reading and looking:
Penn State Entomology dept. page on this animal
Much better pictures than mine, from bugguide.net

Comments

[jess-d-ripper.livejournal.com]

I love these guys! They're so neat.

[zipotle.livejournal.com]

I love those things!

[batwrangler.livejournal.com]

We have them in New England?

[urbpan.livejournal.com]

Indeed. The top specimen was collected in Massachusetts, the bottom one in Vermont.

[batwrangler.livejournal.com]

Wicked cool! I must try to find one in NH.

[buboniclou.livejournal.com]

Benign, maybe, but anything with that shape still gives me the jibblies.

Except for lobster.

[ndozo.livejournal.com]

I'm with batwrangler. In New England?!?

[urbpan.livejournal.com]

In New England. Indoors.

I'm sorry I squished it...

[(Anonymous)]

I thought a fruit fly was next to me on the table so I picked up a book and hit the fly. Then this little tiny thing with pinchers and a rounded butt (a Pseudoscorpion) came skuttleing out I was shocked (and grossed out). I have done a bit of reading now and I wish I would have scooped it up and put it in my garden. I've lived in western Washington all my life and I have never seen one before. Lol, another reason why kill and ask questions later just doesn't work.

I just found one in my tub...

[(Anonymous)]

What should I do with it? Put it outside?! It's in a cup right now... I live in VT...

Re: I just found one in my tub...

[urbpan.livejournal.com]

Whatever you want. Tubs often are too slippery for some creatures to crawl out of. You can remove the bug, but the conditions that attracted the bug will remain.

pseudoscorpions

[(Anonymous)]

Okay, I had never seen one in all my 37 years living up until about a year or two ago when i was freaked to find a living one in my Jello packaging... I did not eat the Jello....it has taken me that long to find out what they are.... thank you! I just came across another one today and was wondering what it was... I thought at first i had gotten a deer mite. it was a little disconcerting to find it floating in the tub with me..... need i say more...but it brought back the curiosity. So again thanks, i feel much better about it living in my home and it will not freak me out anymore. BTW you mentioned it was not a danger to cats, are there any pets they can be a danger to? I have a rabbit and gerbil.

Re: pseudoscorpions

[urbpan.livejournal.com]

No, they would only be a danger to a pet mite or springtail.

Just found one

[(Anonymous)]

I panicked at first, because I thought it was a tick, I already have lyme disease, and live in Illinois. Now I do not panic easy, I carry non-poisonious creatures out of the house all the time. It was already dead, I found it in the shower, and luckily I could make out the pinchers. Then googled your column. I will be sleeping easier tonight.