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Pseudoscorpions

Quick facts

  • Pseudoscorpions are occasionally found indoors.
  • Despite their appearance to true scorpions and ticks, they are NOT harmful to people.
  • Physical removal is the only necessary control. 

How to identify pseuodoscorpions

Pseudoscorpion on a rocky area.
Pseudoscorpion. Credit: Jeff Hahn

Pseudoscorpions are arachnids and are related to spiders, ticks, mites and scorpions.

  • They have oval or teardrop shaped, flattened bodies with two conspicuous pedipalps (pincers). 
  • They are reddish or brown.
  • They are small and have a body length of about 1/5 inch long (about 3/8 inch long when the pedipalps are extended).

When they walk, they often appear crab-like and can move as quickly backward as they move forward.

  • Without their large pincers, pseudoscorpions look like ticks.
  • They are similar to scorpions but lack the long ‘tail’ and stinger that scorpions have

Biology

Pseudoscorpions live in many habitats and are often found in cracks, crevices and similar spaces.  They like high humidity and are found in leaf litter, moss, under tree bark and stones, and in bird and mammal nests.

They enter homes by hitching rides on larger insects (e.g. flies and beetles) or on firewood. They are often found in damp areas, such as laundry rooms, basements and bathrooms but can be seen in any room.

Pseudoscorpions are most commonly seen during spring and summer when it is warm.

What do pseudoscorpions eat?

Pseudoscorpions feed on many types of small insects and other arthropods, including springtails, psocids (barklice and booklice), thrips, small beatle larvae, files, ants and mites. 

  • Many aggressively stalk their prey while others prefer to hide and ambush insects.
  • They have poor vision and use sensory hairs on their pincers to find prey.
  • When a small insect brushes against these sensory hairs, the pseudoscorpion seizes the insect.
  • Poison glands in the pseudoscorpion pincers help to paralyze prey.
  • They inject saliva into the victim and then feed on the liquefied contents.

Pseudoscorpions usually live two to three years. There may be one or two generations in a year.

Are pseudoscorpions dangerous?

A black oval shaped pseudoscorpion with two long pincers on the head
Pseudoscorpions look fierce but are harmless to people
  • Pseudoscorpions are harmless to people and pets.
  • They cannot bite or sting.
  • The poison gland used for feeding is NOT harmful to humans or pets.
  • They are not destructive to food, clothes or property.

What to do when you find pseudoscorpions

You should not see more than one or a few pseudoscorpions indoors.

  • Physical removal is the only necessary control.
  • If possible, slide a piece of paper underneath them and release them outdoors.
  • Insecticides are never necessary.

Authors: Jeffrey Hahn, Extension entomologist and Stephen Kells, Extension entomologist

Reviewed in 2020

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