Book Scorpion
Cheiridium museorum
The Book Scorpion (Cheiridium museorum) is a tiny arachnid measuring only 2-4mm in length, with characteristic pincers but lacking the tail and stinger of true scorpions. These diminutive predators have a flattened, reddish-brown body that allows them to squeeze into narrow spaces, where they hunt mites, booklice, and other small arthropods in human-associated environments.
17
Countries
Photo: iNaturalist: (c) Barry Walter, some rights reserved (CC BY), uploaded by Barry Walter
Taxonomy & Classification
Kingdom
Animalia
Phylum
Arthropoda
Class
Arachnida
Order
Pseudoscorpiones
Family
Cheiridiidae
Genus
Cheiridium
Book Scorpion belongs to the family Cheiridiidae, order Pseudoscorpiones, within the Arachnida class.
Species Profile
The Book Scorpion (Cheiridium museorum) is a tiny arachnid measuring only 2-4mm in length, with characteristic pincers but lacking the tail and stinger of true scorpions. These diminutive predators have a flattened, reddish-brown body that allows them to squeeze into narrow spaces, where they hunt mites, booklice, and other small arthropods in human-associated environments.
The Book Scorpion faces significant threats from habitat loss and degradation, particularly in human-modified environments where it depends on specific microhabitat conditions. Climate change and increased use of pesticides in buildings and storage areas further threaten populations by altering humidity levels and reducing prey availability.
Key Facts
Habitat & Distribution
Inhabits dark, humid microhabitats including old books, paper storage areas, herbarium collections, and dusty corners of buildings, libraries, and museums. Also found under bark, in leaf litter, and among stored organic materials where it hunts small arthropods.
Threats
Habitat degradation in human structures
Pesticide use in buildings and storage facilities
Climate change affecting humidity levels
Disturbance from building renovations and cleaning
Loss of prey species due to environmental changes
Found in 17 Countries
Community Sightings
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Sources & Attribution
How to Cite
IUCN: IUCN (2025). The IUCN Red List of Threatened Species. Version 2025-1. Available at: https://www.iucnredlist.org. doi:10.2305/IUCN.UK.2025-1.RLTS
GBIF: GBIF.org (2025). GBIF Home Page. Available at: https://www.gbif.org
This page: SpeciesRadar (2025). Book Scorpion (Cheiridium museorum). SpeciesRadar: Intelligence for Earth's Biodiversity. Available at: https://speciesradar.org/species/book-scorpion