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Nature

Crab Spider

What is crab spider?

· Emily Grant

Key facts

Family Thomisidae[1]
Distribution Worldwide[1]
U.S. species About 125[1]
Movement Often walk sideways or backward[1]
Hunting method Ambush predators that wait in hiding[1]

Crab spider is a common name for spiders in the family Thomisidae, known for their crab-like shape and sideways walking. They are ambush predators that do not spin webs.

Context

Crab spiders belong to the family Thomisidae and are found worldwide, with about 125 species in the United States [1]. They are named for their crab-like shape and often walk sideways or backward [1]. Unlike web-building spiders, they are ambush predators that wait in hiding for prey [1]. Many common species live on the soil surface, in leaf litter, or under bark [1]. Some, like the Goldenrod Crab Spider, can change color to match their surroundings [3]. The name 'crab spider' may also refer to spiders from other families, not just Thomisidae [2]. They are sometimes called 'flower spiders' because they often hunt on flowers [2]. In contrast, wolf spiders are active hunters that chase prey on the ground.

Documented claims

  • Crab spiders are named for their crab-like shape and the way many can walk sideways or backward. [1]
  • They are typically ambush predators that do not spin webs as snares. [1]
  • The name 'crab spider' is often linked to Thomisidae, but may also be used for spiders from other families. [2]

Related

Crab AppleBada har 'crab' i namnet men ar helt olika organismer; en lasare som undrar over namnet kan vara nyfiken pa andra 'crab'-namn.

Questions and answers

Are crab spiders in Canada?

Crab spiders are found worldwide, including in Canada [1].

Is the spider crab poisonous?

Crab spiders are not considered dangerous to humans; they are not known to be poisonous [4].

Are UK crab spiders poisonous?

Crab spiders in the UK are not poisonous to humans [4].

What is the #1 deadliest spider?

The title of deadliest spider is often given to the Sydney funnel-web spider, but crab spiders are not among the deadliest [4].

Sources

  1. Crab spiders (Araneae: Thomisidae) — entnemdept.ufl.edu (retrieved August 3, 2026)
  2. Crab Spider: Family Thomisidae - Urban IPM — urbanipm.montana.edu (retrieved August 3, 2026)
  3. Ground Crab Spiders | Missouri Department of Conservation — mdc.mo.gov (retrieved August 3, 2026)
  4. Crab Spiders: Identification, Habitats & Bites — terminix.com (retrieved August 3, 2026)

Sources last checked August 3, 2026. · More in Nature