arachnid: Quick Facts

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Facts

Also Known As	Arachnida

Photos and Videos

A brown Buthus scorpion with its tail arched over its back and stinger raised, standing on a piece of wood.

Illustration showing eight types of mites and ticks, each labeled with their common and scientific names, including tropical rat mite, Opilioacarus texanus, Holothyrus legendrei, fur mite, black-legged tick, soil mite, itch mite, and American house-dust mite.

Chart titled Diversity of arachnids comparing a Silurian fossil scorpion and 11 living groups, including spiders, scorpions, mites, daddy longlegs, sunspiders, whip scorpions, and false scorpions. Illustrations show their varied forms and typical size ranges from 0.1 millimeters to 210 millimeters; fossil anatomy labels identify pincers, pedipalps, legs, and body sections.

Tailless whip scorpion

Illustration of a ricinuleid, a small arachnid in the order Ricinulei, showing its segmented brown body, eight jointed legs, and distinctive shield-like structure on its back.

Illustration of a palpigrade arachnid (order Palpigradi), showing its small, segmented body, eight legs, and a long, thin, bristle-covered tail. Size range is 0.8 to 2.6 millimeters.

Illustration of a daddy longlegs, or Opiliones, showing its small, rounded body and extremely long, thin legs, characteristic of this arachnid order.

A detailed top view of a schizomid arachnid (order Schizomida), showing its segmented, striped abdomen, elongated legs, and small pincers, measuring about 5 to 7 millimeters long.

A brown nursery web spider from the Pisauridae family clings to green leaves while carrying a round white egg sac beneath its body.

A man sleeps with his mouth open on a bed, while a large spider sits on the pillow near his hand.

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Watch a water spider create its underwater house

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Topics

daddy longlegs spider scorpion acarid tick mite sunspider false scorpion whip scorpion tailless whip scorpion reptile fish insect Bird mammal crustacean amphibian mollusk sea spider Animal social behavior

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Green tree python snake (Chondropython viridis) in a rainforest.

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Sea otter (Enhydra lutris), also called great sea otter, rare, completely marine otter of the northern Pacific, usually found in kelp beds. Floats on back. Looks like sea otter laughing. saltwater otters

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