Spiders

Spiders at a glance

Need to know

• Spiders are found on every continent except Antarctica.
• All spiders are predators, feeding mainly on insects.
• Some species can go years without food.
• Spiders produce silk, used for webs, egg sacs, and more.
• Only a small fraction of spider species have venom dangerous to humans.
• Jumping spiders have among the best vision of any arthropod.

About the Spiders

Spiders (order Araneae) are one of the most successful groups in the animal kingdom, thriving on every continent except Antarctica. With over 51,000 described species, spiders have evolved to fill nearly every terrestrial habitat, from rainforests to deserts, and even in human homes. Their success is largely due to their specialized silk production, effective predatory adaptations, and remarkable diversity of forms and behaviors.

While spiders are often feared due to misconceptions about their venom, the vast majority are harmless to humans and vital for healthy ecosystems by controlling insect populations. Species range dramatically in size, from minuscule sheet-web weavers only millimeters across to the imposing Goliath Birdeater tarantula. Each species exhibits unique web-building techniques or hunting strategies, feeding habits, and reproductive behaviors, making spiders endlessly fascinating to scientists and naturalists alike.

Physical characteristics

Size: From 1 mm to 30 cm (leg span). Weight: Typically 4 mg to 175 g. Lifespan: Most 1-2 years, some tarantulas up to 25 years.

• Eight legs
• Two distinct body segments (cephalothorax and abdomen)
• Eight or fewer eyes, often arranged in rows
• No antennae or wings
• Fangs (chelicerae) adapted to inject venom

Notable species

• Goliath Birdeater (Theraphosa blondi) — Not Evaluated. Tropical rainforest floor, burrows under logs and debris Regions: Amazon Rainforest, Northern South America, Guiana Shield, Rainforests of Venezuela, Brazilian Amazon.
• Black Widow (Latrodectus mactans) — Least Concern. Woodpiles, sheds, under rocks, and debris in temperate areas Regions: Southeastern United States, Central America, Caribbean, Northern South America.
• Sydney Funnel-Web Spider (Atrax robustus) — Not Evaluated. Moist forest floors, under rocks or rotting logs Regions: Sydney region, New South Wales, Eastern Australia, Blue Mountains, Illawarra.
• Golden Silk Orb-Weaver (Trichonephila clavipes) — Not Evaluated. Moist forests, woodland edges, gardens Regions: Southeastern United States, Central America, South America, West Indies.
• Jumping Spider (Phidippus audax) — Not Evaluated. Grasslands, gardens, forests, human dwellings Regions: North America, United States, Southern Canada, Mexico.
• Brazilian Wandering Spider (Phoneutria fera) — Not Evaluated. Tropical forests, banana plantations Regions: Amazon Rainforest, Northern South America, Ecuador, Peru, Brazil.

Habitat and range

Original range: Likely evolved in regions corresponding to modern-day Eurasia during the Devonian-Carboniferous periods.

Current distribution: Nearly worldwide, on every continent except Antarctica.

Preferred environments: Forests, Grasslands, Deserts, Wetlands, Urban areas, Caves, Rainforest canopies

Regions: North America, South America, Europe, Africa, Asia, Australia, Southeast Asia, Central America, Arctic tundra

Where to see Spiders

• Amazon Rainforest — Rainy season (December to May). Look around forest floor debris or in tree hollows for large tarantulas.
• Australian bushland — Spring and summer. Sydney Funnel-Web spiders can be seen near moist ground after heavy rain.
• Backyards and gardens worldwide — Spring, summer, and autumn. Look under leaves, rocks, and outdoor furniture for orb-weavers and jumping spiders.
• Tropical forest understories — Year-round. Hunt for golden orb-weaver webs along trails and open clearings.

Behavior and diet

Diet: Primarily insects and other small arthropods; some large species may eat small vertebrates (frogs, lizards, birds).

Social structure: Mostly solitary, though a few species exhibit temporary social or communal behavior.

Communication: Rely on vibrations (especially in webs), chemical signals (pheromones), and visual displays (notably jumping spiders).

• Build intricate webs for capturing prey or courtship displays (orb-weavers, sheet-web spiders)
• Visual courtship dances by males (jumping spiders)
• Some species actively hunt without webs (wolf spiders, jumping spiders)
• Autotomizing limbs to escape predators

Interactions with other animals

• Insects (flies, mosquitoes, beetles, moths) (prey): Most spiders are voracious predators of insects, helping control their populations.
• Birds (predator): Some birds prey regularly on spiders.
• Ants (predator/prey): Ants may kill and eat spiders; some spiders mimic ants to avoid predation.
• Parasitoid wasps (predator): Certain wasps paralyze spiders to lay eggs on them for larvae to consume.

Conservation

IUCN Red List status: Not Assessed (overall); most species Least Concern

Threats

• Habitat destruction and fragmentation
• Pesticide use
• Climate change
• Pet trade (for large exotic species)

Conservation efforts

• Habitat preservation in parks and reserves
• Environmental education and public outreach
• Legal regulations on trade and collection of rare species

How to help

• Support habitat conservation projects
• Reduce pesticide use in gardens and agriculture
• Learn to appreciate and safely coexist with spiders
• Report sightings of rare or invasive species to scientists
• Avoid purchasing wild-caught exotic spiders

Spiders facts for kids

Spiders are hunters with eight legs that spin silk webs to catch food. There are thousands of different kinds, and most spiders are not dangerous to people. Spiders help us by eating lots of bugs!

• Spiders have eight eyes, but some can't see very well!
• Many spiders can make their own homes from silk.
• A giant Goliath Birdeater's legs can be as long as a dinner plate.
• Spiders walk with four legs on each side of their body.
• Some jumping spiders can leap over 50 times their own body length.

Did you know? Did you know? All the spiders in the world eat hundreds of millions of tons of insects each year—that's more than all people eat in meat and fish combined!

Watch & learn

• The Wonders of Spiders: Masters of Silk and Survival — BBC Earth. BBC Earth's animal documentaries include breathtaking footage of Araneae crafting webs, hunting prey, and fascinating insights into their unique adaptations. The narration and visuals capture spider behavior in ultra-high definition.
• World’s Deadliest Spiders: Venom, Predation, and Life — National Geographic. National Geographic's deep dives into arachnid life include stunning scenes of spider hunting strategies, venom use, and survival in various environments, making it both educational and thrilling.
• Amazing Spider Engineering: Webs and More — Smithsonian Channel. This documentary explores the architecture of spider webs, silk production, and the incredible engineering feats of different spider species. High-quality macro footage reveals details the naked eye can't see.
• Into the World of Spiders: Nature’s Tiny Predators — PBS Nature. PBS Nature delves into the lives of spiders, covering their critical role in ecosystems, diversity among the order Araneae, and their ingenious predatory tactics, in beautifully filmed segments.
• The Secret Life of Spiders: Camouflage, Mimicry, and Survival — BBC Earth. Focuses on the adaptive behaviors of spiders, highlighting spectacular cases of camouflage, mimicry, and survival strategies in hostile environments. Includes rarely seen spider species.