Woodlouse assassin and protective mum. This feisty arachnid is perfectly equipped to take on tough customers – and other spiders won’t mess with it either.
Red spiders are a common sight in homes, gardens, forests, and nature. With over 30,000 spider species in the world, many of them exhibit some red coloration. From bright crimson red to dark burgundy, red spiders display a range of beautiful and varied colors and patterns. While the sight of spiders makes some people squeamish, learning more about them can help overcome fear and appreciate their unique features. This guide covers key facts, identification tips, and information about 32 of the most common red spiders in North America.
Why Are Some Spiders Red?
Red coloration in the spider world can serve different purposes depending on the species. Some key reasons include
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Camouflage – Red spiders may blend in with red leaves, flowers, rocks or soil in their natural habitats Their color helps them hide from predators and sneak up on prey undetected
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Mimicry – Some red spiders mimic the appearance of other red insects like ants or wasps to avoid predation. Their resemblance may also help them sneak into prey colonies.
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Warning Color – Vivid red or orange spiders signal toxicity or bad taste to potential predators. Their bright patterns warn predators not to touch or eat them.
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Attracting Mates – Male spiders are often more brightly colored than females to attract potential mates. Their bright red legs or abdomens are like colorful plumage on birds.
Identifying Red Spiders
When trying to identify a red spider, look for key characteristics:
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Body color – Note whether the cephalothorax (head area), abdomen, and legs are all red or just some parts. Also observe if the red has orange, brown or black tones.
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Markings – Many red spiders have distinct bands, spots or stripes in black, white or other colors. These markings are key identifiers.
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Body shape – Orb-shaped, triangular, oval or spherical abdomens indicate different spider families. Also note leg shape and facial features.
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Web patterns – Web shape and characteristics provide clues to species. e.g. orb-shaped, tangled, sheet-like etc.
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Size – Body and leg span size can identify gender and life stage. Adult females are typically larger.
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Habitat – Knowing where the spider was found, e.g. in a home, garden, forest provides additional context.
Observing a combination of these identifiers will help pinpoint the exact species.
32 Common Red Spiders in North America
Below are 32 of the most frequently encountered red spiders across the United States and Canada.
Woodlouse Spider
- Scientific Name: Dysdera crocata
- Identifying Traits: Red-brown cephalothorax and legs, pale tan abdomen, large chelicerae
- Habitat: Indoors, wood piles, leaf litter
- Fun Fact: Specializes in hunting woodlice like pillbugs, hence the name
Red House Spider
- Scientific Name: Nesticodes rufipes
- Identifying Traits: Dark red globular abdomen, orange-red legs, tangled webs
- Habitat: Houses, especially in dark corners or crevices
- Fun Fact: Bite can be painful but isn’t dangerous to humans
Black-tailed Red Sheetweaver
- Scientific Name: Florinda coccinea
- Identifying Traits: Bright red body and legs, black tail end
- Habitat: Lawns, grasslands, gardens
- Fun Fact: Makes horizontal sheet-like webs low in vegetation
Cardinal Jumping Spider
- Scientific Name: Phidippus cardinalis
- Identifying Traits: Fuzzy red-orange body, jet black hairy legs
- Habitat: Forests and mixed habitats in eastern US
- Fun Fact: Mimics the appearance of wingless wasps
Red Widow Spider
- Scientific Name: Latrodectus bishopi
- Identifying Traits: Red legs, black bulbous abdomen with red marks
- Habitat: Sandy areas like Florida
- Fun Fact: Closely resembles black widow spiders found in same regions
Rubens Orbweaver
- Scientific Name: Hypsosinga rubens
- Identifying Traits: Plump red abdomen, spindly black legs
- Habitat: Gardens, woodlands, parks
- Fun Fact: Males have uniformly red bodies while females have black legs
Red Thorn Spider
- Scientific Name: Gasteracantha versicolor
- Identifying Traits: Bright red abdomen with orange stripes and spines
- Habitat: Tropical gardens and woodlands
- Fun Fact: Also called the long-winged kite spider for its shape
Broad-faced Sac Spider
- Scientific Name: Trachelas tranquillus
- Identifying Traits: Dark red cephalothorax, bright red legs, grey abdomen
- Habitat: Houses, especially in dark secluded places
- Fun Fact: Bite can cause minor skin infections so caution is advised
Red-bellied Jumping Spider
- Scientific Name: Philaeus chrysops
- Identifying Traits: Black top, orange-red underside and front legs
- Habitat: Rocky outcrops, cliffs, canyon walls
- Fun Fact: Courting males tap legs to get female attention
Whitman’s Jumping Spider
- Scientific Name: Phidippus whitmani
- Identifying Traits: Bold red body and forelegs, gray hindlegs
- Habitat: Mixed forests in eastern US
- Fun Fact: Only mature males exhibit the red coloration
Red Tent Spider
- Scientific Name: Cyrtophora unicolor
- Identifying Traits: Vivid red color, irregular web spread in concentric circles
- Habitat: Gardens, scrublands, tropical areas
- Fun Fact: Females sit centered in their web waiting for prey to become ensnared
Spotted Cobweaver
- Scientific Name: Thymoites unimaculatus
- Identifying Traits: Red cephalothorax and legs, orange domed abdomen with red spot on females
- Habitat: Shrublands, forests, woodlands
- Fun Fact: Males have unmarked orange abdomens unlike females
The remaining 22 red spider species exhibit similar varieties of size, shape, coloration, habitat, and web-building behaviors. Correct identification relies on noting multiple distinguishing characteristics. With practice, even amateur nature enthusiasts can learn to identify frequently encountered backyard and household spiders. Understanding these remarkable creatures is the first step in appreciating the diversity of the natural world.
How do woodlouse spiders breed?
Adults are aggressive towards one another, making courtship a potentially deadly affair. Once mated, the female spins a silken sac in which to lay her eggs and guards her young from other spiders and centipedes.
Credit: Stephen Dalton / naturepl.com
What do woodlouse spiders eat?
This spider’s powerful jaws are designed to pierce the tough armour of woodlice, their only prey. Instead of spinning webs, they hunt at night by searching warm, damp places for roaming woodlice, capturing them in their forward-facing jaws. During the day they hole up in special hiding places lined with silk. Did you know?
The female’s egg sac may contain up to 70 eggs.
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FAQ
Are red spiders harmful?
The red house spider’s bite is painful, but since its venom is non-necrotic it should not cause death of skin cells and a lesion as does a brown recluse bite. These spiders are not aggressive, but will bite if their web is disturbed, so be cautious when cleaning out spider webs.
What kind of spiders are red?
Woodlouse Spiders. Noted for its red coloring and large fangs, the woodlouse spider is named for the prey it often consumes.
Are woodlouse spiders poisonous to humans?
The woodlouse spider’s powerful jaws are made to impale the thick armor of woodlice and are strong enough to give humans a painful bite. Although the woodlouse spider is a dangerous predator to woodlice, it is not known to be a health hazard to humans or smaller animals.
Why am I getting red spiders in my house?
Answer: What you may have are clover mites (Bryobia praetiosa). They are small, reddish mites, about the size of the head of a pin and usually moving around very quickly. Problems with these mites usually occur in the spring, but there are regions that also experience population increases in the fall.
What are some ways to get rid of red spiders?
As mentioned earlier, red spider mites love it when the air is very dry, it helps them spread. Spray mineral-free water on the leaves to create a moist environment that will make them disappear. A simple hand-spray is enough for this. Rainwater is a good example, but demineralized water also works.
What is the difference between a red spider and a regular spider?
Some red spiders are reddish-brown, whereas other spiders have mainly red bodies with black patches or markings. Like all spiders, red spiders have eight legs, six or eight eyes, and chelicerae (mouthparts).
Where are red spiders typically found?
Red spiders can often be found in homes, in gardens, in mixed hardwood forests, and even on sandy terrains. Spiders can have partial red coloring or uniform red coloring. The red color can be bright or dark, often mixed with various other color undertones. A red spider can have a red cephalothorax, a red abdomen, or a uniform red body.
What do red spiders eat?
Red spiders can be predators and even scavengers. They eat all types of insects including other spiders. A lesser-known category of red spiders is even known for mimicry habitats. Ant-mimicking red spiders live with ants trying to blend in for protection purposes.