If you’ve found a red spider in your house and are wondering what it is, you may need to take a closer look. Does the spider have a red body and legs or does it just have a red back? Is it tiny, small or quite large? Is it a jumping spider or something altogether more scary? Read about the characteristics and descriptions of the most common red spiders to see which arachnid you’ve found.

Tiny Red Spiders

If you’ve come across some very small red spiders, they are most likely clover mites. Mites are a type of arachnid and the clover mite is smaller than a pinhead. They can be found in large numbers across the US and can infest homes looking for food or shelter. While not dangerous to humans or to the structural integrity of your home, they leave a bright red stain when squashed and may be difficult to control.

Clover Mites

Scientific name: Bryobia praetiosa
Size: Between 0.75 and 0.85 mm (0.030–0.033 in) long
Distinguishing features: Younger mites and eggs are bright red. Adults have a long pair of front legs.
Habitat: Clover mites are usually found in healthy grass lawns and on sun-exposed walls across the world.
Dangerous to humans?: No. They might be annoying and cause staining to fabrics and floors but they are not dangerous.
How to get rid of clover mites: To stop clover mites from infesting your home, trim grass back if it comes up to the door or walls. Use miticide treatments for barrier protection. If the red clover mites are already inside, vacuuming them up is the easiest way to get rid of them, although take care to avoid crushing them as they will leave red stains behind.

Spiders With a Red Body

Although there are a couple of spiders that might fit this description, the most common red- bodied spider is the woodlouse spider. Getting its name from the fact that it predominantly eats woodlice, this bright red to dark red spider can look quite menacing due to the large fangs protruding from its mouthparts. It can be beneficial in the garden as it doesn’t eat plants, only pests. You probably don’t want to see these red spiders inside your home, however, as they can have a nasty bite.

Red house spiders also fall into this category, and while they are found in some parts of the US, they’re not generally found in the western states.

Woodlouse Spider

Scientific name: Dysdera crocata
Size: Adult females can grow to a body length of 11–15 mm (0.43–0.59 in).
Distinguishing features: This red house spider has large, powerful mouthparts or “chelicerae” and does not spin webs to catch food.
Habitat: Leaf litter and human houses, primarily across the northern hemisphere.
Dangerous to humans?: No. The red woodlouse spider is poisonous and can and will bite humans if threatened but the amount of venom it can inject is not large enough to be harmful to humans. Some itching at the bite site may occur but shouldn’t last very long. If you happen to be allergic to spider venom, however, contact a medical professional if you have trouble breathing or a lesion appears at the bite area.
How to get rid of woodlouse spiders: Prevent red spiders coming into your house by sealing up exterior cracks and gaps, especially around windows. Install a tight-fitting door sweep and remove potential nesting sites such as plants and trash cans from around exterior entrances. In the case of a large number of red spiders around your home, contact a local pest control company.

Red House Spider

Scientific name: Nesticodes rufipes
Size: The larger female can have a body length of 5-8 mm (0.2 – 0.3 in).
Distinguishing features: The rounded abdomen of the red house spider can mean it’s sometimes mistaken for a type of black widow.
Habitat: Houses and yards, most commonly in California, Texas and Florida.
Dangerous to humans?: No. Red house spiders can bite humans but their venom is non-toxic meaning that bites should not require any special medical attention.
How to get rid of red house spiders: Frequent dusting of corners, door frames and clearing clutter will discourage red house spiders from taking up residence in your home. Seal up any cracks in the exterior of your house to prevent them from coming inside. If you have any sort of red house spider infestation, contact a professional pest control company.

Spiders With Red Markings

Most commonly, there are two species of spider with red markings on them. One is the Johnson’s jumping spider which has a bright red abdomen. The other is the black widow which has a distinctive red hourglass shape on its abdomen. It’s important to be able to tell the difference between these two red backed spiders as the black widow is notorious for its potentially dangerous bite.

Red-Backed Johnson’s Jumping Spider

Scientific name: Phidippus johnsoni
Size: Males and females grow to approx. 10mm (0.4 inches) in body length
Distinguishing features: This black spider has a bright red back with the male having a solid red abdomen and the female having a black stripe on a red back.
Habitat: Generally found between the Pacific coast and the Rocky Mountains. The red backed jumping spider prefers dry woodlands or coastal dune habitats.
Dangerous to humans?: No. Not to be confused with the actually venomous “redback spider” (Latrodectus hasselti), these red back jumping spiders are not venomous to humans. In the unlikely event of a bite, you will not need medical attention.
How to get rid of red-backed jumping spiders: If you find a lot of jumping spiders inside your home, vacuuming them up is the easiest way to get rid of them. Otherwise, a pest control company can treat your property with preventive barrier sprays.

Black Widow

Scientific name: Latrodectus hesperus – the Western black widow
Size: Females can grow to 14–16 mm (0.5 in) in body length
Distinguishing features: This spider is shiny black with a bulbous abdomen and the famous bright red hourglass shape, although this can sometimes also be white or yellow.
Habitat: This species of black widow is found throughout western North America.
Dangerous to humans?: Yes. The black widow is highly venomous and symptoms from a bite can range from mild irritation to a severe reaction. Female black widow venom acts as a neurotoxin to humans so seek medical advice if you have been bitten by a black widow spider.
How to get rid of black widow spiders: If you see black widow spiders in your home or yard, you can contact a professional pest control company to remove them. To stop them from entering your home, install tight-fitting door sweeps, seal up any holes or cracks in the exterior of your home and remove potential hiding spots by getting rid of clutter in your yard and garage.

Spiders are a common sight anywhere you are, with many locations hosting more than their fair share of large and venomous arachnids. Most people are probably familiar with black widow spiders, wolf spiders and the hobo spider, but what are the bright red spiders that can be found in houses and yards?

Red Spider Facts and Information

Find out about the characteristics and habitats of the different types of red spider. Learn about and identify the clover mite, red house spider, woodlouse spider, jumping Johnson’s spider and the black widow.

Spiders come in all shapes, sizes and colors and with a variety of different traits and behaviors. If you see a red spider and you don’t know what it is, the main question you might have is: is it dangerous? Check out the information on each spider to see whether you should be worried or not and learn more about each arachnid on the way.

Red Spider FAQs

Are red spiders poisonous?

This is a common question about red spiders and most spiders in general. For the vast majority of spiders, even if they have poison or venom, the amount they can inject into a human is very small and usually will not cause any serious health issues. The exceptions are: if you happen to be allergic to spider venom and also, if a black widow bites you. In either case, the reaction can be treated and it’s extremely rare for severe symptoms to occur.

Is a bright red spider dangerous?

In nature, bright colors usually have two purposes:

• To attract other creatures for mating or pollination
• To act as a warning that the creature is toxic. This is sometimes true and sometimes just used as a survival mechanism

So if you see a bright red spider, should you be scared of it? In reality, red spiders do not pose any more of a threat than their counterparts of any other color. While it’s possible that you could be bitten by a red house spider or a woodlouse spider, neither one will cause you serious harm. If you see tiny little bright red clover mites, these are also totally safe for humans, if very annoying.

What kind of red spiders are there?

The most common red spider you’ll see is the woodlouse spider. These can be found in homes and yards across the nation. You may see a red house spider but these are not frequently found in the western states. Clover mites are tiny arachnids that may be mistaken for little spiders and are common almost everywhere. There are also a couple of species of spider with black bodies and bright red markings, such as the Johnson’s jumping spider and the black widow. Certain hobo spiders may also seem reddish in color, and can be identified by their large palpi or mouth parts, which can look like boxing gloves.

Fun Facts About Red Spiders

• The most venomous red spider is the redback spider (Latrodectus hasselti) that is mainly found in Australia.
• Clover mites found in the US are female and do not need males to reproduce. This is called “parthenogenesis” and means that the offspring are full clones of the mother.
• The woodlouse spider is so-called because it mainly eats woodlice. Woodlice also go by different names, which means that this spider is also known by a few different handles such as: sowbug spider, pillbug hunter, slater spider and wood spider.
• Jumping spiders, such as the red backed Johnson’s jumping spider, can leap many times their own body length if they need to get away quickly. The Johnson’s jumping spider does this by changing its blood pressure to increase the amount of blood going to its legs. The sudden expansion of its eight legs causes the spider to fly through the air.
• The web of a black widow can look like a bit of a mess but they are deliberately tangled to trap prey until the spider can paralyze it with its venom. The eggs of the black widow are also stored in the web, attached in a cocoon until they hatch.