The red-backed jumping spider, Phidippus johnsoni, is found throughout the Western United States and Canada. The spider has a black body and the back of its abdomen is bright red.
Description of the Red-Backed Jumping Spider
The redbacked jumping spider is generally quite easy to identify. It’s body is predominantly black with a brightly red colored abdomen. The abdomen of the smaller male is completely and uniformly red while the female’s back is red with a black longitudinal stripe along the abdomen. Sometimes, there are a few small white or yellow dots on the abdomen and the red area itself is surrounded by a thin yellow or white line.
The spider’s chelicerae (jaws) are iridescent and teal-colored. The red-backed jumping spiders shares this beautiful trait with many other species of jumping spiders.
With its black and red appearance, the red-backed jumping spider mimics the appearance of velvet wasps (mutillid wasps). The exact evolutionary reason behind this mimicry is still unknown. However, it is believed that the appearance should deter potential predators as velvet wasps can deal a painful sting.
Within its range in the Western United States, Phidippus johnsoni can be confused with Phidippus carneus. However, Ph. carneus usually has distinctive white bands around the legs and the white ring around the red coloration on the back is usually thicker in Ph. carneus. Another similar-looking species is Phidippus clarus, which occurs mostly in the Eastern United States.
The red-backed jumping spider is relatively large, compared to other jumping spiders. Females reach an average body length of 0.35-0.55 in. (9-14 mm). Their legs are quite short and their total leg span is just slightly longer than the body size. Male individuals are smaller and reach and average body size of 0.25-0.45 in. (6-11 mm).
Jumping spiders do not spin webs in order to catch prey animals. They are active hunters preying on flies, moths, bugs as well as other spiders. Jumping spiders mainly use their ability to spin silk to spin a “safety line” during their jumps. If the jump fails, the spiders falls into the safety line from where it can climb back to safety.
The red-backed jumping spider is not an aggressive spider and its first instinct is to run away (or jump away) if humans or animals approach it. In rare occasions, they do bite humans or pets leading to some local swellings or potentially a mild headache. Other known symptoms are not known from the relatively mild venom of jumping spiders.
Scientific Classification of Phidippus johnsoni
- Kingdom: Animalia
- Phylum: Arthropoda
- Subphylum: Chelicerata
- Class: Arachnida
- Order: Araneae
- Infraorder: Araneomorphae
- Family: Salticidae
- Genus: Phidippus
- Species: Phidippus johnsoni
Distribution of the Red-Backed Jumping Spider in the USA
The red-backed jumping spider occurs in the Western United States, west of the Great Plains. The spider is especially common in California and is also found in the following U.S. States: New Mexico, Colorado, Wyoming, Montana, Arizona, Utah, Idaho, Nevada, Oregon, Washington.
- Taxon details: World Spider Catalogue
- Binomial name from: Peckham & Peckham, 1883
- Phidippus johnsoni Fact Sheet
16 thoughts on “Phidippus Johnsoni – Red-Backed Jumping Spider”
Friend of mine found this spider in her back yard near the rabbit hutch. her location is a couple miles north of the Washington State border in British Columbia Canada. Here are some pictures for identification purposes I cannot seem to be able to post an image
Hello Dowdall, thanks for getting in touch and for uploading these great pictures. This is a female red-backed jumping spider (Phidippus johnsoni). Despite their name, they often come with a yellow-colored abdomen.
Here is more information about them: https://usaspiders.com/phidippus-johnsoni-red-backed-jumping-spider/
another image of the spider
Found a Phidippus Johnsoni, male, in my garage in Fairview Heights, Southern Illinois. I am so afraid of spiders that I kill him without having second thoughts. Sorry. Then I put it in a zip lock bag to be sure I had seen well for at 8:30am when the sun rays hit it was a red, with deep black ” big dented head”, black legs, and measuring close to 1/2 inch.
It looks exactly as the picture portrayed in : USA Spiders , Phidippus Johnsoni-Red-Backed Jumping Spider .
PD: I was unable to upload an image
Silly me… I thought it was a relative to the Black Widow.
I just caught one similar to this one. (I am in the mts. of S W Oregon.) Difference is there is no color on the bottom. Legs have hair but very hard to see them. The 2 color strips on the back are a reddish brown. More brown than red. Is this a ‘mutation’ of the red jumper? We have those too. I understand they are not poisonous but I am very allergic to them & this booger is big! Never seen 1 so big!
I’m in southern Ontario’s Niagara area and took this shot the other day in my living room. It sure looks like a redback, but what’s it doing so far from ours natural range?
I found this crawling on my tea tumbler in the car and was able to release him in the parking lot.
Hello Linda, this is a male Phidippus sp. jumping spider. Your location would help to narrow it down to a specific species. If you are located in California or elsewhere in the western United States, it’s most likely a red-backed jumping spider (Phidippus johnsoni): https://usaspiders.com/phidippus-johnsoni-red-backed-jumping-spider/
Found this in our house. Is this dangerous?
Hi Baam, no, this spider is definitely not dangerous. This is a harmless red-backed jumping spider (Phidippus johnsoni): https://usaspiders.com/phidippus-johnsoni-red-backed-jumping-spider/
Hi there are some of these on my balcony but I am in Italy should I b worried for my pets??
Hi Seff, no need to be worried. This is a male Philaeus chrysops jumping spider. It’s not dangerous for humans or pets.
hey every one , im amir from iran
and i find my little jumping spider that is on the top of the site 😍 thats so nice
i wanna take a picture for you
Hi Amir, thanks for sharing! This is most likely a male Philaeus chrysops jumping spider.
Io abito in Italia centrale e qualche ora fa ho fatto questa foto del ragno nel mio giardino..sembra proprio lo stesso ragno .magari qualcuno potrà dirmi come sia possibile ?
This little male kept crawling up the wall and freaking my wife out. Every time I tried to catch it, it would drop, so I finally figured out it’s movements and safely got the little dude outside, where I assume it belongs.