Difference Wiki

Black Widow Spider vs. Redback Spider: What's the Difference?

By Aimie Carlson & Janet White || Published on June 21, 2024
Black Widow Spiders are known for their neurotoxic venom and hourglass marking, while Redback Spiders, a cousin, have similar venom but distinctive red dorsal stripes.

Key Differences

Black Widow Spiders, predominantly found in North America, are famous for their potent venom, which can cause severe pain and muscle spasms in humans. Conversely, the Redback Spider, native to Australia, shares a similar venom potency but is easily identified by its characteristic red stripe on the back, unlike the Black Widow's hourglass.
Both spiders belong to the Latrodectus genus, indicating a close relationship, their habitats differ greatly. Black Widows prefer temperate regions across the United States, whereas Redbacks are more adapted to the Australian climate, thriving in both natural and urban settings.
The female Black Widow is particularly noted for its sexual cannibalism, often consuming the male after mating. This behavior is less commonly observed in Redback Spiders, although it does occur, highlighting a fascinating aspect of their reproductive strategies.
In terms of appearance, aside from the distinctive markings, Black Widows often have a shinier, globular abdomen, whereas Redbacks' abdomens are slightly longer and adorned with additional markings, providing a visual cue to differentiate them.
Despite their dangerous reputation, fatalities from either spider are extremely rare due to the availability of antivenom. However, the fear and fascination surrounding them contribute significantly to their notoriety in their respective regions.

Comparison Chart

Geographic Location

North America

Distinctive Marking

Red hourglass marking on the underside of the abdomen
Red stripe (or multiple stripes) on the dorsal side


Neurotoxic, causing pain and muscle spasms
Similar neurotoxic effects

Habitat Preference

Prefers temperate climates, often found in secluded, dark areas
Adapts well to urban and natural environments

Reproductive Behavior

Known for sexual cannibalism
Sexual cannibalism occurs but is less common

Black Widow Spider and Redback Spider Definitions

Black Widow Spider

Notorious for its potent venom that affects the nervous system.
A bite from a Black Widow Spider requires immediate medical attention.

Redback Spider

Thrives in both natural and urban Australian environments.
Redback Spiders have adapted well to living alongside humans in Australia.

Black Widow Spider

Found across various regions in North America.
Black Widow Spiders are common in both desert and forested areas of North America.

Redback Spider

An Australian spider recognized by its red dorsal stripe and neurotoxic venom.
The Redback Spider is often found lurking in garden sheds and under outdoor furniture.

Black Widow Spider

Rarely lethal to humans due to effective antivenom.
Despite its fearsome reputation, deaths from Black Widow bites are extremely rare.

Redback Spider

Antivenom availability has made fatalities rare.
Fatalities from Redback Spider bites are uncommon, thanks to the availability of antivenom.

Black Widow Spider

Prefers solitary living, with females occasionally exhibiting sexual cannibalism.
After mating, the female Black Widow Spider sometimes eats the male.

Redback Spider

Less likely to engage in sexual cannibalism compared to the Black Widow.
Redback Spiders may not always consume their mates, unlike their North American cousins.

Black Widow Spider

A venomous spider known for its glossy black color and red hourglass marking.
The Black Widow Spider can often be found in dark, undisturbed areas of the garage.

Redback Spider

Shares a similar venom potency to the Black Widow, affecting the nervous system.
Bites from Redback Spiders can cause significant discomfort and require antivenom treatment.


What is the main difference between Black Widow and Redback Spiders?

The main difference is their geographic location and distinctive markings; Black Widows have an hourglass mark, while Redbacks have a red dorsal stripe.

Are Black Widow Spider bites fatal?

Fatalities are extremely rare due to the effectiveness of antivenom.

Where can you find Redback Spiders?

Redback Spiders are commonly found in Australia, in both urban and natural settings.

Do both spiders have the same type of venom?

Yes, both have neurotoxic venom that affects the nervous system, but the symptoms and severity can vary.

What is sexual cannibalism in spiders?

It refers to the behavior where the female consumes the male after mating, observed in both species but more common in Black Widows.

How do you treat a bite from these spiders?

Immediate medical attention and, if necessary, antivenom treatment are recommended for bites from both spider types.

What are the habitats of Black Widow Spiders?

They prefer dark, secluded areas in temperate climates across North America.

Are there any preventative measures against spider bites?

Avoiding dark, cluttered spaces, wearing gloves when reaching into dark areas, and regular cleaning can help prevent bites.

Is it easy to identify these spiders?

Yes, the distinctive markings (hourglass for Black Widows, dorsal stripe for Redbacks) aid in identification.

Can pets be affected by these spider bites?

Yes, pets can be affected, but the severity depends on the size of the pet and the amount of venom injected.

Can Redback Spiders be found outside of Australia?

While native to Australia, Redbacks have been found in other countries, likely due to human transportation.

What is the lifespan of these spiders?

The lifespan can vary, but female Black Widows can live up to three years, while Redbacks may live up to two years.

Do these spiders have any natural predators?

Yes, they have natural predators such as birds, lizards, and other spiders.

How do Black Widow and Redback Spiders catch their prey?

They use their webs to trap insects, which they then immobilize with their venom.

What should you do if you find a spider web in your house?

If you suspect it belongs to a venomous spider, it's best to contact pest control rather than removing it yourself.

Do both species of spiders live in solitude?

Yes, both are generally solitary, except during mating or if females are guarding egg sacs.

How do you differentiate between a male and female in these species?

Females are larger and more distinctly marked than males, who are often smaller and less colorful.

What is the role of antivenom in treating spider bites?

Antivenom neutralizes the venom, significantly reducing symptoms and preventing serious complications.

How do changes in environment affect these spiders?

They are adaptable but prefer stable environments with ample prey and hiding spots; extreme changes can affect their survival.

How often do these spiders mate?

Mating frequency can vary, but generally occurs in the warmer months when food is abundant.
About Author
Written by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.
Co-written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.

Trending Comparisons

Popular Comparisons

New Comparisons