12 Scary Redback Spider Facts

This is one of the best-recognizable spiders on the planet, and if you find one, you better make sure to get away from it as fast as possible!

In this post, you’ll discover the ultimate list of redback spider facts, one of the most venomous and scary spiders in the world, and one of the most dangerous animals in Australia!

1. They originate from Australia

The redback spider is a highly venomous spider that originates from southern Australia and the deserts in the west of the country.

You don’t have to look far to figure out how they got their name, because the female redback spiders have a distinctive red marking on the upper side of their back. The lower part of this red area is shaped like an hourglass as well.

redback spider facts
The spider / David McClenaghan, CSIRO / https://creativecommons.org/licenses/by/3.0/deed.en

2. These spiders live all around the world

Apart from having spread all across Australia, these spiders also colonized many other parts of the world.

These countries include Southeast Asia, New Zealand, the United Arab Emirates, Japan, and several countries in Europe, including greenhouses in Belgium!

3. They live in or near the homes of people

So where do redback spiders live, then?

Unfortunately, they live in the exact place you don’t want them to live, near or even inside your house!

They prefer warm and sheltered locations and as these are mostly nocturnal creatures, you won’t see them a lot during the day. The female is the one who spins the web, which happens during the night.

redback spider near the house
Female spider / Charles Haynes / https://creativecommons.org/licenses/by-sa/2.0/deed.en

4. Redback spiders have another name as well

The redback spider is part of the genus Latrodectus, better known as the “widow spiders.” This genus is considered to be cosmopolitan which means its distribution is spread all across the globe.

The scientific name of the redback spider is “Latrodectus hasselti” and it’s also sometimes called the “Australian black widow,” referring to its place of origin and the genus it belongs to.

5. Females redback spiders are much larger than males

One of the most remarkable redback spider facts is that females are much bigger than male redback spiders. Females can grow up to 10 millimeters (0.4 inches) long while males are just 3 to 4 millimeters (0.12 to 0.16 inches) long.

The males also don’t have the distinct hourglass-shaped red mark on their backs.

6. You don’t want to get entangled in this spider’s web

One of the most horrific redback spider facts is the thought of being entangled in one of these creature’s web. The feeding process is one of the most horrendous imaginable!

First, they spray the unfortunate creature that finds itself trapped in the web with some sort of superglue from its spinnerets, which completely immobilizes it by gluing its limbs and other moveable body parts to its body.

When the victim stops struggling, they wrap it with silk to further immobilize it and the spider starts biting it on the head and body, multiple times. Then it’s hauled off to the spider’s secluded feeding area to be devoured completely, bit by bit.

While the animals trapped in its web are usually small insects, these can also include larger animals such as other spiders and even lizards. These are usually left struggling for hours until they can be approached safely to start the feeding process.

redback spider and lizard
An unfortunate lizard / Calistemon / https://creativecommons.org/licenses/by-sa/3.0/deed.en

7. Males have to steal leftovers to get food

The female redback spiders are the ones weaving the web, so how do males get food, one might wonder?

The only option for the males is to wait until the female is finished and hope there’s something left! If not, they have to be a bit sneaky and try to steal some food while the female isn’t paying attention.

It’s no wonder that the female redback spiders are more than double the size of males, right?

8. Female redback spiders engage in sexual cannibalism

One of the weirdest redback spider facts is that it’s one of the few types of spiders that display the act of sexual cannibalism while mating.

And yes, this is exactly what it sounds like, the male redback spiders get devoured alive while they impregnate the female!

But check this, the males get so excited about this fantasy they have that they actually encourage this behavior. They place their own abdomen on top of the female’s mouth on purpose so she would start chewing away on it.

This behavior isn’t just limited to the adult redback spiders, because it’s very common for strong spiderlings to eat their weaker siblings in what is referred to as “sibling cannibalism.”

Pretty gruesome stuff, don’t you think?

redback spiderlings
Redback spiderlings / Bidgee / https://creativecommons.org/licenses/by/3.0

9. Eggs can be fertilized years after the male has been eaten

It’s estimated that 2 out of 3 times, the male gets eaten by the female after releasing his sperm during sexual intercourse. The first question that comes to mind then (among many others) is, doesn’t this hurt the reproductive cycle of these creatures?

After all, this means that not too many males will be around to fertilize the female’s eggs, right?

One of the most fascinating redback spider facts is that the sperm of the male can be stored by the female in an organ called the “spermathecae.” What’s even more remarkable is that this can be used for up to two years to fertilize the female’s eggs!

You see now why having the male around isn’t exactly needed?

10. Redback spiders have several predators

The male redback spider has a lot of issues as it is. The female, on the other hand, doesn’t have a quiet and relaxing life either.

While she engages in some pretty gruesome stuff to kill the prey she caches, she also has to worry about being devoured herself. Several creatures get pretty excited by seeing that hourglass-shaped marking on her back.

These include other spiders such as the black house spider, the cellar spider, and the giant daddy-long-legs spider (what a great name isn’t it?). Redback spiders also have to fear the “redback spider-hunting wasp” which can become its parasite resulting in its death.

female redback spider facts
Female spider / Robertwhyteus / https://creativecommons.org/licenses/by-sa/4.0/deed.en

11. Bites of this spider cause a specific type of illness

While bites of the redback spider aren’t usually lethal, even though the bites may become fatal, they can cause severe pain for the person suffering from one. They are also responsible for the most bites of any spider in Australia.

Bites of the redback spider cause the syndrome of latrodectism in humans, characterized by sweating, vomiting, muscle rigidity, and extreme pain. The extreme pain can persist for up to 24 hours!

12. Antivenom has been available since 1956

Antivenom for bites of the redback spider has been developed and available since 1956 by “Commonwealth Serum Laboratories,” a global company specialized in the matter.

Let’s just hope you don’t come across this scary and horrible creature any time soon!

the scary redback spider
The scary spider / John Tann / https://creativecommons.org/licenses/by/2.0/deed.en